Autosomal Dna Testing Genetic Test

Many people wishing to find out more information about their ancestry may choose to undergo DNA testing. There are three types of tests: mitochondrial (maternal line); Y-chromosome (paternal line); and autosomal (a combination).

Autosomal DNA is made up of the 22 pairs of non-sex-linked chromosomes found in the nucleus. They control physical characteristics such as hair color, eye color and height.

When a person undergoes an autosomal DNA test (sometimes called BGA – Bio Geographical Ancestry – testing), their genetic history is researched by a complete scan through all the chromosomes. The DNA that has portions contributed by both parents is analyzed to give a genetic snapshot.

Autosomal DNA testing is beneficial because there are no gender limitations, and you can verify or establish nuclear family relationships with specific relatives, such as a sibling or a grandparent.

Uses of Autosomal DNA Testing

The most common use for autosomal DNA tests is paternity tests. Autosomal research is also used in extended family testing. These family tests use Codis markers. Police departments and forensic labs use them as well.

Another type of autosomal DNA testing is called biogeographical ancestry testing. It tests all of an individual’s genetic contributions for specific markers that designate geographic heritage. Unfortunately, the margin of error for these tests can be as high as 15 percent. The major ancestry type is usually not contested, but minority types can be far less accurate.

Cost of Autosomal DNA Tests

Basic autosomal DNA tests cost about $200 and categorizes the client into percentages of European, Sub-Saharan African, East Asian and Native American ancestry. Usually, for an additional fee, you get a little more detail?percentages of Northern European, Mediterranean, Middle Eastern and South Asian ancestry. Finally, some companies offer an in-depth European test for an additional cost.

Limitations of Autosomal DNA Testing

One of the limitations of autosomal DNA testing is that you can only test as far back as two generations (grandparents). Scientists are hopeful that with additional research, earlier generations can be investigated through autosomal DNA tests.

Autosomal DNA testing is less effective than other ancestry tests because DNA is diluted with each generation. Autosomal DNA tests are most effective when used in combination with other forms of DNA testing, such as mitochondrial or Y-chromosome testing. Mitochondrial DNA (mtDNA) testing is done to reveal information about an individual’s direct maternal line. Y-chromosome testing does the same for the paternal line. They both differ from autosomal testing, which combines the two and researches portions contributed by both parents.

Another problem with autosomal DNA testing is that some groups of genes are inherited together, meaning an individual may receive more genetic material from one parent. Over time, some genetic traits may fade across the generations. In other words, an individual won’t necessarily be 30 percent Irish just because his mother was 60 percent Irish. He may only receive 20 percent Irish genes, while his sister receives 40 percent. Scientists do not yet understand how inheritance traits are selected to be passed on to children.

Resources

Eugene, M. (n.d.). Your guide to DNA ancestry testing. Retrieved September 11, 2008, from the Corrupt Web site: http://www.corrupt.org/data/files/dna_ancestry_testing/

Ferguson, P. & Crain, J. (2008). Autosomal DNA testing and analysis. Retrieved September 11, 2008, from the Historical Melungeons Web site: http://historical-melungeons.blogspot.com/2008/03/autosomal-dna-testing-and-analysis.html

GeneTree. (n.d.). What is autosomal DNA? Retrieved September 11, 2008, from the GeneTree Web site: http://offers.genetree.com/landing/auto.php

Relative Genetics, Inc. (2007). DNA for the genealogist. Retrieved September 11, 2008, from the Relative Genetics Web site: http://www.relativegenetics.com/relativegenetics/tutorial/testing_for_genealogist.htm