02 Gene Mapping

Genetic Recombination

  • The law of segregation describes the phenomenon in which gametogenesis results in the separation of paired chromosomes so that the offspring inherit only half of each parent's genetic composition.

  • 50% chance gametes will have parental version of genes
  • 50% chance of either having FM or fm

  • 50% chance for recombinant

  • use frequency of recombination of genes to determine how far each gene is away from each other
  • recombination of AB 16%
  • AB farther apart, higher frequency of recombination
  • AC closer, smaller frequency

Linkage Disequilibrium

  • even with large family, may never see recombination event

  • expected frequency of mixture of allele
  • if expected similar to reality = linkage equilibrium
  • not similar to Hardy Weinberg law (same gene, different alleles)

  • closer together = greater linkage disequilibrium
  • use linkage disequilibrium to study genes close together that can't study with family

  • at first, disequilibrium highest because closest together
  • with later generations, farther apart, more in equilibrium