DNA Ancestry Tests – Understanding Y-Chromosome DNA Ancestry Tests
DNA ancestry tests that examine our Y chromosome are used to determine if any two or more males are related to a common male ancestor. Because the Y chromosome is only passed from father to son, females do not have a Y chromosome, and hence cannot benefit from this particular type on DNA ancestry test. However, just because you may be female, don't overlook the valuable information presented in this article. It may help you advise a father, brother, cousin, uncle, or friend as to whether they should undergo a Y Chromosome DNA ancestry test.
Y Chromosome DNA Ancestry Tests
The Y chromosome is part of the single chromosomal pair that men and women do not have in common. The two sexes each have 23 pairs of chromosomes, 22 of them the same, except that in that one pair; males have an X and a Y chromosome, and women have two X chromosomes. This may sound a bit complicated, and given the intricacy of molecular and genetic research, we might feel that DNA ancestry tests are also complicated. If we separate them as we have done here however, and examine them one at a time, it makes it easier to understand the complexities, and remove some of the mystery surrounding DNA ancestry tests. Understanding a bit more bout the Y chromosome can help to do this.
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Scientists have discovered that not all DNA is used to instruct our cells, some seem to just hang about our bodies with no real purpose – they labelled this "junk DNA", and initially thought it would be of no value in DNA ancestry tests. However they soon realised that this junk DNA contained characteristics which aided in distinguishing individuals from each other, and consequently could identify individuals. This is why genetic testing is so useful in criminal investigations. As scientists continued to probe into the Y chromosome, they found that; not only could they define an individual, but larger populations or groups of individuals with similar characteristics. They also found that the Y chromosome changes very little as it is passed from generation to generation, making it invaluable for tracing the paternal line of a person's ancestry.
The Process of Y Chromosome DNA Ancestry Tests
DNA ancestry tests of the Y chromosome begin with a simple cotton swab being used to take a sample from inside the person's cheek. This collects cells from the inside of the individual's mouth which serve as the source for DNA ancestry tests. The swab is sent to a laboratory where the DNA is extracted using a scientific process, after which thousands of copies of the DNA are made which can be used in future DNA ancestry tests. After making copies, sequences of DNA at exact locations on the Y chromosome are analyzed. These sequences are known as DNA markers, and each marker is given an individual name. DNA ancestry tests compare the number of times sequences repeat themselves, and compare that with the DNA markers for other males. If the DNA of each male has say, 11 out of 12 compared markers the same, there's a good chance that they are related. The more markers any two DNA samples have in common, the more likely the people involved in the DNA ancestry tests are related.
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Finding out the Results of DNA Ancestry Tests
Once the results of DNA ancestry tests have been compared, the lab will determine the probability of the two individuals being related by determining how often a change may occur in a marker over time. The DNA company does this for you, and then provides you with a chart or written instructions on how to compare two results. Remember that genetic ancestry testing is a science, though it is not perfect. The results of DNA ancestry tests indicate the probability of two individuals being related, not the certainty of it. Also, sometimes mistakes are made, or samples are corrupted, and you may need to be retested to make certain of any results being accurate. DNA ancestry testing is still in its infancy, new research is being done on techniques and procedures everyday, and could change the way in which results are interpreted. Keep these things in mind, and you’ll be better equipped to understand the results of yours or anyone else’s DNA ancestry tests.