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Höglund A, Henriksen R, Churcher AM, Guerrero-Bosagna CM, Martinez-Barrio A, Johnsson M, Jensen P, Wright D. The regulation of methylation on the Z chromosome and the identification of multiple novel Male Hyper-Methylated regions in the chicken. PLoS Genet 2024; 20:e1010719. [PMID: 38457441 PMCID: PMC10954189 DOI: 10.1371/journal.pgen.1010719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 03/20/2024] [Accepted: 01/31/2024] [Indexed: 03/10/2024] Open
Abstract
DNA methylation is a key regulator of eukaryote genomes, and is of particular relevance in the regulation of gene expression on the sex chromosomes, with a key role in dosage compensation in mammalian XY systems. In the case of birds, dosage compensation is largely absent, with it being restricted to two small Male Hyper-Methylated (MHM) regions on the Z chromosome. To investigate how variation in DNA methylation is regulated on the Z chromosome we utilised a wild x domestic advanced intercross in the chicken, with both hypothalamic methylomes and transcriptomes assayed in 124 individuals. The relatively large numbers of individuals allowed us to identify additional genomic MHM regions on the Z chromosome that were significantly differentially methylated between the sexes. These regions appear to down-regulate local gene expression in males, but not remove it entirely (unlike the lncRNAs identified in the initial MHM regions). These MHM regions were further tested and the most balanced genes appear to show decreased expression in males, whilst methylation appeared to be far more correlated with gene expression in the less balanced, as compared to the most balanced genes. In addition, quantitative trait loci (QTL) that regulate variation in methylation on the Z chromosome, and those loci that regulate methylation on the autosomes that derive from the Z chromosome were mapped. Trans-effect hotspots were also identified that were based on the autosomes but affected the Z, and also one that was based on the Z chromosome but that affected both autosomal and sex chromosome DNA methylation regulation. We show that both cis and trans loci that originate from the Z chromosome never exhibit an interaction with sex, whereas trans loci originating from the autosomes but affecting the Z chromosome always display such an interaction. Our results highlight how additional MHM regions are actually present on the Z chromosome, and they appear to have smaller-scale effects on gene expression in males. Quantitative variation in methylation is also regulated both from the autosomes to the Z chromosome, and from the Z chromosome to the autosomes.
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Affiliation(s)
- Andrey Höglund
- Science for Life Laboratory, Department of Environmental Science, Stockholm University, Stockholm, Sweden
| | - Rie Henriksen
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | | | - Carlos M. Guerrero-Bosagna
- Physiology and Environmental Toxicology Program, Department of Organismal Biology, Uppsala University, Uppsala, Sweden
| | | | - Martin Johnsson
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Per Jensen
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | - Dominic Wright
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
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Racicot KJ, Ham JR, Augustine JK, Henriksen R, Wright D, Iwaniuk AN. A Comparison of Telencephalon Composition among Chickens, Junglefowl, and Wild Galliforms. BRAIN, BEHAVIOR AND EVOLUTION 2024; 99:13-24. [PMID: 38368854 DOI: 10.1159/000537844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 02/08/2024] [Indexed: 02/20/2024]
Abstract
INTRODUCTION Domestication is the process of modifying animals for human benefit through selective breeding in captivity. One of the traits that often diverges is the size of the brain and its constituent regions; almost all domesticated species have relatively smaller brains and brain regions than their wild ancestors. Although the effects of domestication on the brain have been investigated across a range of both mammal and bird species, almost nothing is known about the neuroanatomical effects of domestication on the world's most common bird: the chicken (Gallus gallus). METHODS We compared the quantitative neuroanatomy of the telencephalon of white leghorn chickens with red junglefowl, their wild counterpart, and several wild galliform species. We focused specifically on the telencephalon because telencephalic regions typically exhibit the biggest differences in size in domesticate-wild comparisons. RESULTS Relative telencephalon size was larger in chickens than in junglefowl and ruffed grouse (Bonasa umbellus). The relative size of telencephalic regions did not differ between chickens and junglefowl, but did differ in comparison with ruffed grouse. Ruffed grouse had larger hyperpallia and smaller entopallial, nidopallial, and striatal volumes than chickens and junglefowl. Multivariate analyses that included an additional three wild grouse species corroborated these findings: chicken and junglefowl have relatively larger nidopallial and striatal volumes than grouse. Conversely, the mesopallial and hyperpallial volumes tended to be relatively smaller in chickens and junglefowl. CONCLUSION From this suite of comparisons, we conclude that chickens do not follow a pattern of widespread decreases in telencephalic region sizes that is often viewed as typical of domestication. Instead, chickens have undergone a mosaic of changes with some regions increasing and others decreasing in size, and there are few differences between chickens and junglefowl.
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Affiliation(s)
- Kelsey J Racicot
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Jackson R Ham
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Jacqueline K Augustine
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University at Lima, Lima, Ohio, USA
| | - Rie Henriksen
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, Linkoping, Sweden
| | - Dominic Wright
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, Linkoping, Sweden
| | - Andrew N Iwaniuk
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
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3
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Increased temperature during incubation increases the sociality of male broilers in later life. Appl Anim Behav Sci 2022. [DOI: 10.1016/j.applanim.2022.105815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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4
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Csillag A, Ádám Á, Zachar G. Avian models for brain mechanisms underlying altered social behavior in autism. Front Physiol 2022; 13:1032046. [PMID: 36388132 PMCID: PMC9650632 DOI: 10.3389/fphys.2022.1032046] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/17/2022] [Indexed: 08/23/2023] Open
Abstract
The current review is an update on experimental approaches in which birds serve as model species for the investigation of typical failure symptoms associated with autism spectrum disorder (ASD). The discussion is focused on deficiencies of social behavior, from social interactions of domestic chicks, based on visual and auditory cues, to vocal communication in songbirds. Two groups of pathogenetic/risk factors are discussed: 1) non-genetic (environmental/epigenetic) factors, exemplified by embryonic exposure to valproic acid (VPA), and 2) genetic factors, represented by a list of candidate genes and signaling pathways of diagnostic or predictive value in ASD patients. Given the similarities of birds as experimental models to humans (visual orientation, vocal learning, social cohesions), avian models usefully contribute toward the elucidation of the neural systems and developmental factors underlying ASD, improving the applicability of preclinical results obtained on laboratory rodents. Furthermore, they may predict potential susceptibility factors worthy of investigation (both by animal studies and by monitoring human babies at risk), with potential therapeutic consequence.
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Affiliation(s)
- András Csillag
- Department of Anatomy, Histology, and Embryology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
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5
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Bakovic V, Höglund A, Martin Cerezo ML, Henriksen R, Wright D. Genomic and gene expression associations to morphology of a sexual ornament in the chicken. G3 GENES|GENOMES|GENETICS 2022; 12:6633936. [PMID: 35801935 PMCID: PMC9434260 DOI: 10.1093/g3journal/jkac174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 06/27/2022] [Indexed: 11/12/2022]
Abstract
How sexual selection affects the genome ultimately relies on the strength and type of selection, and the genetic architecture of the involved traits. While associating genotype with phenotype often utilizes standard trait morphology, trait representations in morphospace using geometric morphometric approaches receive less focus in this regard. Here, we identify genetic associations to a sexual ornament, the comb, in the chicken system (Gallus gallus). Our approach combined genome-wide genotype and gene expression data (>30k genes) with different aspects of comb morphology in an advanced intercross line (F8) generated by crossing a wild-type Red Junglefowl with a domestic breed of chicken (White Leghorn). In total, 10 quantitative trait loci were found associated to various aspects of comb shape and size, while 1,184 expression QTL were found associated to gene expression patterns, among which 98 had overlapping confidence intervals with those of quantitative trait loci. Our results highlight both known genomic regions confirming previous records of a large effect quantitative trait loci associated to comb size, and novel quantitative trait loci associated to comb shape. Genes were considered candidates affecting comb morphology if they were found within both confidence intervals of the underlying quantitative trait loci and eQTL. Overlaps between quantitative trait loci and genome-wide selective sweeps identified in a previous study revealed that only loci associated to comb size may be experiencing on-going selection under domestication.
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Affiliation(s)
- Vid Bakovic
- IFM Biology, University of Linköping , Linköping 581 83, Sweden
| | - Andrey Höglund
- Science for Life Laboratory, Department of Environmental Science, Stockholm University , Stockholm 106 91, Sweden
| | | | - Rie Henriksen
- IFM Biology, University of Linköping , Linköping 581 83, Sweden
| | - Dominic Wright
- IFM Biology, University of Linköping , Linköping 581 83, Sweden
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6
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Carli G, Farabollini F. Environmental, ecological and methodological factors of Tonic Immobility (TI) modulation. PROGRESS IN BRAIN RESEARCH 2022; 271:101-132. [DOI: 10.1016/bs.pbr.2022.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Kohno S, Ogawa S, Shimmura T, Sato K, Tokutake Y. Myeloperoxidase expression in diencephalon is potentially associated with fear‐related behavior in chicks of laying hen. Anim Sci J 2022; 93:e13779. [PMID: 36345734 DOI: 10.1111/asj.13779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/03/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022]
Abstract
Preventing feather pecking (FP) in adult laying hens is important for the welfare of intensively poultry farming. Fear-related behavior in growing female layer chicks may predict FP in adult hens. In this study, in two representative laying breeds (White Leghorn [WL] and Rhode Island Red [RIR]) that have different FP frequencies, we identified a candidate gene associated with fear-related behavior in chicks and FP in adult hens. In the tonic immobility test and open-field test, the behavioral activity was lower in WL chicks than in RIR chicks (P < 0.01), suggesting that WL chicks were more fearful than RIR chicks. Based on previous studies, 51 genes that have been found to be differentially expressed in the brain between high- and low-FP populations were chosen, and their expression levels were screened in the chick diencephalon. This analysis revealed that myeloperoxidase (MPO) gene expression level was higher in WL chicks than that in RIR chicks (P < 0.05). Furthermore, STRING analysis predicted the gene network including MPO and MPO-related genes and revealed the association of these genes with fear-related behavior. These results suggest that MPO is potentially associated with fear-related behavior in growing female layer chicks and FP in adult hens.
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Affiliation(s)
- Suzuka Kohno
- Graduate School of Agricultural Science Tohoku University Sendai Miyagi Japan
| | - Shinichiro Ogawa
- Graduate School of Agricultural Science Tohoku University Sendai Miyagi Japan
- Division of Meat Animal and Poultry Research Institute of Livestock and Grassland Science, NARO Tsukuba Ibaraki Japan
| | - Tsuyoshi Shimmura
- Department of Biological Production Tokyo University of Agriculture and Technology Tokyo Japan
| | - Kan Sato
- Graduate School of Agricultural Science Tohoku University Sendai Miyagi Japan
| | - Yukako Tokutake
- Graduate School of Agricultural Science Tohoku University Sendai Miyagi Japan
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8
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Höglund A, Henriksen R, Fogelholm J, Churcher AM, Guerrero-Bosagna CM, Martinez-Barrio A, Johnsson M, Jensen P, Wright D. The methylation landscape and its role in domestication and gene regulation in the chicken. Nat Ecol Evol 2020; 4:1713-1724. [PMID: 32958860 DOI: 10.1038/s41559-020-01310-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 08/26/2020] [Indexed: 01/06/2023]
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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Affiliation(s)
- Andrey Höglund
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | - Rie Henriksen
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | - Jesper Fogelholm
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | | | - Carlos M Guerrero-Bosagna
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden.,Evolutionary Biology Centrum, Dept of Organismal Biology, Uppsala University, Uppsala, Sweden
| | | | - Martin Johnsson
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Edinburgh, UK.,Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Per Jensen
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | - Dominic Wright
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden.
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9
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Henriksen R, Höglund A, Fogelholm J, Abbey-Lee R, Johnsson M, Dingemanse NJ, Wright D. Intra-Individual Behavioural Variability: A Trait under Genetic Control. Int J Mol Sci 2020; 21:ijms21218069. [PMID: 33138119 PMCID: PMC7663371 DOI: 10.3390/ijms21218069] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 10/15/2020] [Accepted: 10/19/2020] [Indexed: 11/30/2022] Open
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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Affiliation(s)
- Rie Henriksen
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden; (A.H.); (R.A.-L.); (M.J.)
- Correspondence: (R.H.); (D.W.)
| | - Andrey Höglund
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden; (A.H.); (R.A.-L.); (M.J.)
| | - Jesper Fogelholm
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden; (A.H.); (R.A.-L.); (M.J.)
| | - Robin Abbey-Lee
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden; (A.H.); (R.A.-L.); (M.J.)
| | - Martin Johnsson
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden; (A.H.); (R.A.-L.); (M.J.)
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Edinburgh EH25 9RG, UK
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
| | - Niels J. Dingemanse
- Ludwig Maximilians University of Munich (LMU), 82152 Munich, Planegg-Martinsried, Germany;
| | - Dominic Wright
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden; (A.H.); (R.A.-L.); (M.J.)
- Correspondence: (R.H.); (D.W.)
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10
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Katajamaa R, Jensen P. Tameness correlates with domestication related traits in a Red Junglefowl intercross. GENES BRAIN AND BEHAVIOR 2020; 20:e12704. [PMID: 32969588 PMCID: PMC7988571 DOI: 10.1111/gbb.12704] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 09/15/2020] [Accepted: 09/20/2020] [Indexed: 01/21/2023]
Abstract
Early animal domestication may have been driven by selection on tameness. Selection on only tameness can bring about correlated selection responses in other traits, not intentionally selected upon, which may be one cause of the domesticated phenotype. We predicted that genetically reduced fear towards humans in Red Junglefowl, ancestors of domesticated chickens, would be correlated to other traits included in the domesticated phenotype. Fear level was determined by a standardised behaviour test, where the reaction towards an approaching human was recorded. We first selected birds for eight generations for either high or low fear levels in this test, to create two divergent selection lines. An F3 intercross, with birds from the eighth generation as parentals, was generated to study correlations between fear‐of‐human scores and other unselected phenotypes, possibly caused by pleiotropy or linkage. Low fear‐of‐human scores were associated with higher body weight and growth rates, and with increased activity in an open field test, indicating less general fearfulness. In females, low fear‐of‐human scores were also associated with more efficient fear habituation and in males with an increased tendency to emit food calls in a mirror test, indicating increased social dominance. Low fear‐of‐human scores were also associated with smaller brain relative to body weight, and with larger cerebrum relative to total brain weight in females. All these effects are in line with the changes observed in domesticated chickens compared to their ancestors, and we conclude that tameness may have been a driving factor underlying some aspects of the domesticated phenotype.
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Affiliation(s)
| | - Per Jensen
- IFM Biology, Linköping University, Linköping, Sweden
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11
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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. BMC Genomics 2020; 21:518. [PMID: 32727510 PMCID: PMC7392834 DOI: 10.1186/s12864-020-06908-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 07/13/2020] [Indexed: 12/03/2022] Open
Abstract
Background Large 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). Results We 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). Conclusion The 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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12
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Fogelholm J, Inkabi S, Höglund A, Abbey-Lee R, Johnsson M, Jensen P, Henriksen R, Wright D. Genetical Genomics of Tonic Immobility in the Chicken. Genes (Basel) 2019; 10:genes10050341. [PMID: 31067744 PMCID: PMC6562468 DOI: 10.3390/genes10050341] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/17/2019] [Accepted: 04/30/2019] [Indexed: 11/17/2022] Open
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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Affiliation(s)
- Jesper Fogelholm
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden.
| | - Samuel Inkabi
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden.
| | - Andrey Höglund
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden.
| | - Robin Abbey-Lee
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden.
| | - Martin Johnsson
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian, Scotland EH25 9RG, UK.
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7023, 750 07 Uppsala, Sweden.
| | - Per Jensen
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden.
| | - Rie Henriksen
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden.
| | - Dominic Wright
- AVIAN Behavioural Genomics and Physiology Group, IFM Biology, Linköping University, 58183 Linköping, Sweden.
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