Conditional ancestral times and related properties of an extant mutant at a locus A given the number of segregating sites observed at a linked locus B

J Math Biol. 2002 May;44(5):427-49. doi: 10.1007/s002850100137.

Abstract

It is shown how the mean ancestral times at one locus are affected in a two- locus model with recombination when information is given regarding the number of segregating sites at another locus. For samples of n genes, recursive equations are derived that describe precisely the evolution of the time-depth of such a linked genealogy. Exact numerical solutions and Markov chain Monte Carlo simulations are discussed and compared. The dependence of some properties of a singleton mutation on waiting times between events in the two-locus genealogy is quantified and illustrates the effect of recombination on these properties. The following cases are presented: (1) the distribution of the number of mutant genes in a sample arising from a singleton mutation; (2) the probability that an allele observed in a genes of a sample of size n is the ancestral type (the oldest); (3) the expectation and variance of the age of a mutant having b copies in a sample of n genes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • DNA / genetics*
  • Evolution, Molecular
  • Genetic Linkage*
  • Humans
  • Markov Chains
  • Models, Genetic*
  • Monte Carlo Method
  • Mutation*
  • Numerical Analysis, Computer-Assisted
  • Recombination, Genetic

Substances

  • DNA