Genetic Ancestry Test – The Simple Science of a Genetic Ancestry Test

It is becoming increasingly common for genealogists to take a genetic ancestry test to aid in the development of their family trees. Long lost relatives have been connected, and a wealth of other genealogical and biological information has been obtained by those undergoing them. But how does a genetic ancestry test work? What are genes and chromosomes, and why is my DNA the same as someone else's? These and other questions like them are frequently put forward by those considering ancestry testing, and this article will cast a little light on the science behind a genetic ancestry test.

What is DNA, and why is it Significant in a Genetic Ancestry Test?

Every cell in our bodies except red blood cells has DNA in it, and it's basically a coded program that tells its particular cell how to function, and what functions to perform. The DNA is housed in what is known as the nucleus of the cell, which is the core. Or very centre of the cell. It is estimated that the information contained in the DNA of a single cell is the equivalent of what might be recorded in one thousand books of five hundred pages length each. It's incredibly packaged, and is done so by wrapping it into tiny strands called genes. Genes are the focus of analysis during a genetic ancestry test.

DNA is also found in what is known as the mitochondria of the cell, as well as its core or nucleus. The mitochondria are the power generators of cells, producing the energy that each cell requires to carry out the functions programmed in its DNA. The DNA housed in the mitochondria is used to specifically trace the maternal line of a person’s ancestry, as only women pass this particular strand onto their children.

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DNA is spiral shaped, and looks a bit like a railroad track made of rubber. Each strand is joined together by small segments – the rungs – made of matched nitrogenous (nitrogen Based) bases. These bases are known as Guanine (G), Cytosine (C), Thiamine (T) and Adenine (A), and between them form the alphabet of a genetic ancestry test. Results of the DNA analysis of a genetic ancestry test will be written out in various combinations of the four letters A, C, T, and G.

What Role do Chromosomes play in a Genetic Ancestry Test?

Normal healthy human beings have 46 chromosomes that are grouped together in pairs. Each one of those pairs consists of one chromosome from our mothers, and one from our fathers. What distinguishes males from females is the 23rd set of chromosomes. All others are identical except that one pair, where males have one X chromosome and one Y chromosome, whereas females have two X chromosomes. The Y chromosome found in males is the focus of a Paternal Lineage genetic ancestry test, and is analyzed to trace ancestry along the male line, as it is only passed from father to son. Because the Y chromosome alters very little from generation to generation, a genetic ancestry test can be administered to determine if two males are likely to be related.

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How to Interpret the Results of a Genetic Ancestry Test

The results of a genetic ancestry test will be returned as a string of numbers. Each number represents a repeat (match) found for each of the tested markers used during your genetic ancestry test. The results on their own have no real meaning except to act as a partial identifier for you, but comparing the results of yours to those of other individuals can identify possible relatives; determined by the number of markers matched. If numbers match at most or all of the markers used in your genetic ancestry test and that of the other individual's, it is most probable that you've found a relative.