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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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DNA sequences evolve under many locus-specific pressures that modify protein functions, expression levels, and gene regulation. We show that DNA sequences also adapt globally under an evolutionary force that tunes the frequency of short DNA motifs. We argue that DNA binding processes that are present in all domains of life give rise to distinct global pressures in different genomes. This global selection has a universal hallmark that we detect in all sequenced genomes, with selective coefficients that are on average only slightly higher than point mutation rates. We show that global selection operates through tiny selective steps over evolutionary timescales spanning millions of years, and is responsible for an ancient phylogenetic signal in DNA sequences. Importantly, this process can efficiently increase fitness only when recombination is present. We conclude that global selection provides a ubiquitous selective advantage for recombination and sex.
