Molecular anthropology

Molecular anthropology is a field of anthropology in which molecular analysis is used to determine evolutionary links between ancient and modern human populations, as well as between contemporary species. Generally, comparisons are made between sequence, either DNA or protein sequence, however early studies used comparative serology.

By examining DNA sequences in different populations, scientists can determine the closeness of relationships between populations (or within populations). Certain similarities in genetic makeup let molecular anthropologists determine whether or not different groups of people belong to the same haplogroup, and thus if they share a common geographical origin. This is significant because it allows anthropologists to trace patterns of migration and settlement, which gives helpful insight as to how contemporary populations have formed and progressed over time.

Molecular anthropology has been extremely useful in establishing the evolutionary tree of humans and other primates, including closely related species like chimps and gorillas. While there are clearly many morphological similarities between humans and chimpanzees, for example, certain studies also have concluded that there is roughly a 98 percent commonality between the DNA of both species. However, more recent studies have modified the commonality of 98 percent to a commonality of 94 percent, showing that the genetic gap between humans and chimps is bigger than originally thought. Such information is useful in searching for common ancestors and coming to a better understanding of how humans evolved.

There are two continuous linkage groups in humans that are carried by a single sex. The first is the Y chromosome, which is passed from father to son. Anatomical females carry a Y chromosome only rarely, as a result of genetic defect. The other linkage group is the mitochondrial DNA (mtDNA). MtDNA can only be passed to the next generation by females but only under highly exceptional circumstances is mtDNA passed through males. The non-recombinant portion of the Y chromosome and the mtDNA, under normal circumstances, do not undergo productive recombination. Part of the Y chromosome can undergo recombination with the X chromosome and within ape history the boundary has changed. Such recombinant changes in the non-recombinant region of Y are extremely rare.

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