非表示:
キーワード:
-
要旨:
Duplicate genes emerge as copy-number variations (CNVs) at the population level, and remain copy-number polymorphic
until they are fixed or lost. The successful establishment of such structural polymorphisms in the genome plays an
important role in evolution by promoting genetic diversity, complexity and innovation. To characterize the early
evolutionary stages of duplicate genes and their potential adaptive benefits, we combine comparative genomics with
population genomics analyses to evaluate the distribution and impact of CNVs across natural populations of an ecogenomic
model, the three-spined stickleback. With whole genome sequences of 66 individuals from populations inhabiting
three distinct habitats, we find that CNVs generally occur at low frequencies and are often only found in one of the 11
populations surveyed. A subset of CNVs, however, displays copy-number differentiation between populations, showing
elevated within-population frequencies consistent with local adaptation. By comparing teleost genomes to identify lineagespecific
genes and duplications in sticklebacks, we highlight rampant gene content differences among individuals in which
over 30% of young duplicate genes are CNVs. These CNV genes are evolving rapidly at the molecular level and are enriched
with functional categories associated with environmental interactions, depicting the dynamic early copy-number
polymorphic stage of genes during population differentiation.
