| 1. |
- Atikuzzaman, Mohammad, et al.
(författare)
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Mating induces the expression of immune- and pH-regulatory genes in the utero-vaginal junction containing mucosal sperm-storage tubuli of hens
- 2015
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Ingår i: Reproduction. - : Bioscientifica. ; 150:6, s. 473-483
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Tidskriftsartikel (refereegranskat)abstract
- The female chicken, as with other species with internal fertilization, can tolerate the presence of spermatozoa within specialized sperm-storage tubuli (SST) located in the mucosa of the utero-vaginal junction (UVJ) for days or weeks, without eliciting an immune response. To determine if the oviduct alters its gene expression in response to sperm entry, segments from the oviduct (UVJ, uterus, isthmus, magnum and infundibulum) of mated and unmated (control) hens, derived from an advanced inter-cross line between Red Junglefowl and White Leghorn, were explored 24 h after mating using cDNA microarray analysis. Mating shifted the expression of fifteen genes in the UVJ (53.33% immune-modulatory and 20.00% pH-regulatory) and seven genes in the uterus, none of the genes in the latter segment overlapping the former (with the differentially expressed genes themselves being less related to immune-modulatory function). The other oviductal segments did not show any significant changes. These findings suggest sperm deposition causes a shift in expression in the UVJ (containing mucosal SST) and the uterus for genes involved in immune-modulatory and pH-regulatory functions, both relevant for sperm survival in the hen's oviduct.
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| 2. |
- Bakovic, Vid, et al.
(författare)
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The genomics of phenotypically differentiated Asellus aquaticus cave, surface stream and lake ecotypes
- 2021
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Ingår i: Molecular Ecology. - : Wiley-Blackwell. - 0962-1083 .- 1365-294X. ; 30:14, s. 3530-3547
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Tidskriftsartikel (refereegranskat)abstract
- Organisms well suited for the study of ecotype formation have wide distribution ranges, where they adapt to multiple drastically different habitats repeatedly over space and time. Here we study such ecotypes in a Crustacean model, Asellus aquaticus, a commonly occurring isopod found in freshwater habitats as diverse as streams, caves and lakes. Previous studies focusing on cave vs. surface ecotypes have attributed depigmentation, eye loss and prolonged antennae to several south European cave systems. Likewise, surveys across multiple Swedish lakes have identified the presence of dark-pigmented "reed" and light-pigmented "stonewort" ecotypes, which can be found within the same lake. In this study, we sequenced the first draft genome of A. aquaticus, and subsequently use this to map reads and call variants in surface stream, cave and two lake ecotypes. In addition, the draft genome was combined with a RADseq approach to perform a quantitative trait locus (QTL) mapping study using a laboratory bred F-2 and F-4 cave x surface intercross. We identified genomic regions associated with body pigmentation, antennae length and body size. Furthermore, we compared genome-wide differentiation between natural populations and found several genes potentially associated with these habitats. The assessment of the cave QTL regions in the light-dark comparison of lake populations suggests that the regions associated with cave adaptation are also involved with genomic differentiation in the lake ecotypes. These demonstrate how troglomorphic adaptations can be used as a model for related ecotype formation.
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| 3. |
- Fogelholm, Jesper, 1986-, et al.
(författare)
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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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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Fogelholm, Jesper, et al.
(författare)
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Genetical Genomics of Tonic Immobility in the Chicken
- 2019
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Ingår i: Genes. - : MDPI. - 2073-4425. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- Identifying the molecular mechanisms of animal behaviour is an enduring goal for researchers. Gaining insight into these mechanisms enables us to gain a greater understanding of behaviour and their genetic control. In this paper, we perform Quantitative Trait Loci (QTL) mapping of tonic immobility behaviour in an advanced intercross line between wild and domestic chickens. Genes located within the QTL interval were further investigated using global expression QTL (eQTL) mapping from hypothalamus tissue, as well as causality analysis. This identified five candidate genes, with the genes PRDX4 and ACOT9 emerging as the best supported candidates. In addition, we also investigated the connection between tonic immobility, meat pH and struggling behaviour, as the two candidate genes PRDX4 and ACOT9 have previously been implicated in controlling muscle pH at slaughter. We did not find any phenotypic correlations between tonic immobility, struggling behaviour and muscle pH in a smaller additional cohort, despite these behaviours being repeatable within-test.
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| 5. |
- Fogelholm, Jesper, 1986-
(författare)
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Genomics and Transcriptomics of Behaviour and Plumage Colouration
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim throughout this thesis has been to investigate the underlying genetics of behaviours and feather colour and plumage patterns by using chickens as a model organism. Chickens are extremely important as a food source, both in terms of egg, as well as meat production. As such there is a large research interest for them, and they provide an excellent model to study the effects of domestication and evolution, since the ancestor to our domestic breeds the Red Junglefowl can still be found living freely in the wild. This allows us to set up long term crossing experiments where we can harness the power of recombination events and genome wide sequencing to perform genome wide mapping studies. I also want to take the opportunity to integrate the results from all of my work and consider it in perspective of the domestication syndrome.In Paper I we investigated the Social Reinstatement behaviour which combines aspects of sociality and anxiousness. We detected several QTL and some overlap with Open Field behaviour from previous work within the group. By combining genomic and transcriptomic methods three strong candidate genes were found: TTRAP, ACOT9 and PRDX4. In Paper II Tonic Immobility, another classic behaviour was examined. Once more there was some overlap with the QTL regions discovered in earlier work, and it turns out that two of the most well supported candidate genes for Tonic Immobility is ACOT9 and PRDX4. These two genes had also been implicated with a pH dependent meat quality trait. Therefore, we conducted experiments in an additional smaller scale test cohort to investigate any potential link between the two traits. Following statistical multiple testing corrections, no significant association was found.The remaining papers in the thesis investigated different types of feather patterning and colour. In Paper III we determined that the underlying genetic mechanism behind the striped appearance of the sex-linked barring feathers is likely caused by cyclic depletion and renewal of the pigment producing melanocyte cells during feather growth, which is a consequence of specific mutations in the gene CDKN2A. Paper IV took a quantitative approach to colour by measuring and quantifying the pheomelanic colour ranging from dark red to yellow. We identified five main candidate genes for the intensity of red colouration, CREBBP, WDR24, ARL8A, PHLDA3 and LAD1. They are all regulated by a trans-acting eQTL located within the QTL region previously associated with behaviours in Paper I and Paper II.Finally, in Paper V we turned our attention from pigment-based colour traits to an iridescent structural colour. Here we followed up the QTL mapping performed in our F8 lab intercross with a Genome Wide Association Study in two feral populations from the islands of Kauai and Bermuda. RNA-sequencing was then performed in selected individuals from both feral populations in addition to individuals from the F3 generation of our domestic x wild intercross. The main region of interest is located between 17.4 -17.5Mb on chromosome Z, with the main candidate genes being MAP3K1, Zinc finger RNA binding protein 2, and Zinc finger protein. After integrating and viewing the results from the work conducted as a part of this thesis from the perspective of the Domestication Syndrome, I have found that there are a lot of potential connections between the traits that I have studied. For instance, the same QTL region on chromosome 10 is detected in association with the behaviour traits in Paper I and Paper II and the quantitative colour trait in Paper IV. I believe that the domestication syndrome is caused by the underlying functional arrangement of the genome, which causes correlated responses in nearby genes and their associated traits, when selective forces such as domestication are applied on the primary trait.
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| 6. |
- Henriksen, Rie, et al.
(författare)
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Intra-Individual Behavioural Variability: A Trait under Genetic Control
- 2020
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 21:21
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Tidskriftsartikel (refereegranskat)abstract
- When individuals are measured more than once in the same context they do not behave in exactly the same way each time. The degree of predictability differs between individuals, with some individuals showing low levels of variation around their behavioural mean while others show high levels of variation. This intra-individual variability in behaviour has received much less attention than between-individual variability in behaviour, and very little is known about the underlying mechanisms that affect this potentially large but understudied component of behavioural variation. In this study, we combine standardized behavioural tests in a chicken intercross to estimate intra-individual behavioural variability with a large-scale genomics analysis to identify genes affecting intra-individual behavioural variability in an avian population. We used a variety of different anxiety-related behavioural phenotypes for this purpose. Our study shows that intra-individual variability in behaviour has a direct genetic basis that is largely unique compared to the genetic architecture for the standard behavioural measures they are based on (at least in the detected quantitative trait locus). We identify six suggestive candidate genes that may underpin differences in intra-individual behavioural variability, with several of these candidates having previously been linked to behaviour and mental health. These findings demonstrate that intra-individual variability in behaviour appears to be a heritable trait in and of itself on which evolution can act.
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| 7. |
- Höglund, Andrey, et al.
(författare)
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The genetic regulation of size variation in the transcriptome of the cerebrum in the chicken and its role in domestication and brain size evolution
- 2020
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Ingår i: BMC Genomics. - : BMC. - 1471-2164. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundLarge difference in cerebrum size exist between avian species and populations of the same species and is believed to reflect differences in processing power, i.e. in the speed and efficiency of processing information in this brain region. During domestication chickens developed a larger cerebrum compared to their wild progenitor, the Red jungle fowl. The underlying mechanisms that control cerebrum size and the extent to which genetic regulation is similar across brain regions is not well understood. In this study, we combine measurement of cerebrum size with genome-wide genetical genomics analysis to identify the genetic architecture of the cerebrum, as well as compare the regulation of gene expression in this brain region with gene expression in other regions of the brain (the hypothalamus) and somatic tissue (liver).ResultsWe identify one candidate gene that putatively regulates cerebrum size (MTF2) as well as a large number of eQTL that regulate the transcriptome in cerebrum tissue, with the majority of these eQTL being trans-acting. The overall regulation of gene expression variation in the cerebrum was markedly different to the hypothalamus, with relatively few eQTL in common. In comparison, the cerebrum tissue shared more eQTL with a distant tissue (liver) than with a neighboring tissue (hypothalamus).ConclusionThe candidate gene for cerebrum size (MTF2) has previously been linked to brain development making it a good candidate for further investigation as a regulator of inter-population variation in cerebrum size. The lack of shared eQTL between the two brain regions implies that genetic regulation of gene expression appears to be relatively independent between the two brain regions and suggest that coevolution between these two brain regions might be more functionally driven than developmental. These findings have relevance for current brain size evolution theories.
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| 8. |
- Höglund, Andrey, 1985-, et al.
(författare)
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The methylation landscape and its role in domestication and gene regulation in the chicken
- 2020
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Ingår i: Nature Ecology & Evolution. - : Springer Nature. - 2397-334X. ; 4, s. 1713-1724
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Johnsson, Martin, et al.
(författare)
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Genetical genomics of growth in a chicken model
- 2018
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Ingår i: BMC Genomics. - : BIOMED CENTRAL LTD. - 1471-2164. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- Background: The genetics underlying body mass and growth are key to understanding a wide range of topics in biology, both evolutionary and developmental. Body mass and growth traits are affected by many genetic variants of small effect. This complicates genetic mapping of growth and body mass. Experimental intercrosses between individuals from divergent populations allows us to map naturally occurring genetic variants for selected traits, such as body mass by linkage mapping. By simultaneously measuring traits and intermediary molecular phenotypes, such as gene expression, one can use integrative genomics to search for potential causative genes. Results: In this study, we use linkage mapping approach to map growth traits (N = 471) and liver gene expression (N = 130) in an advanced intercross of wild Red Junglefowl and domestic White Leghorn layer chickens. We find 16 loci for growth traits, and 1463 loci for liver gene expression, as measured by microarrays. Of these, the genes TRAK1, OSBPL8, YEATS4, CEP55, and PIP4K2B are identified as strong candidates for growth loci in the chicken. We also show a high degree of sex-specific gene-regulation, with almost every gene expression locus exhibiting sex-interactions. Finally, several trans-regulatory hotspots were found, one of which coincides with a major growth locus. Conclusions: These findings not only serve to identify several strong candidates affecting growth, but also show how sex-specificity and local gene-regulation affect growth regulation in the chicken.
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| 10. |
- Johnsson, Martin, et al.
(författare)
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Genetics and Genomics of Social Behavior in a Chicken Model
- 2018
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Ingår i: Genetics. - : GENETICS SOCIETY AMERICA. - 0016-6731 .- 1943-2631. ; 209:1, s. 209-221
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Tidskriftsartikel (refereegranskat)abstract
- The identification of genes affecting sociality can give insights into the maintenance and development of sociality and personality. In this study, we used the combination of an advanced intercross between wild and domestic chickens with a combined QTL and eQTL genetical genomics approach to identify genes for social reinstatement, a social and anxiety-related behavior. A total of 24 social reinstatement QTL were identified and overlaid with over 600 eQTL obtained from the same birds using hypothalamic tissue. Correlations between overlapping QTL and eQTL indicated five strong candidate genes, with the gene TTRAP being strongly significantly correlated with multiple aspects of social reinstatement behavior, as well as possessing a highly significant eQTL.
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