Summary: Part 2

Natural selection leaves behind a genetic signature.

  • Alleles that are under positive selection quickly increase in frequency in a population, taking along neighboring alleles.
  • This results in long stretches of the same combinations of alleles in a population.
A diagram titled Evidence of Selection showing change in allele frequencies of five individuals over generations. In the first set of alleles, labeled Adaptive mutation arises, one individual is red and the other four are blue. In the second set of alleles, labeled Positive selection, 4 individuals are red and one is blue. After many more generations, the third set of alleles, labeled Recombination over time, also has 4 red and one blue individual.