DNA testing has revealed that the human body has more than sixty different types of cells. These cells include red and white blood cells, gland cells, hormone secreting cells, and many others. Important to DNA testing is that DNA is contained in every one of these cells, and that DNA (Deoxyribonucleic acid) can provide genealogists with links to their past. There are also various types of DNA, and we'll now take a look at how those various forms of DNA are used in DNA testing.
The types of DNA that are valuable to genealogists are Mitochondrial DNA, Autosomal DNA, and Y-Chromosome DNA. These different types of DNA are all analyzed in DNA testing, and each one has its own particular value. They are all contained in the cell nucleus or center, albeit in different areas within that nucleus, yet each one can determine a variety of factors concerning one's ancestry. Let's take a close look at each of these different types of DNA, and their particular usage in DNA Testing.
DNA testing that analyzes the Y-chromosome DNA in our cells is used whether or not two males possess a common male ancestor. Y-Chromosome DNA is passed only from father to son, and consequently females do not even have a Y chromosome. This being said, women should not overlook the potential value of Y-Chromosome DNA testing, as they may be able to advise a male relative whether or not Y-Chromosome DNA testing may be of benefit to them.
DNA testing of the Y-chromosome begins with a cotton swab being utilized in order to retrieve a sample from inside a person's cheek. This swab collects cells from inside of the mouth which will then be analyzed through DNA testing. The swab containing the collected cells is then sent to a laboratory which extracts the DNA using scientific technology, then creates multiple copies of that DNA which can be stored and used for future research. Having made copies of the DNA, the next phase of DNA testing involves examining DNA sequences at exact locations along the two strains of DNA belonging to the two individuals. The points along these sequences are known as markers, and if the two strains of DNA have similar markers, there is a good chance that the two subjects of the DNA testing are related.
DNA testing of Mitochondrial DNA is similar to that of Y-chromosome DNA testing in that; strains of DNA from two individuals are compared in order to detect similarities within them. The difference of course is in the type of DNA analyzed; the Mitochondrial DNA revealing connections on the maternal side of the family. DNA that is only inherited from the female parent is analyzed and this type of DNAS testing can be administered to males and females, as it is passed to all offspring.
Mitochondrial DNA testing is much better than Y-Chromosome analysis for establishing connections over longer periods of time, and is able to determine the probability of two people being matched past 52 generations to within a 50% probability.
Autosomal DNA testing is used traditionally to confirm paternity, but may additionally be useful in forensics investigations and for researching one's ethnicity. It is generally used to examine the relationship between people who have more than one common recent ancestor. Autosomal DNA testing has shown that particular ethnic groups have specific common DNA markers. Upon identifying enough common markers, scientists can determine the probability of a person belonging to a specific ethnic group. This form of DNA testing is very valuable in identifying Jewish, African, Native American and Asian ancestry.
The one possible disadvantage of Autosomal DNA testing is dependant on the fact that DNA recombines differently in each of us. Although all of us inherit one chromosome from each of our parents, they re-combine within us in various percentages. Your Autosomal DNA may recombine as 30% of your mother's and 70% of your father's or in a 60% - 40% ratio. DNA testing of your siblings could reveal a different ethnicity than your own as their DNA may have combined in a different ratio. Autosomal DNA testing remains an imperfect science, though progress is being made on an almost daily basis.