Predominance of < i > cis < /i > -regulatory changes in parallel expression divergence of sticklebacks

Regulation of gene expression is thought to play a major role in adaptation but the relative importance ofcis- andtrans- regulatory mechanisms in the early stages of adaptive divergence is unclear. Using RNAseq of threespine stickleback fish gill tissue from four independent marine-freshwater ecotype pairs and their F1 hybrids, we show thatcis-acting (allele-specific) regulation consistently predominates gene expression divergence. Genes showing parallel marine-freshwater expression divergence are found near to adaptive genomic regions, show signatures of natural selection around their transcription start sites and are enriched forcis-regulatory control. For genes with parallel increased expression among freshwater fish, the quantitative degree ofcis- andtrans-regulation is also highly correlated across populations, suggesting a shared genetic basis. Compared to other forms of regulation,cis-regulation tends to show greater additivity and stability across different genetic and environmental contexts, making it a fertile substrate for the early stages of adaptive evolution.
Source: eLife - Category: Biomedical Science Tags: Evolutionary Biology Genetics and Genomics Source Type: research