Evolution of repeated DNA sequences by unequal crossover

Science. 1976 Feb 13;191(4227):528-35. doi: 10.1126/science.1251186.

Abstract

It is often supposed that highly repetitious DNA's arise only as a result of unusual mechanisms or in response to selective pressure. My arguments and simulations suggest, by contrast, that a pattern of tandem repeats is the natural state of DNA whose sequence is not maintained by selection. The simulations show that periodicities can develop readily from nonreptitious DNA as a result of the random accumulation of random mutations and random homology-dependent unequal crossovers. The lengths of these periodicities, and the patterns of subrepeats within them, would fluctuate in evolution, with the probability of a given pattern being dependent on the unknown exact nature of the crossover mechanism. Qualitatively, then, unequal crossover provides a reasonable and uncontrived explanation for the prevalence of highly repeated sequences in DNA and for the patterns of periodicity they evince.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Biological Evolution*
  • Chromatids
  • Computers
  • Crossing Over, Genetic*
  • DNA*
  • DNA, Satellite*
  • Genes
  • Models, Biological
  • Mutation
  • RNA, Ribosomal

Substances

  • DNA, Satellite
  • RNA, Ribosomal
  • DNA