DETECTION AND QUANTIFICATION OF CONCERTED EVOLUTION AND MOLECULAR DRIVE

Concerted evolution is a distribution pattern of mutations in multiple copy sequences such that there is a greater similarity in sequence among the members of a repeated family from within a species than there is among the members of the family drawn from different species. There are several genomic mechanisms responsible for such patterns, which are involved, in their different ways, with the nonreciprocal transfer of information between members of a family. Prominent among these turnover mechanisms are unequal crossing-over and gene conversion, but other mechanisms such as DNA transposition, RNA-mediated sequence transfers, and DNA slippage are also involved. The continual, stochastic, or biased gain and loss of sequence variants within individuals can ultimately lead to the concomitant spread (molecular drive) of a variant through a family (homogenization) and through a sexual population (fixation). Molecular drive is a process, consequential on the mechanisms of DNA turnover that can explain observed patterns of concerted evolution. It can bring about, like natural selection and genetic drift, a long-term change in the genetic composition of a population with respect to a given family of sequences. © 1993