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bioRxiv · 10.1101/800185

Large X-linked palindromes undergo arm-to-arm gene conversion across Mus lineages

Swanepoel, C. M.·Gerlinger, E. R.·Mueller, J. L.
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Abstract

Large (>10kb), nearly-identical (>99% nucleotide identity), palindromic sequences are enriched on mammalian sex chromosomes. Primate Y-palindromes undergo high rates of arm-to-arm gene conversion, a proposed mechanism for maintaining their sequence integrity in the absence of X-Y recombination. It is unclear whether X-palindromes, which can freely recombine in females, undergo arm-to-arm gene conversion and, if so, at what rate. We generated high-quality sequence assemblies of Mus molossinus and Mus spretus X-palindromic regions and compared them to orthologous Mus musculus X-palindromes. Our evolutionary sequence comparisons found evidence of X-palindrome arm-to-arm gene conversion at rates comparable to rates of autosomal allelic gene conversion in mice. Mus X-palindrome genes also exhibit higher than expected sequence diversification, indicating gene conversion may facilitate the rapid evolution of palindrome-associated genes. We conclude that in addition to maintaining genes sequence integrity via sequence homogenization, arm-to-arm gene conversion can also rapidly drive genetic evolution via sequence diversification.

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Swanepoel, C. M., Gerlinger, E. R., Mueller, J. L.. 2019-10-10. Large X-linked palindromes undergo arm-to-arm gene conversion across Mus lineages. https://doi.org/10.1101/800185

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