The Evolution of Horizontally Transferred Genes: a Model for Prokaryotes
Iñaki Comas and Fernando González-Candelas
from: Horizontal Gene Transfer in Microorganisms (Edited by: M. Pilar Francino). Caister Academic Press, U.K. (2012)
Horizontal gene transfer is a pervasive evolutionary process which has developed and is still developing an essential role in shaping biodiversity through providing opportunities for innovation, moving determinants of functions among taxa, opening opportunities for colonization of new niches, or acting as a catalyst for adaptation. However, its importance in evolution has only recently begun to be recognized. Reasons for this relatively late recognition of HGT and its relevance stem from two main sources. One is the availability, or rather the lack thereof, of appropriate information to infer the existence of HGT. This shortcoming has now been widely overcome with the large, and still growing at a very fast rate, number of completely sequenced genomes, which allow for precise phylogenetic reconstructions, along with the deployment of theoretical models necessary for inferring evolutionary events in deep-time. The second source is the appreciation that HGT does not leave an indelible stamp on the transferred genes because these continue evolving under a different genomic, and often ecological, environment which usually act synergistically to erase the initially clear marks that go along with those genes. In this chapter we provide an overview of these processes along with a model proposal that will help to better understand the consequences of the continuous evolution of laterally transferred genes at different evolutionary time-scales read more ...