ANT 1 Lecture Notes - Lecture 19: Spina Bifida, Human Body, Hemoglobin
Document Summary
Molecular data imply that all modern human populations outside of africa are descendants of people that moved out of africa about 60 kya. When populations expand, local groups become isolated from each other and genetic differences begin to accumulate. Populations furthest away from the original source contain the least variation. This is why genetic variation within a population is negatively correlated with geographic distance from africa. In other words, the farther the population is from africa, the less genetic variation within that population. Mitochondrial dna tells a similar story: we can use the global variation in mtdna to reconstruct a phylogeny. Shows that the deepest branches in the phylogenetic tree are in africa. One african branch links africans with the rest of the world. Gradual variation over geographic distances called clinal variation or clines . Those groups who live closest to each other are more similar than those who live farther away.
