Reconstructing Genealogies

The genomes of living organisms record both genealogical and population histories. Our own genome tells a remarkable story of events in recent human evolution. Relatedness of individuals within and between populations and species can be determined by measuring the number of genetic differences between two individuals. When applied to segments of the genome that accumulate mutations at relatively constant rates over time, they can provide information about the time that has elapsed since the existence of their last common ancestor. Research shows that human and chimpanzee lineages diverged about six million years ago, that neanderthals and anatomically modern humans diverged 500 thousand years ago, and that all living humans can trace their ancestry to a maternal lineage that lived in Africa about 130 thousand years ago. Figure 2 illustrates differentiation of lineages and the effects of bottlenecks on diversity.

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