| 1. |
- Johansson, Birgitta, et al.
(author)
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Atrial function after left atrial epicardial cryoablation for atrial fibrillation in patients undergoing mitral valve surgery
- 2012
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In: Journal of Interventional Cardiac Electrophysiology. - : Springer Science+Business Media B.V.. - 1383-875X .- 1572-8595. ; 33:1, s. 85-91
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Journal article (peer-reviewed)abstract
- PURPOSE: To explore the effects on atrial and ventricular function of restoring sinus rhythm (SR) after epicardial cryoablation and closure of the left atrial appendage (LAA) in patients with mitral valve disease and atrial fibrillation (AF) undergoing surgery.METHODS: Sixty-five patients with permanent AF were randomized to mitral valve surgery combined with left atrial epicardial cryoablation and LAA closure (ABL group, n = 30) or to mitral valve surgery alone (control group, n = 35). Two-dimensional and Doppler echocardiography were performed before and 6 months after surgery.RESULTS: At 6 months, 73% of the patients in the ABL group and 46% of the controls were in SR. Patients in SR at 6 months had a reduction in their left ventricular diastolic diameter while the left ventricular ejection fraction was unchanged. In patients remaining in AF, the left ventricular ejection fraction was lower than at baseline. The left atrial diastolic volume was reduced after surgery, more in patients with SR than AF. In patients in SR, the peak velocity during the atrial contraction and the reservoir function were lower in the ABL group than in the control group.CONCLUSIONS: In patients in SR, signs of atrial dysfunction were observed in the ABL but not the control group. Atrial dysfunction may have existed before surgery, but the difference between the groups implies that the cryoablation procedure and/or closure of the LAA might have contributed.
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| 2. |
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| 3. |
- Agnvall, Beatrix, et al.
(author)
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Heritability and Genetic Correlations of Fear-Related Behaviour in Red Jungelfowl -Possible Implications for Early Domestication
- 2012
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:4, s. e35162-
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Journal article (peer-reviewed)abstract
- Domesticated species differ from their wild ancestors in a number of traits, generally referred to as the domesticated phenotype. Reduced fear of humans is assumed to have been an early prerequisite for the successful domestication of virtually all species. We hypothesized that fear of humans is linked to other domestication related traits. For three generations, we selected Red Junglefowl (ancestors of domestic chickens) solely on the reaction in a standardized Fear of Human-test. In this, the birds were exposed for a gradually approaching human, and their behaviour was continuously scored. This generated three groups of animals, high (H), low (L) and intermediate (I) fearful birds. The birds in each generation were additionally tested in a battery of behaviour tests, measuring aspects of fearfulness, exploration, and sociality. The results demonstrate that the variation in fear response of Red Junglefowl towards humans has a significant genetic component and is genetically correlated to behavioural responses in other contexts, of which some are associated with fearfulness and others with exploration. Hence, selection of Red Junglefowl on low fear for humans can be expected to lead to a correlated change of other behavioural traits over generations. It is therefore likely that domestication may have caused an initial suite of behavioural modifications, even without selection on anything besides tameness.
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| 4. |
- Agnvall, Beatrix, 1980-, et al.
(author)
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Red Junglefowl (Gallus gallus) selected for low fear of humans are larger, more dominant and produce larger offspring
- 2014
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In: animal. - : Cambridge University Press. - 1751-7311. ; 8:9, s. 1498-1505
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Journal article (peer-reviewed)abstract
- Many traits associated with domestication are suggested to have developed as correlated responses to reduced fear of humans. Tameness may have reduced the stress of living in human proximity and improved welfare in captivity. We selected Red Junglefowl (ancestors of all domestic chickens) for four generations on high or low fear towards humans, mimicking an important aspect of the earliest period of domestication, and tested birds from the third and fourth generation in three different social tests. Growth and plumage condition, as well as size of eggs and offspring were also recorded, as indicators of some aspects of welfare. Birds selected for low fear had higher weight, laid larger eggs and generated larger offspring, and had a better plumage condition. In a social dominance test they also performed more aggressive behaviour and received less of the same, regardless of whether the restricted resource was feed or not. Hence, dominance appeared to increase as a consequence of reduced fear of humans. Furthermore, egg size and the weight of the offspring were larger in the less fearful birds, and plumage condition better, which could be interpreted as the less fearful animals being better adapted to the environment in which they were selected.
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| 5. |
- Albert, Frank W., et al.
(author)
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A Comparison of Brain Gene Expression Levels in Domesticated and Wild Animals
- 2012
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In: PLOS Genetics. - : Public Library of Science. - 1553-7390 .- 1553-7404. ; 8:9, s. e1002962-
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Journal article (peer-reviewed)abstract
- Domestication has led to similar changes in morphology and behavior in several animal species, raising the questionwhether similarities between different domestication events also exist at the molecular level. We used mRNA sequencing toanalyze genome-wide gene expression patterns in brain frontal cortex in three pairs of domesticated and wild species (dogsand wolves, pigs and wild boars, and domesticated and wild rabbits). We compared the expression differences with thosebetween domesticated guinea pigs and a distant wild relative (Cavia aperea) as well as between two lines of rats selectedfor tameness or aggression towards humans. There were few gene expression differences between domesticated and wilddogs, pigs, and rabbits (30–75 genes (less than 1%) of expressed genes were differentially expressed), while guinea pigs andC. aperea differed more strongly. Almost no overlap was found between the genes with differential expression in thedifferent domestication events. In addition, joint analyses of all domesticated and wild samples provided only suggestiveevidence for the existence of a small group of genes that changed their expression in a similar fashion in differentdomesticated species. The most extreme of these shared expression changes include up-regulation in domesticates of SOX6and PROM1, two modulators of brain development. There was almost no overlap between gene expression in domesticatedanimals and the tame and aggressive rats. However, two of the genes with the strongest expression differences betweenthe rats (DLL3 and DHDH) were located in a genomic region associated with tameness and aggression, suggesting a role ininfluencing tameness. In summary, the majority of brain gene expression changes in domesticated animals are specific tothe given domestication event, suggesting that the causative variants of behavioral domestication traits may likewise bedifferent.
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| 6. |
- Beltéky, Johan, 1987-, et al.
(author)
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Gene expression of behaviorally relevant genes in the cerebral hemisphere changes after selection for tameness in Red Junglefowl.
- 2017
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In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 12:5
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Journal article (peer-reviewed)abstract
- The process of domestication in animals has led to alterations in behavior, physiology and phenotypic traits, changes that may be driven by correlations with reduced fear of humans. We used Red Junglefowl, ancestors of all domesticated chickens selected for either high or low fear of humans for five generations to study the effects of selection on gene transcription in the cerebral hemisphere, which is heavily involved in behaviour control. A total of 24 individuals from the parental generation as well as from the fifth selected generation were used. Twenty-two genes were significantly differentially expressed at p < 0.05 after false discovery rate (FDR) correction. Those genes that were upregulated in the low fearful animals were found to be involved in neural functions. Gene ontology and pathway analysis revealed enrichment for terms associated with behavioural processes. We conclude that five generations of divergent selection for high or low tameness has significantly changed gene expression patterns in the cerebral hemisphere in the Red Junglefowl population used here, which could underlie a range of changes in the domestic phenotype.
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| 7. |
- Brunberg, Emma, et al.
(author)
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Brain gene expression differences are associated with abnormal tail biting behavior in pigs
- 2013
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In: Genes, Brain and Behavior. - : Wiley. - 1601-1848 .- 1601-183X. ; 12:2, s. 275-281
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Journal article (peer-reviewed)abstract
- Knowledge about gene expression in animals involved in abnormal behaviors can contribute to the understanding of underlying biological mechanisms. This study aimed to explore the motivational background to tail biting, an abnormal injurious behavior and severe welfare problem in pig production. Affymetrix microarrays were used to investigate gene expression differences in the hypothalamus and prefrontal cortex of pigs performing tail biting, pigs receiving bites to the tail and neutral pigs who were not involved in the behavior. In the hypothalamus, 32 transcripts were differentially expressed (P<0.05) when tail biters were compared with neutral pigs, 130 when comparing receiver pigs with neutrals, and two when tail biters were compared with receivers. In the prefrontal cortex, seven transcripts were differently expressed in tail biters when compared with neutrals, seven in receivers vs. neutrals and none in the tail biters vs. receivers. In total, 19 genes showed a different expression pattern in neutral pigs when compared with both performers and receivers. This implies that the functions of these may provide knowledge about why the neutral pigs are not involved in tail biting behavior as performers or receivers. Among these 19 transcripts were genes associated with production traits in pigs (PDK4), sociality in humans and mice (GTF2I) and novelty seeking in humans (EGF). These are in line with hypotheses linking tail biting with reduced back fat thickness and explorative behavior.
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| 8. |
- Buller, Henry, et al.
(author)
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Towards Farm Animal Welfare and Sustainability
- 2018
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In: Animals. - : MDPI. - 2076-2615. ; 8:6
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Research review (peer-reviewed)abstract
- As farm animal welfare becomes an increasingly important component of contemporary global livestock production, animal welfare science and animal welfare policy-making need to find new ways of entering global debates over food security and sustainability. In this paper, we explore the means by which both animal welfare science and policy should articulate with these emerging global debates. Having first established the important gains in animal welfare policy and the maturity of animal welfare science, we identify and explore the potential impact of these current debates and argue that they have the potential for profound change in our understanding of, and our response to, the welfare of animals. We conclude the paper with a number of possible recommendations for how a scientifically informed, sustainable animal welfare policy might flourish.
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| 9. |
- Eklund, Beatrix, et al.
(author)
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Domestication effects on behavioural synchronization and individual distances in chickens ( Gallus gallus)
- 2011
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In: Behavioural Processes. - : Elsevier. - 0376-6357 .- 1872-8308. ; 86:2, s. 250-256
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Journal article (peer-reviewed)abstract
- Behavioural synchrony (allelomimetic behaviour), and inter-individual distances are aspects of social and anti-predator strategies which may have been affected by domestication. Chickens are known to adjust synchronization and inter-individual distances depending on behaviour. We hypothesized that White Leghorn (WL) chickens would show less synchronized behaviour than the ancestor, the red jungle fowl (RJF). Sixty birds, 15 female and 15 male WL and the same number of RJF (28 weeks old) were studied in groups of three in furnished pens (1 m × 2 m) for 24 consecutive hours per group, following 24 h of habituation. Video tapes covering 4 h per group (dawn, 9–10 am, 1–2 pm and dusk) were analysed. Red junglefowl perched significantly more, but there were no breed effects on the frequency or daily rhythm of any other activities, or on average inter-individual distances. Red junglefowl were more synchronized during perching and a tendency for the same was found for social behaviour. After performance of the two most synchronized behaviours, perching and comfort behaviour, individual distance increased more for RJF than WL. According to this study domestication of chickens appears not to have significantly altered the relative frequencies of different activities or average inter-individual distances, but have caused some changes in behavioural synchronization and maintenance of activity-specific inter-individual distances in chickens. The changes may indicate an adaptive response to captivity and domestication.
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| 10. |
- Elfwing, Magnus, et al.
(author)
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The Strong Selective Sweep Candidate Gene ADRA2C Does Not Explain Domestication Related Changes In The Stress Response Of Chickens
- 2014
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In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 9:8, s. e103218-
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Journal article (peer-reviewed)abstract
- Analysis of selective sweeps to pinpoint causative genomic regions involved in chicken domestication has revealed a strongselective sweep on chromosome 4 in layer chickens. The autoregulatory a-adrenergic receptor 2C (ADRA2C) gene is theclosest to the selective sweep and was proposed as an important gene in the domestication of layer chickens. The ADRA2Cpromoter region was also hypermethylated in comparison to the non-selected ancestor of all domesticated chicken breeds,the Red Junglefowl, further supporting its relevance. In mice the receptor is involved in the fight-or-flight response as itmodulates epinephrine release from the adrenals. To investigate the involvement of ADRA2C in chicken domestication, wemeasured gene expression in the adrenals and radiolabeled receptor ligand in three brain regions comparing the domesticWhite Leghorn strain with the wild ancestor Red Junglefowl. In adrenals ADRA2C was twofold greater expressed than therelated receptor gene ADRA2A, indicating that ADRA2C is the predominant modulator of epinephrine release but no straindifferences were measured. In hypothalamus and amygdala, regions associated with the stress response, and in striatum,receptor binding pIC50 values ranged between 8.1–8.4, and the level was not influenced by the genotyped allele. Becausechicken strains differ in morphology, physiology and behavior, differences attributed to a single gene may be lost in thenoise caused by the heterogeneous genetic background. Therefore an F10 advanced intercross strain between WhiteLeghorn and Red Junglefowl was used to investigate effects of ADRA2C alleles on fear related behaviors and fecundity. Wedid not find compelling genotype effects in open field, tonic immobility, aerial predator, associative learning or fecundity.Therefore we conclude that ADRA2C is probably not involved in the domestication of the stress response in chicken, and thestrong selective sweep is probably caused by selection of some unknown genetic element in the vicinity of the gene.
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| 11. |
- Ericsson, Maria, et al.
(author)
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Domestication effects on behavioural and hormonal responses to acute stress in chickens
- 2014
-
In: Physiology and Behavior. - : Elsevier BV. - 0031-9384 .- 1873-507X. ; 133, s. 161-169
-
Journal article (peer-reviewed)abstract
- Comparative studies have shown that alterations in physiology, morphology and behaviour have arisen due to the domestication. A driving factor behind many of the changes could be a shift in stress responses, with modified endocrine and behavioural profiles. In the present study we compared two breeds of chicken (Gallus gallus), the domestic White Leghorn (WL) egg laying breed and its ancestor, the Red Junglefowl (RJF). Birds were exposed to an acute stress event, invoked by 3 or 10 min of physical restraint. They were then continuously monitored for the effects on a wide range of behaviours during a 60 min recovery phase. Blood samples were collected from the chicken at baseline, and after 10 and 60 min following a similar restraint stress, and the samples were analyzed for nine endogenous steroids of the HPA and HPG axes. Concentration of the steroids was determined using validated liquid chromatography tandem mass spectrometry methods. In RJF, an immediate behavioural response was observed after release from restraint in several behaviours, with a relatively fast return to baseline within 1 h. In WL, some behaviours were affected for a longer period of time, and others not at all. Concentrations of corticosterone increased more in RJF, but returned faster to baseline compared to WL. A range of baseline levels for HPG-related steroids differed between the breeds, and they were generally more affected by the stress in WL than in RJF. In conclusion, RJF reacted stronger both behaviourally and physiologically to the restraint stress, but also recovered faster. This would appear to be adaptive under natural conditions, whereas the stress recovery of domesticated birds has been altered by domestication and breeding for increased reproductive output.
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| 12. |
- Eriksson, Jonas, et al.
(author)
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Identification of the yellow skin gene reveals a hybrid origin of the domestic chicken
- 2008
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In: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 4:2, s. e1000010-
-
Journal article (peer-reviewed)abstract
- Yellow skin is an abundant phenotype among domestic chickens and is caused by a recessive allele (W*Y) that allows deposition of yellow carotenoids in the skin. Here we show that yellow skin is caused by one or more cis-acting and tissue-specific regulatory mutation(s) that inhibit expression of BCDO2 (beta-carotene dioxygenase 2) in skin. Our data imply that carotenoids are taken up from the circulation in both genotypes but are degraded by BCDO2 in skin from animals carrying the white skin allele (W*W). Surprisingly, our results demonstrate that yellow skin does not originate from the red junglefowl (Gallus gallus), the presumed sole wild ancestor of the domestic chicken, but most likely from the closely related grey junglefowl (Gallus sonneratii). This is the first conclusive evidence for a hybrid origin of the domestic chicken, and it has important implications for our views of the domestication process.
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| 13. |
- Erlinge, D., et al.
(author)
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Bivalirudin versus Heparin Monotherapy in Myocardial Infarction
- 2017
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In: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 377:12, s. 1132-1142
-
Journal article (peer-reviewed)abstract
- Background The comparative efficacy of various anticoagulation strategies has not been clearly established in patients with acute myocardial infarction who are undergoing percutaneous coronary intervention (PCI) according to current practice, which includes the use of radial-artery access for PCI and administration of potent P2Y12 inhibitors without the planned use of glycoprotein IIb/IIIa inhibitors. Methods In this multicenter, randomized, registry-based, open-label clinical trial, we enrolled patients with either ST-segment elevation myocardial infarction (STEMI) or non-STEMI (NSTEMI) who were undergoing PCI and receiving treatment with a potent P2Y12 inhibitor (ticagrelor, prasugrel, or cangrelor) without the planned use of glycoprotein IIb/IIIa inhibitors. The patients were randomly assigned to receive bivalirudin or heparin during PCI, which was performed predominantly with the use of radial-artery access. The primary end point was a composite of death from any cause, myocardial infarction, or major bleeding during 180 days of follow-up. Results A total of 6006 patients (3005 with STEMI and 3001 with NSTEMI) were enrolled in the trial. At 180 days, a primary end-point event had occurred in 12.3% of the patients (369 of 3004) in the bivalirudin group and in 12.8% (383 of 3002) in the heparin group (hazard ratio, 0.96; 95% confidence interval [CI], 0.83 to 1.10; P=0.54). The results were consistent between patients with STEMI and those with NSTEMI and across other major subgroups. Myocardial infarction occurred in 2.0% of the patients in the bivalirudin group and in 2.4% in the heparin group (hazard ratio, 0.84; 95% CI, 0.60 to 1.19; P=0.33), major bleeding in 8.6% and 8.6%, respectively (hazard ratio, 1.00; 95% CI, 0.84 to 1.19; P=0.98), definite stent thrombosis in 0.4% and 0.7%, respectively (hazard ratio, 0.54; 95% CI, 0.27 to 1.10; P=0.09), and death in 2.9% and 2.8%, respectively (hazard ratio, 1.05; 95% CI, 0.78 to 1.41; P=0.76). Conclusions Among patients undergoing PCI for myocardial infarction, the rate of the composite of death from any cause, myocardial infarction, or major bleeding was not lower among those who received bivalirudin than among those who received heparin monotherapy. (Funded by the Swedish Heart-Lung Foundation and others; VALIDATE-SWEDEHEART ClinicalTrialsRegister.eu number, 2012-005260-10 ; ClinicalTrials.gov number, NCT02311231 .).
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| 14. |
- Fallahshahroudi, Amir, et al.
(author)
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Domestication Effects on Stress Induced Steroid Secretion and Adrenal Gene Expression in Chickens
- 2015
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
-
Journal article (peer-reviewed)abstract
- Understanding the genetic basis of phenotypic diversity is a challenge in contemporary biology. Domestication provides a model for unravelling aspects of the genetic basis of stress sensitivity. The ancestral Red Junglefowl (RJF) exhibits greater fear-related behaviour and a more pronounced HPA-axis reactivity than its domesticated counterpart, the White Leghorn (WL). By comparing hormones (plasmatic) and adrenal global gene transcription profiles between WL and RJF in response to an acute stress event, we investigated the molecular basis for the altered physiological stress responsiveness in domesticated chickens. Basal levels of pregnenolone and dehydroepiandrosterone as well as corticosterone response were lower in WL. Microarray analysis of gene expression in adrenal glands showed a significant breed effect in a large number of transcripts with over-representation of genes in the channel activity pathway. The expression of the best-known steroidogenesis genes were similar across the breeds used. Transcription levels of acute stress response genes such as StAR, CH25 and POMC were upregulated in response to acute stress. Dampened HPA reactivity in domesticated chickens was associated with changes in the expression of several genes that presents potentially minor regulatory effects rather than by means of change in expression of critical steroidogenic genes in the adrenal.
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| 15. |
- Fallahshahroudi, Amir, 1981-
(author)
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Domestication Effects on the Stress Response in Chickens : Genetics, Physiology, and Behaviour
- 2017
-
Doctoral thesis (other academic/artistic)abstract
- Animal domestication, the process where animals become adapted to living in proximity to humans, is associated with the alteration of multiple traits, including decreased fearfulness and stress response. With an estimated population of 50 billion, the domesticated chicken is the most populous avian species in the world. Hundreds of chicken breeds have been developed for meat and egg production, hobby or research purposes. Multidirectional selection and the relaxation of natural selection in captivity have created immense phenotypic diversity amongst domesticates in a relatively short evolutionary time. The extensive phenotypic diversity, existence of the wild ancestor, and feasibility of intercrossing various breeds makes the chicken a suitable model animal for deciphering genetic determinants of complex traits such as stress response. We used chicken domestication as a model to gain insights about the mechanisms that regulate stress response in an avian species. We studied behavioural and physiological stress response in the ancestral Red Junglefowl and one of its domesticated progenies, White Leghorn. An advanced intercross between the aforementioned breeds was later used to map genetic loci underlying modification of stress response. The general pattern of the stress response in chickens was comparable with that reported in mammals, however we identified distinctive differences in the stress modulatory pathways in chickens. We showed that changes in the expression levels of several stress modulatory genes in the brain, the pituitary and the adrenal glands underlie the observed modified stress response in domesticated chickens. Using quantitative trait loci (QTL) mapping, several QTL underlying stress induced corticosterone, aldosterone and baseline dehydroepiandrosterone (DHEA) levels were detected. As a next step, we combined QTL mapping with gene expression (eQTL) mapping and narrowed two QTL down to the putative causal genes, SERPINA10 and PDE1C. Both of these genes were differentially expressed in the adrenal glands of White Leghorn and the Red Junglefowl, had overlapping eQTL with hormonal QTL, and their expression levels in the adrenal glands were correlated with plasma levels of corticosterone and al-dosterone. These two genes thus serve as strong candidates for further functional investigation concerning modification of the stress response during domestication. This dissertation increase the knowledge about genetics and physiology of the stress response in an avian species and its modification during domestication. Our findings expand the basic knowledge about the stress response in chicken, which can potentially be used to improve welfare through appropriate genetic selection.
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| 16. |
- Fallahsharoudi, Amir, 1981-, et al.
(author)
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Changes in pituitary gene expression may underlie multiple domesticated traits in chickens.
- 2019
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In: Heredity. - London : Nature Publishing Group. - 0018-067X .- 1365-2540. ; 122:2, s. 195-204
-
Journal article (peer-reviewed)abstract
- Domesticated animals share a unique set of morphological and behavioral traits, jointly referred to as the domesticated phenotype. Striking similarities amongst a range of unrelated domesticated species suggest that similar regulatory mechanisms may underlie the domesticated phenotype. These include color pattern, growth, reproduction, development and stress response. Although previous studies have focused on the brain to find mechanisms underlying domestication, the potential role of the pituitary gland as a target of domestication is highly overlooked. Here, we study gene expression in the pituitary gland of the domesticated White Leghorn chicken and its wild ancestor, the Red Junglefowl. By overlapping differentially expressed genes with a previously published list of functionally important genes in the pituitary gland, we narrowed down to 34 genes. Amongst them, expression levels of genes with inhibitory function on pigmentation (ASIP), main stimulators of metabolism and sexual maturity (TSHB and DIO2), and a potential inhibitor of broodiness (PRLR), were higher in the domesticated breed. Additionally, expression of 2 key inhibitors of the stress response (NR3C1, CRHR2) was higher in the domesticated breed. We suggest that changes in the transcription of important modulatory genes in the pituitary gland can account not only for domestication of the stress response in domestic chickens, but also for changes in pigmentation, development, and reproduction. Given the pivotal role of the pituitary gland in the regulation of multiple shared domesticated traits, we suggest that similar changes in pituitary transcriptome may contribute to the domesticated phenotype in other species as well.
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| 17. |
- Favati, Anna, et al.
(author)
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The ontogeny of personality traits in the redjunglefowl, Gallus gallus
- 2016
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In: Behavioral Ecology. - : Oxford University Press. - 1045-2249 .- 1465-7279. ; 27:2, s. 484-493
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Journal article (peer-reviewed)abstract
- Consistent behavioral differences among individuals, that is, personality, are described in numerous species. Nevertheless, thedevelopment of behavioral consistency over ontogeny remains unclear, including whether the personality of individuals is consistentthroughout life, and if adult personality can be predicted already at young age. We investigated the ontogeny of personality in thered junglefowl (Gallus gallus) by scoring personality of hatchlings at 5 time points through adulthood, including before and after themajor developmental stages of becoming independent and sexual mature. We use the conceptual framework laid out by Stamps andGroothuis (2010a) to holistically investigate the observed changes in behavioral response over ontogeny. We demonstrate that meanvalues of behavioral responses changed across ontogeny and stabilized after independence. Rank-order consistencies of behavioralresponses were overall low across independence and sexual maturation. Only in 1 case could low rank-order consistencies potentiallybe explained by different phenotypes displaying different amounts of change in behavior; more explorative individuals decreased inexploration after independence, while less explorative individuals remained so. Correlations among behavior varied across ontogenyand weakened after sexual maturation. Our results demonstrate that both absolute values and consistency of behavioral traits maychange across ontogeny and that individual developmental trajectories and adult personality only to some extent can be predictedearly in life. These results have implications for future studies on personality, highlighting that the life stage at which individuals arescored affects the observed consistency of behavioral responses.
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| 18. |
- Fogelholm, Jesper, 1986-, et al.
(author)
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CREBBP and WDR 24 Identified as Candidate Genes for Quantitative Variation in Red-Brown Plumage Colouration in the Chicken
- 2020
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In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 10:1
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Journal article (peer-reviewed)abstract
- Plumage colouration in birds is important for a plethora of reasons, ranging from camouflage, sexual signalling, and species recognition. The genes underlying colour variation have been vital in understanding how genes can affect a phenotype. Multiple genes have been identified that affect plumage variation, but research has principally focused on major-effect genes (such as those causing albinism, barring, and the like), rather than the smaller effect modifier loci that more subtly influence colour. By utilising a domestic × wild advanced intercross with a combination of classical QTL mapping of red colouration as a quantitative trait and a targeted genetical genomics approach, we have identified five separate candidate genes (CREBBP, WDR24, ARL8A, PHLDA3, LAD1) that putatively influence quantitative variation in red-brown colouration in chickens. By treating colour as a quantitative rather than qualitative trait, we have identified both QTL and genes of small effect. Such small effect loci are potentially far more prevalent in wild populations, and can therefore potentially be highly relevant to colour evolution.
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| 19. |
- Foyer, Pemilla, et al.
(author)
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Early experiences modulate stress coping in a population of German shepherd dogs
- 2013
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In: Applied Animal Behaviour Science. - : Elsevier BV. - 0168-1591 .- 1872-9045. ; 146:1-4, s. 79-87
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Journal article (peer-reviewed)abstract
- Early experiences may alter later behavioural expressions in animals and these differences can be consistent through adulthood. In dogs, this may have a profound impact on welfare and working ability and, it is therefore interesting to evaluate how experiences during the first weeks of life contribute to shaping the long-term behaviour. We analysed data from 503 dogs from 105 litters, bred at the Swedish Armed Forces Dog Kennel. For each dog, the data comprised information on dam and sire, sex, litter size, sex ratio of litter, date of birth, and weight at birth, and at 10 days of age. Between the ages of 377 and 593 days, the dogs were tested in a temperament test, assessing their suitability as working dogs. The behaviour test comprised 12 different sub-tests, and was scored on a behavioural rating scale. A principal component analysis showed that the test performance could largely be attributed to four principal components (explaining 55.7% of variation), labelled Confidence, Physical Engagement, Social Engagement and Aggression. We analysed the effects of the different early life variables and sex on the principal component scores (PC scores) using linear modelling. PC scores on Confidence were affected by parity, sex and litter size, and Physical Engagement was affected by parity, growth rate, litter size and season of birth. Social Engagement was affected by growth rate and sex, and Aggression was affected by sex. Some of these effects disappeared when they were combined into a single linear model, but most of them remained significant also when controlling for collinearity. The results suggest that the early environment of dogs have long-lasting effects on their behaviour and coping styles in a stressful test situation and this knowledge can be used in the work with breeding of future military or police working dogs.
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| 20. |
- Foyer, Pernilla, 1971-, et al.
(author)
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Levels of maternal care in dogs affect adult off spring temperament
- 2016
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Journal article (peer-reviewed)abstract
- Dog puppies are born in a state of large neural immaturity; therefore, the nervous system is sensitive to environmental influences early in life. In primates and rodents, early experiences, such as maternal care, have been shown to have profound and lasting effects on the later behaviour and physiology of offspring. We hypothesised that this would also be the case for dogs with important implications for the breeding of working dogs. In the present study, variation in the mother-offspring interactions of German Shepherd dogs within the Swedish breeding program for military working dogs was studied by video recording 22 mothers with their litters during the first three weeks postpartum. The aim was to classify mothers with respect to their level of maternal care and to investigate the effect of this care on pup behaviour in a standardised temperament test carried out at approximately 18 months of age. The results show that females differed consistently in their level of maternal care, which significantly affected the adult behaviour of the offspring, mainly with respect to behaviours classified as Physical and Social Engagement, as well as Aggression. Taking maternal quality into account in breeding programs may therefore improve the process of selecting working dogs.
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| 21. |
- Gabrielle, Lunden, et al.
(author)
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Play ontogeny in young chickens is affected by domestication and early stress
- 2022
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In: Scientific Reports. - : NATURE PORTFOLIO. - 2045-2322. ; 12:1
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Journal article (peer-reviewed)abstract
- Play is common in young homeotherm animals and has an important role as a tentative indicator of positive states of welfare. Furthermore, during domestication play is believed to have increased in frequency in several species as part of the domestication syndrome. Here, we studied the ontogeny of play in chickens in two experiments. The first compared the behavioural development between domesticated White Leghorn (WL) laying hen chicks and ancestral Red Junglefowl (RJF) and the second compared the same between WL chicks that had experienced the stress of commercial hatchery routines and a control group, hatched under calm conditions. In both experiments, 10 groups of four chicks each from each of the groups were moved twice per week to an enriched and fully enclosed play arena, starting at day 8 and finishing day 39 or 53 after hatch. In the arena, the frequency of play behaviours was recorded during 30 min and divided into object, locomotory and social play. In experiment one, total play as well as object play was significantly more common in WL whereas locomotor and social play was more common in RJF. In experiment two, total play was significantly more frequent in commercially hatched chicks, despite that none of the sub-categories differed significantly between the groups. In conclusion, domestication as well as early stress does affect the occurrence of play in chickens, but the effects are complex and require further research.
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| 22. |
- Garnham, Laura, 1988-
(author)
-
Causes and Consequences of Impulsivity in Red Junglefowl
- 2022
-
Doctoral thesis (other academic/artistic)abstract
- Throughout the animal kingdom, animals vary in cognition (i.e., how they acquire, process, store, and act on environmental information). Yet, the causes and consequences of this variation are currently unclear. Inhibitory control is one such aspect of cognition that typically varies between individuals within all species investigated. Variation in inhibitory control underlies variation in impulsivity (i.e., the tendency to act without planning or considering the consequences). The causes and consequences of variation in impulsivity are, themselves, rarely explored, despite that these may have important ecological and evolutionary implications. My thesis (spanning 5 papers), therefore, aimed to fill some of these gaps by taking a holistic approach and investigating causes and consequences of variation in impulsivity (specifically, impulsive action and persistence measured in a detour task) in red junglefowl (Gallus gallus) males and females, chicks and adults. The red junglefowl was an ideal species for this investigation. Firstly, they show individual variation in impulsivity throughout their lives. They are also typically food motivated, and easily habituated to handling and new situations, which means they commonly willingly participate in behavioural and cognitive tests. Furthermore, they are precocial, which means that they can be hatched and raised without mothers, thus reducing parental effects. Finally, the large, accumulated knowledge of red junglefowl behaviour and cognition aids interpretations regarding this. As differences in experience early in life have been found to affect impulsivity, papers I and II empirically explored whether variation in two previously uninvestigated experiences in early life (exposure to enrichment, and social group size, respectively) influenced impulsivity. The dopaminergic and serotonergic systems are important signalling systems in the brain, which have been found to link to impulsivity in other species. Therefore, in paper I, I also explored if variation in impulsive action and persistence was connected to variation in dopaminergic or serotonergic gene expression. As impulsivity links to inhibitory control, in looking at the effect of group size on impulsivity, paper II explored the hypotheses that social environment affects cognition (e.g., that social environments which are assumed to be more cognitively demanding will lead to better cognitive performance, a.k.a., the social intelligence hypothesis). To uncover potential mechanisms by which group size could affect impulsivity, besides from variation in cognitive demand, paper II also investigated if behaviours that could covary with group size linked to impulsivity. As emotional arousal has been linked to impulsivity, in another species, and impulsivity is implicated in welfare issues, paper III looked into how both positive and negative affective states (which can be used to measure welfare) related to impulsivity. Prior to my thesis, whether variation in impulsivity could potentially affect animal welfare was scarcely explored. To better understand the potential consequences of impulsivity, and, thus, how selection could act on impulsivity, papers IV and V looked at potential implications of variation in impulsivity for social status (paper IV and V), foraging efficiency, and risk taking (paper V). My results showed that impulsivity could be consistent over time periods of weeks (in chicks, paper II) to months (in adults, paper V). Thus, impulsivity describes a characteristic of the individual. However, individuals could still learn to become less impulsive (paper I). Exposure to enrichment in early life could affect how impulsively individuals behaved. Environmental enrichment increased impulsivity, as did cognitive enrichment to a greater degree (paper I). Impulsive action, and persistence, correlated somewhat with brain gene expression of dopaminergic and serotonergic genes (DRD1, TPH; paper I). The social group size individuals experimentally experienced in early life did not affect their impulsivity (paper II). However, variation in impulsivity was connected to variation in activity, boldness, neophobia, and stress (paper II). Further, more impulsive individuals had less negative, more positive, affective states, but only when they were young chicks, and not as older chicks or adults (paper VI). No links were found between impulsivity and social status (paper IV and V), foraging efficiency, or risk taking (paper V). Taken together, paper I suggests that underlying explanations to observed individual variation in impulsivity could include variation in early life experiences and in dopaminergic and serotonergic gene expression, while paper II suggests that impulsivity may not be influenced by social aspects early in life. Papers II and III demonstrate that variation in impulsivity can associate with variation in behaviours and affective states (though these associations may vary over ontogeny), with the latter finding implying that variation in impulsivity could have welfare implications. Papers IV and V indicate that variation in impulsivity may have limited consequences for individuals in contexts that could affect reproduction or survival. Thus, it may not necessarily be costly to individuals if they are more impulsive than others. This, in turn, could help explain why variation in inhibitory control exists, because limited consequences of variation could result in low selection against variation. Overall, through the investigations conducted in its 5 papers, my thesis improves our understanding the potential causes and consequences of variation in impulsivity. As impulsivity is underlain by an aspect of cognition (inhibitory control), in exploring the causes and consequences of variation in impulsivity, my thesis also provides knowledge on causes and consequences of individual variation in cognition.
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| 23. |
- Guerrero-Bosagna, Carlos, 1975-, et al.
(author)
-
Globalization, climate change, and transgenerational epigenetic inheritance: will our descendants be at risk?
- 2015
-
In: Clinical Epigenetics. - : BioMed Central. - 1868-7083 .- 1868-7075. ; 7:8
-
Journal article (peer-reviewed)abstract
- Transgenerational epigenetic inheritance has gained increased attention due to the possibility that exposure to environmental contaminants induce diseases that propagate across generations through epigenomic alterations in gametes. In laboratory animals,exposure to environmental toxicants such as fungicides, pesticides, or plastic compounds has been shown to produce abnormal reproductive or metabolic phenotypes that are transgenerationally transmitted. Human exposures to environmental toxicants have increased due to industrialization and globalization, as well as the incidence of diseases shown to be transgenerationally transmitted in animal models. This new knowledge poses an urgent call to study transgenerational consequences of current human exposures to environmental toxicants.
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| 24. |
- Guerrero-Bosagna, Carlos, et al.
(author)
-
Optimized method for methylated DNA immuno-precipitation
- 2015
-
In: MethodsX. - : Elsevier. - 1258-780X .- 2215-0161. ; 2, s. e432-e439
-
Journal article (peer-reviewed)abstract
- Methylated DNA immunoprecipitation (MeDIP) is one of the most widely used methods to evaluate DNA methylation on a whole genome scale, and involves the capture of the methylated fraction of the DNA by an antibody specific to methyl-cytosine. MeDIP was initially coupled with microarray hybridization to detect local DNA methylation enrichments along the genome. More recently, MeDIP has been coupled with next generation sequencing, which highlights its current and future applicability. In previous studies in which MeDIP was applied, the protocol took around 3 days to be performed. Given the importance of MeDIP for studies involving DNA methylation, it was important to optimize the method in order to deliver faster turnouts. The present article describes optimization steps of the MeDIP method. The length of the procedure was reduced in half without compromising the quality of the results. This was achieved by:• Reduction of the number of washes in different stages of the protocol, after a careful evaluation of the number of indispensable washes.• Reduction of reaction times for detaching methylated DNA fragments from the complex agarose beads:antibody.• Modification of the methods to purify methylated DNA, which incorporates new devices and procedures, and eliminates a lengthy phenol and chloroform:isoamyl alcohol extraction.
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| 25. |
- Gunnarsson, Ulrika, et al.
(author)
-
Mutations in SLC45A2 Cause Plumage Color Variation in Chicken and Japanese Quail
- 2007
-
In: Genetics. - : Oxford University Press (OUP). - 0016-6731 .- 1943-2631. ; 175:2, s. 867-877
-
Journal article (peer-reviewed)abstract
- S*S (Silver), S*N (wild type/gold), and S*AL (sex-linked imperfect albinism) form a series of alleles at the S (Silver) locus on chicken (Gallus gallus) chromosome Z. Similarly, sex-linked imperfect albinism (AL*A) is the bottom recessive allele at the orthologous AL locus in Japanese quail (Coturnix japonica). The solute carrier family 45, member 2, protein (SLC45A2), previously denoted membrane-associated transporter protein (MATP), has an important role in vesicle sorting in the melanocytes. Here we report five SLC45A2 mutations. The 106delT mutation in the chicken S*AL allele results in a frameshift and a premature stop codon and the corresponding mRNA appears to be degraded by nonsense-mediated mRNA decay. A splice-site mutation in the Japanese quail AL*A allele causes in-frame skipping of exon 4. Two independent missense mutations (Tyr277Cys and Leu347Met) were associated with the Silver allele in chicken. The functional significance of the former mutation, associated only with Silver in White Leghorn, is unclear. Ala72Asp was associated with the cinnamon allele (AL*C) in the Japanese quail. The most interesting feature concerning the SLC45A2 variants documented in this study is the specific inhibition of expression of red pheomelanin in Silver chickens. This phenotypic effect cannot be explained on the basis of the current, incomplete, understanding of SLC45A2 function. It is an enigma why recessive null mutations at this locus cause an almost complete absence of both eumelanin and pheomelanin whereas some missense mutations are dominant and cause a specific inhibition of pheomelanin production.
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| 26. |
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| 27. |
- Hedlund, Louise, 1987-, et al.
(author)
-
Can Early Environmental Enrichment Buffer Stress from Commercial Hatchery Processing in Laying Hens?
- 2022
-
In: Poultry. - : MDPI. - 2674-1164. ; 1:2, s. 125-137
-
Journal article (peer-reviewed)abstract
- Under commercial conditions, laying hen chicks are exposed to a range of stressful events immediately after hatch. Here, we studied whether environmental enrichment was able to reduce the stress sensitivity of these chicks. A total of 50 hatchery chicks (HC) and 50 control chicks (CC) were raised in enriched pens (E), while 53 HC + 53 CC were raised in standard non-enriched floor pens (NE). HC weighed less on day one, but there was no effect of hatchery treatment at later ages. HC were more pessimistic in a cognitive judgement bias test and emitted more distress calls when socially isolated, indicating that hatchery stress affected behaviour and stress sensitivity. However, enrichment did not affect the behaviour in any of these tests. We found no effects of hatchery stress in a novel environment, but indications that enrichment may have increased fearfulness of HC. The sensitivity of the hypothalamic-pituitary-adrenal (HPA) axis was reduced in HC-E compared to HC-NE, indicating that enrichment buffered the physiological stress sensitivity in HC; however, the opposite pattern was found in CC. In conclusion, our results show complex and somewhat contradictory effects on the ability of enrichment to buffer the consequences of stress in commercial hatcheries.
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| 28. |
- Hedlund, Louise, 1987-
(author)
-
Effects of commercial hatchery processing on behaviour and welfare of laying hens
- 2022
-
Doctoral thesis (other academic/artistic)abstract
- Around the world, more than 76.7 million tons of eggs are consumed every year. To meet this demand, billions of laying hen chicks are produced under highly industrial circum-stances. These chicks are hatched in commercial hatcheries for laying hens in a presumably stressful environment, which might affect their welfare and production later in life. When the eggs arrive to the hatchery, they are inserted in large cabinet incubators that can hold approximately 60 000 eggs. The incubators are calibrated for optimal hatchability which includes turning of the eggs as well as fluctuating temperature and humidity over the day. This is regulated by fans whose purpose consists of removing heat and circulating the air in the incubators. However, the drawback of these fans is that their noise levels exceed 90 dB, which is equal to the sound of a passing train. After 19 days, the eggs are moved to a hatcher for the last days of incubation, in which they are exposed to formaldehyde for disinfection purposes. The eggs hatch after 21 days of incubation but are kept in the hatcher for an additional day to maximize hatchability rate. After removal from the hatcher, the racks with chicks are tilted onto a conveyer belt and separated from the shells. The chicks are then conveyed to a sex-sorting station where the males are dis-carded, and the females are further processed to a vaccination station. Once vaccinated, the animals are automatically counted and packed in transport boxes which are loaded onto a truck and transported to rearing farms. The aim of this thesis was to investigate if and how the chickens are short- and long-term affected by this hatchery procedure, including incubation and transportation, and how this might affect their welfare. In all experiments, we have compared commercial hatchery incubated, hatched, processed, and transported White Leghorn chicks (hatchery chicks, HC) with chicks incubated and hatched in a calm environment, and gently placed in their home pens directly after hatch (control chicks, CC). In all experiments, HC and CC were from the same parental stock and kept in separate but identical pens. In paper I, we blood sampled the chicks before and after the hatchery handling to evaluate stress hormone levels (CORT) in the hatchery. The HC had significantly higher CORT levels than the CC had at a corresponding time point, which implies that the hatchery treatment is a highly stressful experience. Our results of behaviour, HPA-axis sensitivity, and feather damages showed that the commercial hatchery treatment has a long-lasting overall negative effect on the animals up to at least 20 weeks of age. In paper II, we aimed to compare chicks incubated, hatched, and sorted at the hatchery, with chicks incubated and hatched at the hatchery who were not sorted, to distinguish the stress effects of the actual conveying and handling. We could not find any major differences between the groups and concluded that the most stressful part in the commercial hatchery seems to be the incubation and hatching, potentially due to the high noise levels and formaldehyde exposure. In paper III, we investigated possible welfare implications of the hatchery procedure by using a cognitive judgement bias (CJB) test that is used to measure optimism/pessimism in animals. In general, pessimistic animals perceive the same environment as more negative than optimistic animals, hence, this has a great impact on their welfare. When testing HC and CC in a CJB test, we could see that HC were consistently more pessimistic than CC, during 1st, but also during 10th week of age. This means that the hatchery treatment has a long-lasting effect on the cognitive state of the animals, implying the animals exposed to this have a poorer welfare. In paper IV, we investigated possible effects of the hatchery treatment on production parameters. We found that HC weighed less, and laid fewer and smaller eggs than CC. HC performed more feather pecking behaviour before sexual maturity, although the feather condition after sexual maturity showed the opposite pattern. We conclude that there seems to be an effect of the hatchery treatment on traits relevant for the industry, and that this effect seems to be overall negative. In the last study, paper V, we investigated if it is possible to buffer the hatchery stress with environmental enrichment. The enriched chicks were kept in a complex environment and imprinted on, and provided with, a stuffed mother hen. We could see a supressed physiological stress reaction to restraint in enriched HC, however, the opposite pattern was shown in CC. We found no other effects of environmental enrichment, how-ever, an overall difference between the groups where HC were more pessimistic and fearful than CC, which is in line with our previous results. In conclusion, the hatchery procedure including incubation, hatching, conveying, sex sorting, vaccination, and transport seems to have an overall long-lasting negative effect on chicks, where HC are more fearful and pessimistic, have a more sensitive HPA-axis, show more feather pecking behaviour, and are negatively affected with regard to traits relevant to the industry. I think that these results are highly relevant, not only for the industry, but also for the welfare of the world’s most common farm animal.
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| 29. |
- Hedlund, Louise, 1987-, et al.
(author)
-
Effects of stress during commercial hatching on growth, egg production and feather pecking in laying hens
- 2022
-
In: PLOS ONE. - San Francisco, CA, United States : Public Library of Science. - 1932-6203. ; 17:1
-
Journal article (peer-reviewed)abstract
- Every year, billions of egg layer chicks around the world are hatched under highly stressful, industrial circumstances. Here, it is investigated how the stressful procedure in the commercial hatchery, including incubation, hatching, processing, and transport affects the chicks with regards to traits relevant for the egg production industry. These traits were compared to those of a control group hatched in a small incubator and handled gently och quietly in a quiet room without any processing and transport. The chicks were weighed at hatch and at eight additional time points: 4 days, 1 week (w), 2 w, 3 w, 5 w, 8 w, 20 w and 25 w of age. Feather pecking was studied at 15 w of age and damages to the feathers and injuries on the comb and wattle were assessed at 25 w of age. From 19 w of age, eggs were collected on three days per week, counted and weighed. Chicks from a commercial hatchery had a lower hatch weight than control chicks (p<0.001). At 20 w of age, the weight of the commercial hatched chicks was still numerically lower, although this did not reach statistical significance. Commercially hatched chicks tended to show more feather pecking behaviour at 15 w of age compared to control chicks (p<0.1), although feather condition at 25 w of age showed the opposite pattern. Regarding production, commercially hatched chickens laid fewer (p<0.05) and smaller (p<0.05) eggs than chicks hatched and handled under calm circumstances. From this experiment, it is concluded that the stressful experience in the commercial hatchery has an overall negative effect on traits relevant for the industry.
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| 30. |
- Höglund, Andrey, 1985-
(author)
-
Quantitative genetics of gene expression and methylation in the chicken
- 2020
-
Doctoral thesis (other academic/artistic)abstract
- In quantitative genetics the relationship between genetic and phenotypic variation is investigated. The identification of these variants can bring improvements to selective breeding, allow for transgenic techniques to be applied in agricultural settings and assess the risk of polygenic diseases. To locate these variants, a linkage-‐based quantitative trait locus (QTL) approach can be applied. In this thesis, a chicken intercross population between wild and domestic birds have been used for QTL mapping of phenotypes such as comb, body and brain size, bone density and anxiety behaviour. Gene expression QTL (eQTL) mapping was also done for tissues such as comb base, medullar bone, liver and brain. By overlapping eQTL and QTL, regions were identified associated with both the gene expression levels and the phenotypes simultaneously. In this way, a number of candidate genes, underlying variation in the above-‐mentioned phenotypes, were identified. Additionally, DNA methylation QTL (mQTL) mapping was done in the brain and the methylation landscape was assessed which indicated a decrease in methylation in the domestic breed. A small number of regions were identified which affected DNA methylation levels throughout the whole genome, so-‐called trans hotspots. Finally, DNA methylation levels were correlated with eQTL to assess the degree to which gene expression is affected by methylation, and with gene expression in general to assess the relationship between the transcriptome and methylome. Taken together, these studies link the differences observed in various phenotypes between two populations of chicken to genetic variants coupled with gene expression correlations suggesting candidate genes. DNA methylation levels were influential in regulating variation in gene expression, both positively and negatively, but gene expression was also influential in regulating the methylation level. Epi-‐alleles were identified which indicated genetic variants regulating methylation levels and gene expression levels either as the causal variant or in close linkage.
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| 31. |
- Höglund, Andrey, 1985-, et al.
(author)
-
The methylation landscape and its role in domestication and gene regulation in the chicken
- 2020
-
In: Nature Ecology & Evolution. - : Springer Nature. - 2397-334X. ; 4, s. 1713-1724
-
Journal article (peer-reviewed)abstract
- Domestication is one of the strongest examples of artificial selection and has produced some of the most extreme within-species phenotypic variation known. In the case of the chicken, it has been hypothesized that DNA methylation may play a mechanistic role in the domestication response. By inter-crossing wild-derived red junglefowl with domestic chickens, we mapped quantitative trait loci for hypothalamic methylation (methQTL), gene expression (eQTL) and behaviour. We find large, stable methylation differences, with 6,179 cis and 2,973 trans methQTL identified. Over 46% of the trans effects were genotypically controlled by five loci, mainly associated with increased methylation in the junglefowl genotype. In a third of eQTL, we find that there is a correlation between gene expression and methylation, while statistical causality analysis reveals multiple instances where methylation is driving gene expression, as well as the reverse. We also show that methylation is correlated with some aspects of behavioural variation in the inter-cross. In conclusion, our data suggest a role for methylation in the regulation of gene expression underlying the domesticated phenotype of the chicken.
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| 32. |
- Jensen, Per, 1956-
(author)
-
2 - Genetics and genomics of animal welfare
- 2018
-
In: Advances in Agricultural Animal Welfare. - : Woodhead Publishing. - 9780081012154 ; , s. 25-48
-
Book chapter (other academic/artistic)abstract
- Behavior and welfare are closely dependent on the underlying genetics, yet so far this connection has been poorly investigated. Using domestication as a model, this chapter outlines the fundamentals of genetic inheritance, and explains some central concepts such as linkage, pleiotropy, epistasis, and heritability. It then outlines the essential approaches to finding single genes associated with specific behavioral- and welfare-related traits. These are split into top-down and bottom-up approaches, depending on whether the phenotype or genotype is the starting point for analysis. Finally, the novel field of epigenetics and its importance for welfare science are covered.
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| 33. |
- Jensen, Per, 1956-
(author)
-
Adding ‘epi-’ to behaviour genetics: implications for animaldomestication
- 2015
-
In: Journal of Experimental Biology. - : The Company if Biologists Ltd. - 0022-0949 .- 1477-9145. ; 218:1-5, s. 32-40
-
Research review (peer-reviewed)abstract
- In this review, it is argued that greatly improved understanding ofdomestication may be gained from extending the field of behaviourgenetics to also include epigenetics. Domestication offers aninteresting framework of rapid evolutionary changes caused by welldefinedselection pressures. Behaviour is an important phenotype inthis context, as it represents the primary means of response toenvironmental challenges. An overview is provided of the evidencefor genetic involvement in behavioural control and the presently usedmethods for finding so-called behaviour genes. This shows thatevolutionary changes in behaviour are to a large extent correlated tochanges in patterns of gene expression, which brings epigenetics intothe focus. This area is concerned with the mechanisms controllingthe timing and extent of gene expression, and a lot of focus has beenplaced on methylation of cytosine in promoter regions, usuallyassociated with genetic downregulation. The review considers theavailable evidence that environmental input, for example stress, canmodify methylation and other epigenetic marks and subsequentlyaffect behaviour. Furthermore, several studies are reviewed,demonstrating that acquired epigenetic modifications can be inheritedand cause trans-generational behaviour changes. In conclusion,epigenetics may signify a new paradigm in this respect, as it showsthat genomic modifications can be caused by environmental signals,and random mutations in DNA sequence are therefore not the onlysources of heritable genetic variation.
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| 34. |
- Jensen, Per, 1956-
(author)
-
Att leva med hund : en guide till dina hundår
- 2020
-
Book (pop. science, debate, etc.)abstract
- Med humor, värme och en stor kärlek till hundar förmedlar Per Jensen det senaste om hur våra fyrbenta vänner fungerar i olika faser av livet och hur vi kan använda de nya rönen för att få en lycklig samvaro.
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| 35. |
- Jensen, Per, 1956-
(author)
-
Behavior Genetics and the Domestication of Animals
- 2014
-
In: Annual Review of Animal Biosciences. - : Annual Reviews. - 2165-8102 .- 2165-8110. ; 2, s. 85-104
-
Journal article (peer-reviewed)abstract
- Across species, a similar suite of traits tends to develop in response todomestication, including modifications in behavior. Reduced fearand increased stress tolerance were central in early domestication,and many domestication-related behaviors may have developed astraits correlated to reduced fear.Genetic mechanisms involved in domesticationof behavior can be investigated by using top-down orbottom-up approaches, either starting from the behavior variationand searching for underlying genes or finding selected loci and thenattempting to identify the associated phenotypes. Combinations ofthese approaches have proven powerful, and examples of resultsfrom such studies are presented and discussed. This includes loci associatedwith tameness in foxes and dogs, as well as loci correlatedwith reduced aggression and increased sociality in chickens. Finally,some examples are provided on epigenetic mechanisms in behavior,and it is suggested that selection of favorable epigenetic variantsmayhave been an important mechanism in domestication.
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| 36. |
- Jensen, Per, 1956-
(author)
-
Behaviour epigenetics – The connection between environment, stress and welfare
- 2014
-
In: Applied Animal Behaviour Science. - : Elsevier. - 0168-1591 .- 1872-9045. ; 157, s. 1-7
-
Journal article (peer-reviewed)abstract
- Epigenetics refers to chemical modifications of DNA, which do not change the base-pairsequence. This involves, for example, methylation of cytosine and different alterations inhistone chemistry. Such modifications affect how genes are expressed and can occur as aresponse to stress, mediated by steroid hormones. Hence, the coordination of how genesare expressed, the orchestration of the genome so to say, responds dynamically to environ-mental challenges. In this selective review, the evidence in support of such mechanismsis discussed. Data show that epigenetic mechanisms can be affected by stress in differentlife phases, even prenatally, and this can cause long-term modifications of behaviour andstress susceptibility. Several studies show that such effects can even persist into cominggenerations. Research on chickens demonstrates that chronic, as well as brief events ofstress cause transgenerationally stable changes of brain gene expression, behaviour andHPA-axis sensitivity. Evidence is also reviewed, suggesting that epigenetic variation mayhave been a substrate for selection during domestication. It is concluded that the mainresearch challenge for the future is to understand the gene × epigenetics × environmentinteraction, and incorporate this into the field of animal welfare.
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| 37. |
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| 38. |
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| 39. |
- Jensen, Per, 1956-
(author)
-
Domestication-From behaviour to genes and back again
- 2006
-
In: Applied Animal Behaviour Science. - : Elsevier BV. - 0168-1591 .- 1872-9045. ; 97:1, s. 3-15
-
Journal article (peer-reviewed)abstract
- During domestication, animals have adapted with respect to behaviour and an array of other traits. This tends to give rise to a specific domestication phenotype, involving similar changes in colour, size, physiology and behaviour among different species. Hence, domestication offers a model for understanding the genetic mechanisms involved in the trade-off between behaviour and other traits in response to selection. We compared the behaviour and other phenotypic traits of junglefowl and white leghorn layers, selected for egg production (and indirectly for growth). To examine the genetic mechanisms underlying the domestication-related differences, we carried out a genome scan for quantitative trait loci (QTLs) affecting behaviour and production traits in F2-birds of a junglefowl×white leghorn intercross. Several significant or suggestive QTLs for different production traits were located and some of these coincided with QTLs for behaviour, suggesting that QTLs with pleiotropic effects (or closely linked QTLs) may be important for the development of domestication phenotypes. Two genes and their causative mutations for plumage colouration have been identified, and one of these has a strong effect on the risk of being a victim of feather pecking, a detrimental behaviour disorder. It is likely that fast and large evolutionary changes in many traits simultaneously may be caused by mutations in regulatory genes, causing differences in gene expression orchestration. Modern genomics paired with analysis of behaviour may offer a route for understanding the relation between behaviour and production and predicting possible side-effects of breeding programs.
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| 40. |
- Jensen, Per, 1956-, et al.
(author)
-
Feather pecking in chickens is genetically related to behavioural and developmental traits.
- 2005
-
In: Physiology & behavior. - : Elsevier BV. - 0031-9384 .- 1873-507X. ; 86:1-2, s. 52-60
-
Journal article (peer-reviewed)abstract
- Feather pecking (FP) is a detrimental behaviour in chickens, which is performed by only some individuals in a flock. FP was studied in 54 red junglefowl (ancestor of domestic chickens), 36 White Leghorn laying hens, and 762 birds from an F(2)-intercross between these two lines. From all F(2)-birds, growth and feed consumption were measured. Age at sexual maturity and egg production in females, and corticosterone levels in males were also measured. From 333 F(2)-birds of both sexes, and 20 parental birds, body composition with respect to bone mineral content, muscle and fat was obtained by post-mortem examinations using Dual X-Ray Absorptiometry (DXA). In femurs of the same birds, the bone density and structure were analysed using DXA and Peripheral Quantitative Computerized Tomography (pQCT), and a biomechanical analysis of bone strength was performed. Furthermore, plumage condition was determined in all birds as a measure of being exposed to feather pecking. Using 105 DNA-markers in all F(2)-birds, a genome-wide scan for Quantitative Trait Loci (QTL), associated with the behaviour in the F(2)-generation was performed. FP was at least as frequent in the red junglefowl as in the White Leghorn strain studied here, and significantly more common among females both in the parental strains and in the F(2)-generation. In the F(2)-birds, FP was phenotypically linked to early sexual maturation, fast growth, weak bones, and, in males, also high fat accumulation, indicating that feather peckers have a different resource allocation pattern. Behaviourally, F(2) feather peckers were more active in an open field test, in a novel food/novel object test, and in a restraint test, indicating that feather pecking might be genetically linked to a proactive coping strategy. Only one suggestive QTL with a low explanatory value was found on chromosome 3, showing that many genes, each with a small effect, are probably involved in the causation of feather pecking. There were significant effects of sire and dam on the risk of being a victim of feather pecking, and victims grew faster pre- and post-hatching, had lower corticosterone levels and were less active in a restraint test. Hence, a wide array of behavioural and developmental traits were genetically linked to FP.
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| 41. |
- Jensen, Per, 1956-, et al.
(author)
-
Genetics and genomics of animal behaviour and welfare-Challenges and possibilities
- 2008
-
In: Applied Animal Behaviour Science. - : Elsevier BV. - 0168-1591 .- 1872-9045. ; 113:4, s. 383-403
-
Journal article (peer-reviewed)abstract
- Traditionally, the contribution of applied ethology to animal welfare science has concentrated on understanding the reactions of animals to their housing conditions. Domestication has had small effects on fundamental aspects of animal behaviour, and therefore, the needs of present day domesticated animals are closely related to the evolutionary history of the ancestors. However, the last decades have seen an unprecedented intensification of selection for increased production, which has significant side-effects on behaviour and welfare. Understanding the nature of such side-effects have therefore emerged as a central problem to animal welfare science. Modern genetics and genomics offer tools for such research, and this review outlines some of the available methods and how these have been, and could be, used to enrich animal welfare science. An outline is given on traditional genetic selection methods applied on behaviour and welfare related variables. Significant improvements in levels of fearfulness and abnormal behaviour have been achieved by selecting populations against these traits. As a next step, it is necessary to map the loci involved in affecting these traits, and quantitative trait locus (QTL) analysis have been used for this. An overview of QTL-analyses of welfare related traits in different species is given, including how this analysis has provided new insights into the genetic architecture of the stress response. Beyond allelic differences, which can be mapped with QTL-analysis, welfare related biological responses may be mediated by acquired modifications in expression levels of genes and gene complexes. This can be analysed with cDNA microarray technology, and a review of relevant work in this respect is given. Many of the changes in genetic control mechanisms observed during selection are results of evolutionary responses, for example related to sexual selection. An overview with a genetic perspective is provided of this often neglected aspect of domestication in relation to animal welfare problems. It is concluded that modern selection of farm animals pose a serious challenge to animal welfare, but also previously unknown possibilities to improve welfare by using high precision breeding techniques. © 2008 Elsevier B.V. All rights reserved.
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| 42. |
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| 43. |
- Jensen, Per, 1956-
(author)
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Hunden som skäms : myt eller sanning?
- 2014
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Book (other academic/artistic)abstract
- Hundar har en unik förmåga att förstå och kommunicera med oss människor, utvecklad under årtusenden av nära samliv. Faktum är att de på många sätt förstår oss bättre än vad vi själva gör. Under senare år har forskarna på allvar börjat glänta på dörren till hundarnas inre liv. Vi har lärt oss att deras tankar och känslor framförallt kretsar runt en sak: relationen till människor.Här kan du läsa om de nya rönen kring hundarnas intelligens och känsloliv. Skäms de verkligen när de gjort något förbjudet? Har de sinne för rättvisa och blir de svartsjuka? Hur ser deras tidsuppfattning ut? Hur mycket förstår de av vårt språk? De nya insikterna i hundarnas innersta tankar gör det svårt att någonsin betrakta dem på samma sätt igen.
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| 44. |
- Jensen, Per, 1956-
(author)
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Hundens hemligheter : om vanliga men oförklarliga beteenden
- 2023
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Book (pop. science, debate, etc.)abstract
- Har du undrat varför hundar gärna äter märkliga saker, som gräs eller bajs? Eller varför de rullar sig i stinkande högar och lägger så mycket tid på att leka och sova? På ett lättläst och pedagogiskt sätt tar Per Jensen upp dessa och en rad andra hittills obesvarade gåtor och presenterar, med humor och en stor kärlek till hundar, hur vetenskapen försökt lösa dem.[Bokinfo]
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| 45. |
- Jensen, Per, 1956-
(author)
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Hundens språk och tankar
- 2021
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Book (pop. science, debate, etc.)abstract
- Det är svårt att tänka sig ett mänskligt liv utan hundar! Sedan vi levde som jägare och samlare har hunden följt oss människor. Per Jensen, professor i etologi, har skrivit en bok om hundens beteende, språk och tankeförmåga och beskriver pedagogiskt hur kunskapsläget är idag. Ny fakta blir här tillgänglig för en intresserad allmänhet.
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| 46. |
- Jensen, Per, 1956-
(author)
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Hur smart är din hund? : praktiska övningar att göra hemma
- 2015
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Book (pop. science, debate, etc.)abstract
- Vad tänker din hund egentligen? Förstår den vad du säger? Är den empatisk och har den känsla för rättvisa? Hundars speciella intelligens handlar om att kommunicera med oss människor, och etologer beteendeforskare har på senare år kartlagt hundens inre liv med hjälp av olika vetenskapliga undersökningar.I den här boken har Per Jensen anpassat en rad av dessa experiment till enkla test som du kan göra själv tillsammans med din hund. Boken är en handbok för hemmaetologen och de olika försöken kan enkelt byggas ut till mer omfattande experiment. Och det bästa av allt är att din hund och du får några roliga stunder ihop och lär känna varandra bättre!
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| 47. |
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| 48. |
- Jensen, Per, 1956-
(author)
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Transgenerational epigenetic effects on animal behaviour
- 2013
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In: Progress in Biophysics and Molecular Biology. - : Elsevier. - 0079-6107 .- 1873-1732. ; 113:3, s. 447-454
-
Research review (peer-reviewed)abstract
- Over the last decade a shift in paradigm has occurred with respect to the interaction between environmentand genes. It is now clear that animal genomes are regulated to a large extent as a result of inputfrom environmental events and experiences, which cause short- and long-term modifications in epigeneticmarkings of DNA and histones. In this review, the evidence that such epigenetic modificationscan affect the behaviour of animals is explored, and whether such acquired behaviour alterations cantransfer across generation borders. First, the mechanisms by which experiences cause epigenetic modificationsare examined. This includes, for example, methylation of cytosine in CpG positions and acetylationof histones, and studies showing that this can be modified by early experiences. Secondly, theevidence that specific modifications in the epigenome can be the cause of behaviour variation isreviewed. Thirdly, the extent to which this phenotypically active epigenetic variants can be inheritedeither through the germline or through reoccurring environmental conditions is examined. A particularlyinteresting observation is that epigenetic modifications are often linked to stress, and may possibly bemediated by steroid effects. Finally, the idea that transgenerationally stable epigenetic variants may serveas substrates for natural selection is explored, and it is speculated that they may even predispose fordirected, non-random mutations.
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| 49. |
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| 50. |
- Johnsson, Martin, et al.
(author)
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A sexual ornament in chickens is affected by pleiotropic alleles at HAO1 and BMP2, selected during domestication.
- 2012
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In: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404 .- 1553-7390. ; 8:8
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Journal article (peer-reviewed)abstract
- Domestication is one of the strongest forms of short-term, directional selection. Although selection is typically only exerted on one or a few target traits, domestication can lead to numerous changes in many seemingly unrelated phenotypes. It is unknown whether such correlated responses are due to pleiotropy or linkage between separate genetic architectures. Using three separate intercrosses between wild and domestic chickens, a locus affecting comb mass (a sexual ornament in the chicken) and several fitness traits (primarily medullary bone allocation and fecundity) was identified. This locus contains two tightly-linked genes, BMP2 and HAO1, which together produce the range of pleiotropic effects seen. This study demonstrates the importance of pleiotropy (or extremely close linkage) in domestication. The nature of this pleiotropy also provides insights into how this sexual ornament could be maintained in wild populations.
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