ANTHRBIO 201 1st Edition Lecture 6A. sex isn’t the only drive for reproduction; forces of evolutionary change1. natural selection2. mutation3. migration4. genetic drifII. MutationA. ultimate source of genetic variabilityB. point mutation1. single base pair change for the proteinsC. Physical basis of mutations: chromosomal deletions1. 12345 → 12452. insertions, deletions, rearrangingD. Mutation rates1. measured in events per base pairs per generations (u)2. human u: 1/100 mil. base pairs per generation3. human genome: 3 million base pairs4. enough variation to ensure evolutionary process can proceedThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.E. Evolutionary effect of mutations1. cause slow steady loss of existing alleles2. change gene frequencies over time, at a slow rate3. A (u) → a4. delta p= change in frequency of allele A, p=frequency of allele A5. minimal impact on changing gene frequenciesIII. MigrationA. gene flow: the movement of genes from one population to anotherB. Predicated on:1. dispersal of individuals2. ability of individuals of the same species to mateC. Significance1. migration homogenizes and maintains similarities across populationsD. Evolutionary Effect1. can be really large- only takes one2. can produce large changes in gene frequencies over time3. under certain circumstances it only takes a single migrant to besubstantialE. African Americans1. west african contribution to individual african-american ancestry is onaverage about 80%IV. Genetic DrifA. changes in gene frequencies that occur through sampling error in finitepopulationsB. occurs due to the random effects of sampling variation in small populationsC. occurs during genetic transmissions in small populationsD. changes frequency of genes from one generation to the nextE. Factors affecting1. drif causes larger variations in small populations than in larger ones2. example: poll US congress approval ratinga) survey- 10 people, 50% approveb) survey 10,000 people 85% disapproveF. drif causes isolated populations to become genetically different from eachotherG. drif leads to unpredictable changes in gene