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New preprint up on the effects of GC-biased gene conversion on patterns of genetic diversity in general and butterfly genomes in particular. (1/8) https://www.biorxiv.org/content/10.1101/2020.11.10.376566v1
As some of you may know, mismatches in conversion tracts during recombination are preferentially biased in repair towards G and C alleles in many species. (2/8) Great review by @GaltierNicolas and @duret_lbbe: https://www.annualreviews.org/doi/10.1146/annurev-genom-082908-150001?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed
Actually, this GC-biased gene conversion (gBGC) will mimic the signature of selection on A/T -> G/C SNPs. The strength of this force scales with e.g. effective population size and recombination rate among others. (3/8)
But mutation is generally several times more common in the reverse direction G/C -> A/T. How does mutation bias and gBGC interact to shape genetic diversity? (4/8)
We repurposed a model on codon usage bias and observed that gBGC may increase genetic diversity over time if balanced by a mutation bias (>1) at GC content in the range ~0.2-0.6. (5/8)
Why is this important? Well many researchers have observed that recombination rate and diversity are positively correlated-> pointing towards widespread impact of selection. (6/8)
We show that neutral forces may also cause this correlation through a positive correlation between recombination and GC - expected under gBGC. (7/8)
Goodbye selection? Not exactly, we reject gBGC as main determinant of diversity in wood white butterflies and see indications that both linked selection and GC content itself may affect diversity. Thanks for reading! (8/8)
Big thanks to Carina Farah Mugal and @niclasbackstrom for many hours of discussion and supervision! (9/8)
