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Biased Gene Conversion and Its Impact on Genome Evolution

  1. Claude Bhérer1,
  2. Adam Auton2

Published Online: 16 JUN 2014

DOI: 10.1002/9780470015902.a0020834.pub2

eLS

eLS

How to Cite

Bhérer, C. and Auton, A. 2014. Biased Gene Conversion and Its Impact on Genome Evolution. eLS. .

Author Information

  1. 1

    Université de Montréal, Montréal, Québec, Canada

  2. 2

    Albert Einstein College of Medicine, Bronx, New York, USA

Publication History

  1. Published Online: 16 JUN 2014

Abstract

In most eukaryotes, genetic information is exchanged between homologous chromosomes via the process of recombination. As part of this process, short deoxyribonucleic acid (DNA) tracts of less than 1 kb in length are exchanged between chromosomes in an asymmetric fashion in a process known as gene conversion. When such gene conversion events occur within the vicinity of heterozygous loci, this asymmetric exchange of DNA can result in the non-Mendelian transmission of alleles. Multiple lines of evidence suggest that this non-Mendelian transmission is biased in favour of G and C alleles at the expense of A and T alleles. This process, known as biased gene conversion, has a number of important implications for understanding the behaviour of alleles within a population and the base composition of the genome itself.

Key Concepts:

  • Biased gene conversion is the preferential transmission of certain alleles to the next generation, arising from asymmetries in the gene conversion process.

  • Biased gene conversion appears to preferentially favour GC alleles over AT alleles, resulting in the overtransmission of GC alleles in regions of high recombination.

  • Biased gene conversion can increase the frequency of an allele in a population.

  • Consistent biased gene conversion can ultimately influence the base composition of the genome, leading to increased levels of GC content.

  • Although a difficult phenomenon to measure, multiple lines of experimental and evolutionary evidence support the existence of biased gene conversion.

Keywords:

  • recombination;
  • biased gene conversion;
  • GC content;
  • evolution;
  • substitution rate