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Post by Maria on Jan 4, 2007 20:59:25 GMT -5
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Post by sandy on Jan 5, 2007 14:55:17 GMT -5
I have always thought that dna tessting is amazing and approve of it being used for genealogy. THe only thing I have against it is that so far any testing in my family lines is being done on male descendants. Bummer.
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Post by Mark on Jan 5, 2007 15:42:02 GMT -5
That's because the Y chromosome in the nuclear DNA is being used to establish family ties. The Y chromosomal DNA test (usually referred to as Y DNA or Y-Line DNA) is only available for males, since the Y chromosome is only passed down the male line from father to son. Tiny chemical markers on the Y chromosome create a distinctive pattern, known as a haplotype, that distinguishes one male lineage from another. Shared markers can indicate relatedness between two men, though not the exact degree of the relationship. Y chromosome testing is most often used by individuals with the same last name to learn if they share a common ancestor. I don't really think it's prejudicial.
On the other hand, Mitochondrial DNA (mtDNA) is contained in the cytoplasm of the cell, rather than the nucleus. This type of DNA is passed by a mother to both male and female offspring without any mixing, so your mtDNA is the same as your mother's mtDNA, which is the same as her mother's mtDNA. mtDNA changes very slowly so it cannot determine close relationships as well as it can determine general relatedness. If two people have an exact match in their mtDNA, then there is a very good chance they share a common maternal ancestor, but it is hard to determine if this is a recent ancestor or one who lived hundreds of years ago. It is important to keep in mind with this test that a male's mtDNA comes only from his mother and is not passed on to his offspring.
Example: The DNA tests that identified the bodies of the Romanovs, the Russian imperial family, utilized mtDNA from a sample provided by Prince Philip, who shares the same maternal line from Queen Victoria.
What this means in short, is that the former is used more for determining lineage while the latter is more for showing familial relationships, if you get my drift. Sorry to be so wordy... ;D
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Post by sandy on Jan 6, 2007 13:48:32 GMT -5
I understood all that before but thanks for the refresher. It's still amazing no matter what type is used.
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Post by Mark on Jan 6, 2007 16:00:56 GMT -5
No prob - anytime. I actually did quite a bit of reading on the subject while doing genealogical research and am always eager to share my new-found knowledge whether you already know it or even want to know it or not! ;D
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