Landscape and evolution of cis- and trans-regulation in chicken genome between two contrasted breeds analyzed in three tissues at one day of age

Abstract

Background Gene expression variation is an important mechanism underlying phenotypic variation, and can occur via cis- and trans-regulation. In order to understand the role of cis- and trans-regulatory variation on population divergence of chicken, we developed reciprocal crosses of two chicken breeds, White Leghorn and Cornish Game, with major differences in size and reproductive traits, and used them to identify the degree of cis versus trans variation in brain, liver and muscle of both male and female samples at 1-day age. Results We provided a landscape about how the transcriptomes are regulated between two contrasted breeds by allele specific expression analysis. Our results showed that compared with the cis-regulated genes, trans-acted genes existed more extensively in the chicken genome. Furthermore, a widespread compensatory tendency exists in chicken genome. Most importantly, we found the evidence of stronger purifying selection for trans-regulatory variation than the cis-elements. Conclusions Our research performed the first study to describe the transcriptome regulation between White Leghorn and Cornish Game breeds and suggests that artificial selection associated with domestication in chicken may have more often acted on trans-regulatory variation.