Adaptive Genetic Exchange: A Tangled History of Admixture and Evolutionary Innovation

Trends Ecol Evol. 2017 Aug;32(8):601-611. doi: 10.1016/j.tree.2017.05.007. Epub 2017 Jun 20.


Genetic exchange between divergent evolutionary lineages, from introgressive hybridization between locally adapted populations to insertion of retroviral sequences into eukaryotic genomes, has now been documented. The detection of frequent divergence-with-gene-flow contrasts the neo-Darwinian paradigm of largely allopatric diversification. Nevertheless, of even greater significance is the growing wealth of data suggesting that the recipients of the transferred genomic material gain adaptive phenotypes from the donor lineages. This adaptive enrichment is reflected by changes in pathogenicity in viruses and bacteria, the transformation of ecological amplitude in eukaryotes, and adaptive radiations in extremely diverse lineages. Although genetic exchange may produce maladaptive consequences, most of the recently reported examples suggest increases in fitness, and many such adaptive trait transfers have been identified in our own species.

Keywords: animals; horizontal gene transfer; introgressive hybridization; plants; prokaryotes; viral reassortment.

Publication types

  • Review

MeSH terms

  • Biological Evolution*
  • Eukaryota
  • Eukaryotic Cells
  • Gene Flow*
  • Hybridization, Genetic
  • Phylogeny