An AT mutational bias in the tiny GC-rich endosymbiont genome of Hodgkinia.

ABSTRACT: The fractional guanine + cytosine (GC) contents of sequenced bacterial genomes range from 13% to 75%. Despite several decades of research aimed at understanding this wide variation, the forces controlling GC content are not well understood. Recent work has suggested that a universal adenine + thymine (AT) mutational bias exists in all bacteria and that the elevated GC contents found in some bacterial genomes is due to genome-wide selection for increased GC content. These results are generally consistent with the low GC contents observed in most strict endosymbiotic bacterial genomes, where the loss of DNA repair mechanisms combined with the population genetic effects of small effective population sizes and decreased recombination should lower the efficacy of selection and shift the equilib

SUBMITTER: Van Leuven JT 

PROVIDER: S-EPMC3267392 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature