Genetic Drift (MFE)

• Genetic Drift

  • a change of allele freq. in a pop. due to chance processes
  • usually results in a loss of genetic variation over generations
  • occurs in all pops. but has a larger effect on smaller pops. as the chance of fixation or extinction of alleles are higher
• Founder Effect

  • occurs when a new colony is started by a few members of the original pop.
  • small pop. that branches off may not be genetically representative as only a fraction of the total genetic diversity of the original pop. is represented
  • isolated pop. has less genetic diversity and deterious alleles may have a higher chance of coming together
• Bottleneck Effect

  • a catastrophic event that reduces the pop. significantly
  • earthquakes, floods, disease
  • the remaining pop. rarely represents the actual makeup of the initial pop.
  • leaves less variation among surviving indvs.