Polar bear evolution is marked by rapid changes in gene copy number in response to dietary shift

2019/06/17 by David C. Rinker, Natalya Katerina Specian, Shu Zhao +1 · 1 voice · 5 citations
Environmental Science · Biochemistry, Genetics and Molecular Biology · #Marine animal studies overview #Genomics and Phylogenetic Studies #Environmental DNA in Biodiversity Studies

paper · pdf · doi:10.1073/pnas.1901093116

Abstract

Significance Copy number variation describes the degree to which contiguous genomic regions differ in their number of copies among individuals. Copy number variable regions can drive ecological adaptation, particularly when they contain genes. Here, we compare differences in gene copy numbers among 17 polar bear and 9 brown bear individuals to evaluate the impact of copy number variation on polar bear evolution. Polar bears and brown bears are ideal species for such an analysis as they are closely related, yet ecologically distinct. Our analysis identified variation in copy number for genes linked to dietary and ecological requirements of the bear species. These results suggest that genic copy number variation has played an important role in polar bear adaptation to the Arctic.

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Discussions

• Polar bears and brown bears are close relatives but have very different diets! Polar bears (which eat mostly seals) have fewer copies of the gene AMY1B (important in starch digestion!) relative to bro [bsky, 25 points, 1 comments]

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