Brain gene expression in relation to fearfulness in female red junglefowl (<i>Gallus gallus</i>)

Jöngren, Markus; Westander, Jennie; Nätt, Daniel; Jensen, Per

doi:10.1111/j.1601-183x.2010.00612.x

Cited by 21 publications

(22 citation statements)

References 39 publications

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“…It controls the timing and intensity of gene expression and therefore is crucial to understanding phenotypic differences between populations. As behavioural variation often correlates with variation in gene expression (Hofmann, 2003;Jöngren et al, 2010), epigenetic mechanisms should be important in behaviour regulation as well. However, the research area is still novel, and relatively unexplored.…”

Section: Epigenetic Mechanisms: What Causes Differences In Gene Exprementioning

confidence: 99%

Adding ‘epi-’ to behaviour genetics: implications for animal domestication

Jensen

2015

Journal of Experimental Biology

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In this review, it is argued that greatly improved understanding of domestication may be gained from extending the field of behaviour genetics to also include epigenetics. Domestication offers an interesting framework of rapid evolutionary changes caused by welldefined selection pressures. Behaviour is an important phenotype in this context, as it represents the primary means of response to environmental challenges. An overview is provided of the evidence for genetic involvement in behavioural control and the presently used methods for finding so-called behaviour genes. This shows that evolutionary changes in behaviour are to a large extent correlated to changes in patterns of gene expression, which brings epigenetics into the focus. This area is concerned with the mechanisms controlling the timing and extent of gene expression, and a lot of focus has been placed on methylation of cytosine in promoter regions, usually associated with genetic downregulation. The review considers the available evidence that environmental input, for example stress, can modify methylation and other epigenetic marks and subsequently affect behaviour. Furthermore, several studies are reviewed, demonstrating that acquired epigenetic modifications can be inherited and cause trans-generational behaviour changes. In conclusion, epigenetics may signify a new paradigm in this respect, as it shows that genomic modifications can be caused by environmental signals, and random mutations in DNA sequence are therefore not the only sources of heritable genetic variation.

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Section: Epigenetic Mechanisms: What Causes Differences In Gene Exprementioning

confidence: 99%

Adding ‘epi-’ to behaviour genetics: implications for animal domestication

Jensen

2015

Journal of Experimental Biology

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“…The fear tests used in this study are frequently used in chicken research and are considered to assess fear (Campler et al 2009;Jensen 2005, 2008;Jöngren et al 2010). In an earlier study, Jöngren et al (2010) exposed Red Junglefowl females to similar fear tests and found two major components explaining 48.4% of the variance in a PCA.…”

Section: The Domestic Phenotypementioning

confidence: 85%

“…In an earlier study, Jöngren et al (2010) exposed Red Junglefowl females to similar fear tests and found two major components explaining 48.4% of the variance in a PCA. The first component was interpreted as a general fear factor whereas the second was mainly explained by TI.…”

Section: The Domestic Phenotypementioning

confidence: 92%

Early domestication? : Phenotypic alterations of Red Junglefowl selected for divergent fear of humans

Agnvall¹

2016

Linköping Studies in Science and Technology. Dissertations

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Till min Pärla och min Skatt, tack för att ni gör mitt liv så mycket mer, av allt. Älskar er till månen och tillbaka Foto Kenneth DanielssonAbstract Domestication is the process through which animals adapt to conditions provided by humans. The domesticated phenotype differs from wild ancestors in a number of traits relating to physiology, morphology and behaviour. One of the most striking differences is the animals' fear response towards humans, and reduced fear of humans is assumed to have been an early prerequisite for the success of domestication. The early alterations seen in the domesticated phenotype may be traits developed as a correlated selection response due to tameness rather than selected upon one by one.This thesis summarizes a project where Red Junglefowl were selected for divergent fear of humans during six generations. In every generation, fear response to human was assessed in a standardized test and, according to fear score, the animals were bred for either high fear of humans (H) or low fear of humans (L). The animals were, above that of the standardized selection test, behaviourally phenotyped in different tests in each generation mainly focusing on fear, exploration and social behaviour. In addition to behaviour, the animals were phenotyped for body weight, egg weight, metabolism, feed intake, plumage condition, blood plasma corticosterone and peripheral serotonin. After culling, vital organs and brains were harvested and weighed.In paper I, we demonstrated that the selection trait has a significant genetic heritability and is genetically correlated with other behavioural responses associated with fearfulness and exploration. In paper II, we concluded that animals from the L strain had better plumage condition, higher weight, laid larger eggs and also generated larger offspring. Furthermore, when tested in a social dominance test with a limited resource, they received less and performed more aggression regardless of whether the restricted source was edible or not. In paper III, we revealed that animals from the L strain had higher basal metabolic rate as chicks, gained more weight in relation to feed intake and were bolder in a Novel Object test. Furthermore, the L males had higher plasma levels of peripheral serotonin, but the corticosterone after a restraint stress test did not differ. In paper IV and V, we concluded the project by comparing brain and organ weights as well as behaviour of the parental generation (P0) with the fifth selected generation (S5). The absolute brain weight as well as the weight specific brain weight were larger in the animals selected on H than in the L-animals. The relative weight of telencephalon was significantly higher in H whereas relative weight of cerebellum was significantly lower. Heart, liver, spleen and testes were all relatively heavier in H animals than in L. Interestingly, the behaviours assessed in P0 and S5 seemed to be rather resilient to the selection with only small differences in S5.To summarize, the selection on divergent tameness in Red Jung...

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“…Egg layers show altered and less extreme antipredatory behavior, and fear related behaviors in the chicken have been reduced, maybe as the co-existence with humans has relaxed the natural selection pressure of predation [71,72]. Transmission of behavioral differences over generations has been shown to have underlying genetic components [73,74], as do differences in fear within populations [75].…”

Section: From Wild To Domestic Chickenmentioning

confidence: 99%

Chicken domestication : Effects of tameness on brain gene expression and DNA methylation

Bélteky¹

2016

Linköping Studies in Science and Technology. Dissertations

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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. Populärvetenskaplig sammanfattningDomesticering, när en population djur anpassas till ett liv i fångenskap och nära kontakt med människor, är en process som under kort tid ger upphov till stora förändringar hos djuret under selektion, såsom skillnader i beteende, fysiologi, storlek, reproduktion och fä...

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Brain gene expression in relation to fearfulness in female red junglefowl (Gallus gallus)

Cited by 21 publications

References 39 publications

Adding ‘epi-’ to behaviour genetics: implications for animal domestication

Adding ‘epi-’ to behaviour genetics: implications for animal domestication

Early domestication? : Phenotypic alterations of Red Junglefowl selected for divergent fear of humans

Chicken domestication : Effects of tameness on brain gene expression and DNA methylation

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