Abstracts (first author)
Selection on epigenetic variation may have been important in domestication of chickens
Author(s): Jensen P, Nätt D, Jonsson M, Beltéky J, Wright D
Epigenetic variation may cause broad phenotypic effects in animals. However, it has been debated to what extent expression variation and epigenetic modifications, such as patterns of DNA methylation, are transferred across generations, and therefore it is uncertain what role epigenetic variation may play in evolutionary processes. We compared gene expression and methylation profiles in thalamus/hypothalamus in Red Junglefowl, the ancestor of domestic chickens, and a domesticated egg laying breed (White Leghorn, WL). There were significant differeces in gene expression as well as methylation, which were largely maintained in the offspring, demonstrating reliable inheritance of epigenetic variation. More than 70% of the differentially methylated loci were hypermethylated in WL, indicating that methylations have accumulated during domestication. Furthermore, there was an over-representation of differentially expressed and methylated genes in selective sweep regions, previously shown to be associated with chicken domestication. The results show that epigenetic variation is inherited in chickens, and we suggest that selection of favourable epigenomes, may have been an important aspect of chicken domestication. This could have happened either by selection of genotypes affecting epigenetic states, or by selection of methylation states which are inherited independently of sequence differences. The relationship between specific epigenetic variants and phenotype remains to be investigated.