A Genetic Christmas Story

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Jim Feaser, an oil economist from Houston, TX, recently caught the DNA ancestry bug. He found a not-so-distant relative living across town -- after recruiting 15 other people with his last name to get DNA tests.

Last year, Feaster and his wife went to a family reunion of their newly found relations. “We acted like we were cousins," says Feaster, who first became interested in deep ancestry testing after watching a PBS special on Spencer Wells, the population geneticist who's leading the Genographic Project. According to the test, the two Feasters share a common ancestor within the last few hundred years. They're now trying to track down that common ancestor to verify the DNA link.

How DNA Home Testing Works
For men only: Paternal Line analysis compares DNA markers on a part of the Y chromosome that is passed stably from fathers to sons. It can be used only by males (since only men have a Y chromosome). One subset of the DNA markers can be used to indicate the haplogroup to which an individual belongs; another subset, to determine if two men are related.

For women and men: Maternal Line analysis compares DNA from the mitochondria, a component of the cell passed from mothers to children. Both men and women can use this type of test to study their maternal ancestry. The mitochondrial DNA used in these tests changes very slowly, so it's more useful for studying distant relatedness, rather than recent family connections.

For whole populations: Autosomal analysis uses DNA from chromosomes other than the X and Y sex-linked ones. Scientists look for different markers that are associated with specific populations, such as Africans, Europeans, Asians, or Native Americans. These markers can also be used to determine the relatedness of two individuals and to create genetic family trees.