Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "hsv:(NATURVETENSKAP) hsv:(Biologiska vetenskaper) hsv:(Utvecklingsbiologi) "

Sökning: hsv:(NATURVETENSKAP) hsv:(Biologiska vetenskaper) hsv:(Utvecklingsbiologi)

Sortera/gruppera träfflistan
  • Fallahshahroudi, Amir, 1981- (författare)
  • Domestication Effects on the Stress Response in Chickens : Genetics, Physiology, and Behaviour
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt)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.
  • Bélteky, Johan (författare)
  • Chicken domestication : Effects of tameness on brain gene expression and DNA methylation
  • 2016
  • Doktorsavhandling (övrigt vetenskapligt)abstract
    • Domestication greatly increases phenotypic variation in a short time span, with selection for a single phenotype and a plethora of associated phenotypic changes as an outcome of the process. The domestication process influences the underlying genomic architecture of a species, and the success and speed of the process is likely influenced by it. The main aims of my thesis was to study how domestication affects the brain of chickens: specifically changes in morphology, gene expression, and DNA methylation. Differences in gene expression and DNA methylation between White Leghorn and Red Junglefowl chickens were mapped, and inheritance of these patterns were quantified, indicating a faithful transmission of breed-specific epigenetic markers. Selection on the behavioral trait fearfulness, generated high and low fearful lines of Red Junglefowl. Both the parental population and the fifth selected generation were used for the analyses in this thesis. One experiment studied morphological changes in the brain and other vital organs, and found that relative total brain size increased in high fearful birds, as a consequence of an increase in cerebral hemisphere size in high fearful birds and not in low fearful birds. Also, the relative heart, liver, spleen and testis size increased in high fearful birds, indicating correlated morphological changes with selection for fearfulness. Two additional experiments examined differential gene expression in the hypothalamus and the anterior cerebral hemisphere. The hypothalamus differed in expression of genes with reproductive and immunological functions, whilst the cerebral hemisphere differed in expression of genes related to social behaviors and neurological functions especially those upregulated in low fearful birds.  These results indicate the occurrence of tissue- and species-specific changes in gene expression as overlap with other domestication events were nearly nonexistent. A fourth experiment sought to associate the change in fear levels and gene expression differences with DNA methylation. Chromosomal regions with differential DNA methylation between high and low fearful birds were identified, and genes in these regions had annotated functions relevant to phenotypic differences between the selection lines. This thesis is the first to study the genetic alterations of domestication using the wild ancestor of an already domesticated species to repeat the domestication process selecting against fear of humans. The findings corroborate results from previous comparisons of wild and domestic animals, and further support the theory that rigorous selection for a behavioral trait can cause a cascade of genetic and epigenetic changes facilitating the domestication of a population.
  • Rice, William, et al. (författare)
  • Inter-locus antagonistic coevolution as an engine of speciation : assessment with hemiclonal analysis
  • 2005
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - Washington : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 102:Suppl. 1, s. 6527-6534
  • Tidskriftsartikel (refereegranskat)abstract
    • One of Ernst Mayr's legacies is the consensus that the allopatry model is the predominant mode of speciation in most sexually reproducing lineages. In this model, reproductive isolation develops as a pleiotropic byproduct of the genetic divergence that develops among physically isolated populations. Presently, there is no consensus concerning which, if any, evolutionary process is primarily responsible for driving the specific genetic divergence that leads to reproductive isolation. Here, we focus on the hypothesis that inter-locus antagonistic coevolution drives rapid genetic divergence among allopatric populations and thereby acts as an important “engine” of speciation. We assert that only data from studies of experimental evolution, rather than descriptive patterns of molecular evolution, can provide definitive evidence for this hypothesis. We describe and use an experimental approach, called hemiclonal analysis, that can be used in theDrosophila melanogaster laboratory model system to simultaneously screen nearly the entire genome for both standing genetic variation within a population and the net-selection gradient acting on the variation. Hemiclonal analysis has four stages: (i) creation of a laboratory “island population”; (ii) cytogenetic cloning of nearly genome-wide haplotypes to construct hemiclones; (iii) measurement of additive genetic variation among hemiclones; and (iv) measurement of the selection gradient acting on phenotypic variation among hemiclones. We apply hemiclonal analysis to test the hypothesis that there is ongoing antagonistic coevolution between the sexes in the D. melanogaster laboratory model system and then discuss the relevance of this analysis to natural systems.
  • Bahrampour, Shahrzad (författare)
  • Genetic mechanisms regulating proliferation and cell specification in the Drosophila embryonic CNS
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt)abstract
    • The central nervous system (CNS) consists of an enormous number of cells, and large cellular variance, integrated into an elaborate network. The CNS is the most complex animal organ, and therefore its establishment must be controlled by many different genetic programs. Considering the high level of complexity in the human CNS, addressing issues related to human neurodevelopment represents a major challenge. Since comparative studies have revealed that neurodevelopmental programs are well conserved through evolution, on both the genetic and functional levels, studies on invertebrate neurodevelopmental programs are often translatable to vertebrates. Indeed, the basis of our current knowledge about vertebrate CNS development has been greatly aided by studies on invertebrates, and in particular on the Drosophila melanogaster (fruit fly) model system.This thesis attempted to identify novel genes regulating neural cell specification and proliferation in the CNS, using the Drosophila model system. Moreover, I aimed to address how those genes govern neural progenitor cells (neuroblasts; NBs) to obtain/maintain their stemness identity and proliferation capacity, and how they drive NBs through temporal windows and series of programmed asymmetric division, which gradually reduces their stemness identity in favor of neural differentiation, resulting in appropriate lineage progression. In the first project, we conducted a forward genetic screen in Drosophila embryos, aimed at isolating genes involved in regulation of neural proliferation and specification, at the single cell resolution. By taking advantage of the restricted expression of the neuropeptide FMRFa in the last-born cell of the NB lineage 5-6T, the Ap4 neuron, we could monitor the entire lineage progression. This screen succeeded in identifying 43 novel genes controlling different aspects of CNS development. One of the genes isolated, Ctr9, displayed extra Ap4/FMRFa neurons. Ctr9 encodes a component of the RNA polymerase II complex Paf1, which is involved in a number of transcriptional processes. The Paf1C, including Ctr9, is highly conserved from yeast to human, and in the past couple of years, its importance for transcription has become increasingly appreciated. However, studies in the Drosophila system have been limited. In the screen, we isolated the first mutant of Drosophila Ctr9 and conducted the first detailed phenotypic study on its function in the Drosophila embryonic CNS. Loss of function of Ctr9 leads to extra NB numbers, higher proliferation ratio and lower expression of neuropeptides. Gene expression analysis identified several other genes regulated by Ctr9, which may explain the Ctr9 mutant phenotypes. In summary, we identified Ctr9 as an essential gene for proper CNS development in Drosophila, and this provides a platform for future study on the Drosophila Paf1C. Another interesting gene isolated in the screen was worniou (wor), a member of the Snail family of transcription factors. In contrast to Ctr9, whichdisplayed additional Ap4/FMRFa neurons, wor mutants displayed a loss of these neurons. Previous studies in our group have identified many genes acting to stop NB lineage progression, but how NBs are pushed to proliferate and generate their lineages was not well known. Since wor may constitute a “driver” of proliferation, we decided to study it further. Also, we identified five other transcription factors acting together with Wor as pro-proliferative in both NBs and their daughter cells. These “drivers” are gradually replaced by the previously identified late-acting “stoppers.” Early and late factors regulate each other and the cell cycle, and thereby orchestrate proper neural lineage progression.
  • Franz, F, et al. (författare)
  • The Transcriptional Regulation of FOXO Genes in Thyrocytes.
  • 2016
  • Ingår i: Hormone and Metabolic Research. - Stuttgart : Georg Thieme Verlag. - 0018-5043 .- 1439-4286. ; 48:9, s. 601-6
  • Tidskriftsartikel (refereegranskat)abstract
    • FOXO transcription factors are key regulators of DNA damage repair, proliferation and apoptosis in thyrocytes. Thyroid malignancies show impaired FOXO function. In this study, we investigated the transcriptional regulation of FOXO isoforms in thyroid epithelial cells. mRNA expression of FOXO isoforms (FOXO1, 3 and 4) was determined in FRTL-5 cells stimulated with different growth factors and H2O2. Furthermore, the impact of PI3K/AKT signalling on FOXO transcription was investigated in PI3K p110α mutant FRTL-5 cells and regulatory dependence of FOXO transcription on FOXO was studied in FRTL-5 cells with hFOXO3 overexpression. Finally, mRNA expression levels of FOXO isoforms were determined in human epithelial thyroid tumours. Growth factor deprivation induced transcription of FOXO1, 3 and 4, whereas insulin stimulation decreased FOXO1 and FOXO4 transcription in FRTL-5 cells. Inhibition of the PI3K/AKT cascade amplified FOXO1 and FOXO4 expression. In contrast, H2O2 and TSH did not influence FOXO transcription in thyrocytes. Overexpression of PI3K p110α inhibited FOXO3 and induced FOXO4 transcription. In human thyroid tumours, FOXO1 and FOXO3 mRNA levels were significantly downregulated in papillary thyroid carcinoma when compared to normal tissues. In contrast, follicular thyroid carcinomas showed significant upregulation of FOXO4 mRNA.In this paper, we demonstrate an influence of PI3K signalling on FOXO transcription in thyrocytes. Moreover, we show that thyroid cancers exhibit alterations in FOXO transcription besides the previously reported alterations in posttranslational FOXO3 regulation. These findings may add to the concept of targeting the PI3K pathway in advanced thyroid cancers.
  • Kuzhandaivel, Anujaianthi, et al. (författare)
  • Cilia-Mediated Hedgehog Signaling in Drosophila
  • 2014
  • Ingår i: Cell reports. - : Elsevier. - 2211-1247 .- 2211-1247. ; 7:3, s. 672-680
  • Tidskriftsartikel (refereegranskat)abstract
    • Cilia mediate Hedgehog (Hh) signaling in vertebrates and Hh deregulation results in several clinical manifestations, such as obesity, cognitive disabilities, developmental malformations, and various cancers. Drosophila cells are nonciliated during development, which has led to the assumption that cilia-mediated Hh signaling is restricted to vertebrates. Here, we identify and characterize a cilia-mediated Hh pathway in Drosophila olfactory sensory neurons. We demonstrate that several fundamental key aspects of the vertebrate cilia pathway, such as ciliary localization of Smoothened and the requirement of the intraflagellar transport system, are present in Drosophila. We show that Cos2 and Fused are required for the ciliary transport of Smoothened and that cilia mediate the expression of the Hh pathway target genes. Taken together, our data demonstrate that Hh signaling in Drosophila can be mediated by two pathways and that the ciliary Hh pathway is conserved from Drosophila to vertebrates.
  • Sabouri, Nasim, et al. (författare)
  • DNA replication through hard-to-replicate sites, including both highly transcribed RNA Pol II and Pol III genes, requires the S. pombe Pfh1 helicase
  • 2012
  • Ingår i: Genes & Development. - 0890-9369 .- 1549-5477. ; 26:6, s. 581-593
  • Tidskriftsartikel (refereegranskat)abstract
    • Replication forks encounter impediments as they move through the genome, including natural barriers due to stable protein complexes and highly transcribed genes. Unlike lesions generated by exogenous damage, natural barriers are encountered in every S phase. Like humans, Schizosaccharomyces pombe encodes a single Pif1 family DNA helicase, Pfh1. Here, we show that Pfh1 is required for efficient fork movement in the ribosomal DNA, the mating type locus, tRNA, 5S ribosomal RNA genes, and genes that are highly transcribed by RNA polymerase II. In addition, converged replication forks accumulated at all of these sites in the absence of Pfh1. The effects of Pfh1 on DNA replication are likely direct, as it had high binding to sites whose replication was impaired in its absence. Replication in the absence of Pfh1 resulted in DNA damage specifically at those sites that bound high levels of Pfh1 in wild-type cells and whose replication was slowed in its absence. Cells depleted of Pfh1 were inviable if they also lacked the human TIMELESS homolog Swi1, a replisome component that stabilizes stalled forks. Thus, Pfh1 promotes DNA replication and separation of converged replication forks and suppresses DNA damage at hard-to-replicate sites.
  • Habicher, Judith (författare)
  • Glycosaminoglycan Biosynthesis and Function in Zebrafish Development : Sugars Shaping Skeletons
  • 2015
  • Doktorsavhandling (övrigt vetenskapligt)abstract
    • Heparan sulfate (HS) and chondroitin/dermatan sulfate (CS/DS) proteoglycans are glycosylated proteins with important roles in animal development and homeostasis. HS and CS/DS are long, linear glycosaminoglycan (GAG) polysaccharides and attached to a core protein they form proteoglycans. GAGs on proteoglycans are often modified by sulfate groups and mainly found in the extracellular matrix or associated to the cell membrane. They interact with different proteins, for example signaling molecules, and influence developmental processes. Cells in cartilage produce a functionally specialized dense extracellular matrix, full of proteoglycans. Using the zebrafish as a model to study GAG biosynthesis we discovered that HS production is prioritized over CS/DS production, if the availability of link structures is restricted. We also found that the effects of removing HS and CS/DS biosynthetic enzymes in zebrafish larvae typically differ from what could be hypothesized solely from knowledge of the activity of each enzyme. These findings indicated a highly complex regulation of GAG biosynthesis and we thus proceeded to identify novel GAG biosynthetic enzymes in zebrafish and characterized their expression during early development. Notably, strong expression of CS/DS glycosyltransferases was found in cartilage structures, correlating with a drastic increase of CS/DS synthesis after two days of development, and high CS/DS deposition in cartilage. Finally, to understand how different GAG biosynthetic enzymes affect zebrafish development, we decided to use the CRISPR/Cas9 technology to generate new loss of function alleles for enzymes in HS and CS/DS biosynthesis. Some mutants show disturbed larval development or adult morphology, but we found many mutants to develop into adults without major morphological abnormalities, suggesting a high redundancy for GAG biosynthetic enzymes. Many GAG glycosyltransferases and modification enzymes have multiple isoforms, suggesting that a combination of mutations in one individual will become necessary to study the loss of specific modifications. To conclude, the zebrafish model gives new insights into the GAG machinery and the CRSIPR/Cas9 technology allows for swift production of new loss of function zebrafish lines with defective GAG biosynthesis.
  • Karlsson, Anna-Carin, et al. (författare)
  • The effect of a mutation in the thyroid stimulating hormone receptor (TSHR) on development, behaviour and TH levels in domesticated chickens
  • 2015
  • Ingår i: PLoS ONE. - : Public Library of Science. - 1932-6203 .- 1932-6203. ; 10:6
  • Tidskriftsartikel (refereegranskat)abstract
    • The thyroid stimulating hormone receptor (TSHR) has been suggested to be a “domestication locus” in the chicken, due to a strong selective sweep over the gene found in domesticated chickens, but not in their wild ancestor the Red Junglefowl (RJF). We investigated the effect of the mutation on development (incubation time), behaviour and thyroid hormone levels in intercross chickens homozygous for the mutation (d/d), wild type homozygotes (w/w) or heterozygotes (d/w). This allowed an assessment of the effect of genotype at this locus against a random mix of RJF and WL genotypes throughout the rest of the genome. The (d/d) genotype showed a longer incubation time, less fearful behaviours, lower number of aggressive behaviours and decreased levels of the thyroid hormone T4, in comparison to the (w/w) genotype. The difference between TSHR genotypes (d/d vs. w/w) in these respects mirrors the differences in development and behaviour between pure domesticated White Leghorns and pure RJF chickens. Our study indicates that the TSHR mutation affects typical domestication traits and may therefore have been important during the evolution of the domestic chicken.
Skapa referenser, mejla, bekava och länka
Typ av publikation
tidskriftsartikel (313)
doktorsavhandling (124)
annan publikation (43)
konferensbidrag (21)
forskningsöversikt (8)
bokkapitel (7)
visa fler...
licentiatavhandling (2)
recension (2)
bok (1)
visa färre...
Typ av innehåll
refereegranskat (336)
övrigt vetenskapligt (183)
populärvet., debatt m.m. (2)
Alvarez-Rodríguez, M ... (19)
Fundele, Reinald (18)
Eriksson, Per (13)
Alvarez, Mercedes (13)
de Paz, Paulino (13)
Anel, Luis (13)
visa fler...
Martinez-Pastor, Fel ... (12)
Fredriksson, Anders (11)
Pradhan, Ajay, 1983- (11)
Buratovic, Sonja (11)
Mannervik, Mattias (10)
Olsson, Per-Erik, 19 ... (10)
Viberg, Henrik (9)
Ohlsson, Rolf (9)
Betsholtz, Christer (8)
Stenerlöw, Bo (8)
Thor, Stefan (8)
Shi, Wei (8)
Rodriguez-Martinez, ... (7)
Gilthorpe, Jonathan (7)
Blom, Henning (6)
Ahlberg, Per E. (6)
Novak, Ondrej (6)
Jazin, Elena (6)
Borragan, Santiago (6)
Johansson, Frank (6)
Söderhäll, Irene (6)
Samakovlis, Christos ... (6)
Åström, Stefan U. (6)
Holmqvist, Per-Henri ... (6)
Brunström, Björn (5)
Ledin, Johan (5)
Jensen, Per (5)
Lumsden, Andrew (5)
Mattsson, Anna (5)
Boija, Ann (5)
Brandt, Ingvar (4)
Lundeberg, Joakim (4)
Ahlberg, Per Erik (4)
Schmid, Markus (4)
Allalou, Amin, 1981- (4)
Martinez-Serrano, Cr ... (4)
Andrae, Johanna (4)
Hauptmann, Giselbert (4)
Bahrampour, Shahrzad (4)
Roos, Anna, 1961- (4)
Thor, Stefan, Profes ... (4)
Barsoum, Emad, 1979- (4)
Chen, Jiang (4)
Jönsson, Maria, 1961 ... (4)
visa färre...
Uppsala universitet (261)
Umeå universitet (93)
Stockholms universitet (82)
Linköpings universitet (64)
Karolinska Institutet (19)
Örebro universitet (17)
visa fler...
Sveriges Lantbruksuniversitet (14)
Södertörns högskola (13)
Kungliga Tekniska Högskolan (12)
Lunds universitet (10)
Linnéuniversitetet (7)
Göteborgs universitet (3)
Naturhistoriska riksmuseet (3)
Högskolan Dalarna (2)
Högskolan Kristianstad (1)
Jönköping University (1)
Högskolan i Gävle (1)
visa färre...
Engelska (520)
Svenska (1)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (521)
Medicin och hälsovetenskap (54)
Humaniora (5)
Lantbruksvetenskap (4)
Samhällsvetenskap (4)


pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy