Autosomal Testing (atDNA)

Both men and women can do this test. Since we inherit atDNA (some companies use auDNA) from all of our relatively recent ancestors we can match cousins a bit easier. You have 22 pairs of autosomal chromosomes you get one from your mother and father. They got theirs from their parents and they got theirs from their parents and so on back through time.
The average amount of autosomal DNA (atDNA) shared with a relative decreases with each generation you go back. Percentages are also approximate - a sibling may share anywhere from 47–52% of their DNA in common.

50% (parents and siblings)
25% (grandparents, aunts/uncles, half-siblings, double first-cousins)
12.5% (first cousins)
6.25% (first cousins, once removed)
3.125 (second cousins, first cousins twice removed)
0.781% (third cousins)
0.195% (fourth cousins)

The chart below shows we inherit about 12.5% of our atDNA from each great grandparent and about 6.25% from each of our 2nd great grandparents.
Image

Genealogy - Unfortunately this test will not add to your family tree your missing ancestors. As with ALL DNA testing you MUST have a well researched/documented family tree. There is nothing in this test that will tell you which branch of your family the match is from. Also the farther back in generations the accuracy rate decreases. You can probably find cousins that relate back 5 generations, but you won't know which generation or which line. While the test is broader that it can find a match to any branch of your line it is shallower as it will find those 2nd and 3rd cousins. Now it is possible that those cousins have done the research and you can compare notes and figure out the most likely connection.

Good articles on Autosomal Testing: http://www.dna-testing-adviser.com/Auto ... sting.html
http://genealogy.about.com/od/dna_genet ... osomal.htm
Using gedmatch.com:
http://everymangenealogy.blogspot.com/2 ... chcom.html

Put together by Jill 2011