The unraveling of the double-helix DNA structure was first accomplished just over 50 years ago (April 1953) by scientists James Watson and Francis Crick. They received a Nobel Prize in 1962 for their monumental legacy. Subsequent decoding of the biological blueprint to life has led to breakthroughs in crime investigation, medicine and genealogy. YES, GENEALOGY!
Most of us are now quite familiar with forensic scientists demonstrating the value of DNA in solving crimes. DNA analysis has also been vital in verifying paternity, indicating the likelihood of inheriting life-threatening or disabling diseases, as well as responsible for break-troughs in medical research. The same technology can now also be used by family historians to make physical connections with their ancestors, not by having centuries-old relatives exhumed, but by a simple comparative analysis of cheek cells from living descendants of our ancestors.
Family historians often find themselves 'hitting the wall', after thoroughly researching every known and available genealogical record. Researchers may find they are unable to verify genetic links to ancestors, especially when the ancestors in question emigrated from overseas several centuries ago. Records may be incomplete, destroyed or lost. In many cases, our ancestors lives may not have been well documented. Nuances in surname creation and spelling of the surname down through the years may have caused confusion and lost genealogical trails. And finally, oral family histories that we depend on in some cases may be faulty.
In some cases, no matter how much effort, time and money are put into a family history project, the research results in a 'dead end'. Many researchers give up at this point or perhaps wait for dozens of years hoping a missing piece of documentation will show up. Now, thanks to advances in genetic science, the walls are beginning to crack as genealogists turn to DNA analysis to develop confirmed links with their ancestors.
Genetics testing is the greatest new tool available to genealogists since the creation of the Family Tree! After all, DNA is the Gene in Genealogy!
Recently, it has become increasingly apparent that we are all related, and I don't mean just those of us with the same surname in our family tree. The question is not are we related; but how far back in time is our common ancestor. Some day, the science of genetics is going to use our DNA to help structure our basic family tree far beyond what we can do with standard generational research using historical documentation. For our purposes today, DNA testing can already tell us if one Kleiser descendant is related to another Kleiser descendant via Y-chromosome testing.
To learn more about the wonderful new world of genetics testing in support of genealogy, please read on. A number of links have been provided below to help you understand why genetics testing is rapidly becoming a great tool for genealogists, to tell you everything you ever wanted to know about genetics and genetics testing.
Why is the Y-Chromosome Important to Genealogists ?
The Y-chromosome is passed down from generation to generation (father to son) normally unchanged. The very minor changes that do occasionally occur at random (usually only after many generations) are actually very helpful in assessing the results of the DNA test. The Y-chromosome is the only human chromosome that escapes the continual reshuffling of parental genes with every new generation. It is this unique characteristic of chromosome 23 that makes the Y-chromosome so important for genealogists.
For any particular individual, it is a random chance as to which parent’s chromosome (and its associated DNA) will be inherited. For example, one or more of the genes in one of the human chromosomes determines the child's eye color. Brown is dominant over blue, so if the child inherits a brown eye gene from one parent and a blue eye gene from the other parent, the child will have brown eyes. Because eye color is a visible characteristic, you may be able to determine (guess) which parent provided the brown eye gene to the child. However, in most cases, because the genes are inherited at random in every generation, for any given characteristic of your makeup, you will typically not know whether the activated gene in the child came from the mother or the father.
Men can only inherit the Y-chromosome from their father, because the mother doesn't have a Y-chromosome (that's the difference between boys and girls!). A man passes down his surname and his Y-chromosome DNA to his son. In most Western countries since the middle ages, the surname has been patrilineal. So, here in the 21st century we can test the male Y-chromosome and know with a great deal of certainty the identity of the Y-chromosome that the man's male ancestors had over 500 years ago when surnames were first used. We don't have to dig up our ancestors to test their DNA! In fact, the Y-chromosome deteriorates rapidly after death, so it is unlikely a DNA test could determine one’s Y-chromosome profile for someone who is no longer living.
What Results are Obtained ?
A 12, 25, 37 or 67-marker test is conducted on the cells retrieved from your cheek. The more markers tested, the more certain we can be of a match (genealogical link) between two or more participants. Markers are specific loci on the genes within the human chromosome. The markers (12, 25, 37 or 67) that are examined have been selected by the 'experts' to best represent the unique nature of the Y-chromosome. The Y-chromosome has many 100s of loci, perhaps several 1,000 all together, but the scientists have been able to narrow down the number to a few loci that they believe are the most meaningful for genealogical test purposes. In other words, when we compare the specific test results for each marker for one man's DNA against other men, we are most likely to determine if there is a recent common ancestor using as few as 12-markers (although 25 or more markers provides results with greater probabilities). In some cases, the 12-marker test will suffice; however, in many cases, we may need to run a more definitive test using 25 or more markers to be very sure of the results. The more markers used for the test, the more likely (higher probability) there is a recent common ancestor when all the markers for both men are tested to be identical (12 for 12, 25 for 25, 37 for 37, and 67 for 67) or very nearly identical (11 for 12, 23 for 25, 34 for 37, and 62 for 67). Obviously the more markers tested, the higher the cost of the test, although DNA testing for genealogical purposes is now quite reasonable.
The test results by themselves won't mean much to the casual observer. In fact, you can't plug your results into a computer database and have it print out your genealogy. Someday, this may be possible, but not today. That's another whole different story. Anyway, what we can do today is compare a man’s DNA test results with the results of other men who have been tested in the same manner. When the results are an exact match, we know that there is a 99% probability that the two men tested have a recent common ancestor.
DNA MOLECULE
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