whY-DNA

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The genetic journey began some months ago, with a fairly reasonably priced test with Ancestry.com.  Genetic testing is useful for determining one’s ancestral origins, but it is also a backdoor method for adoptees to find their birth parents or vice-versa… if both parties get tested and share their results within the same database.  Ancestry is one of three domestic companies that perform DNA testing and house databases against which DNA results can be compared to find relatives.    Some users choose to make family trees available, some provide no contact information, and some provide information but otherwise do not participate for those looking to establish connections.  Each to his own.

There are different types of tests one can take.  Autosomal DNA, which identifies the 22 pairs of chromosomes that are inherited from parents, is the most useful for people to find their ancestors and cousins via DNA matches of others who have tested.  Another is mitochondrial testing, which analyzes DNA within cells passed exclusively from mothers to all of their children, but sons do not pass it on.  This can be useful in identifying direct maternal descendants, but is more often used in identifying ancestral origins through movements of population through the centuries evidenced by commonalities in their genetic codes, referred to as haplogroups.  So, for my female haplogroup, you can see by clicking this copyrighted link and observing haplogroup T2 a general movement of my ancestors towards Europe about 20,000 years ago. I kind of like the arrows suggesting movement over time, because the static picture of information (yes, much determined from ancient remains), is more a story of “where not” rather than “where.”

As it stands, the details from those people who I matched point to Germany, England, Ireland and Scotland for their ancestors, but for any further clarification, I would need to spend another $159 to get the full sequence examined rather than just the basic branch.  This really is not helpful unless genealogy becomes a passion coupled with abundant spare time.  Currently, I and my 10 or so “matches” have a 50% chance of having a common ancestor in the last 28 generations (about 700 years).  The upgrade would boost that to a 95% confidence of being related within 22 generations – about 550 years (but a 50% chance within 125 years).  DNA testing is a business after all, but the science grows along with the combined database, a portion of which is supplied by enthusiasts who pay to have the finer details examined.

The last is Y DNA.  Aside from the autosomal “cousin” test, there’s an additional pair of chromosomes that determine gender, the mother contributing an X chromosome and the male contributing either an X or a Y .  If there is a Y, then the child is a male, and it is passed strictly from father to son.  A male, therefore, might learn a bit about surnames based on others who share the same Y DNA.  So I did that, and, at least in the one data set, there’s Needham, Fearn, Lowe (3), Blore, Oakley, Johnson, Marrison, Graves, Thompson and two Hills.  That’s interesting, but it’s not like 10 listings of a single “most likely surname.”   Why not? Well, two reasons.  One is that, like my own particular circumstance, the Y chromosome is somewhat frequently bequeathed in what genetic genealogists call a “non-paternity event.”  That’s where a son carries a different surname from that of his biological father, the kind of thing that happens when parents don’t wed or are not wed, and the child takes the mother’s surname or someone else as an adoptee.  Secondly, genetic mutations occur occasionally.  When this happens, it usually demarcates a genealogical time frame rather than a shift between each generation.  So, my closest Y-DNA match has a “genetic distance” of three.    One genealogical distance is a time frame of only 100-200 years, so… do the math.  Like the mtDNA, unless someone alive takes the test and it matches exactly across all markers (a match with a genetic distance of 0 across many, many markers), it’s not useful in identifying a living male ancestor. (And, testing all markers runs around $500).  There is the odd chance that someone is close enough to match within the last 200 years or so, with at least some chance of examining a family tree from autosomal testing to work backwards to the present.  More on that in a later post.

That doesn’t mean that it’s without interest.

So, like mtDNA, there are haplogroups assigned to the male data.  Due to population growth and those dang mutations, some of the once distinct haplogroups merged to look very similar over time.   Short tandem repeats (STR) represent part of the DNA code where a letter sequence is repeated.   For example, AGTAAGTAAGTA is three repeats of AGTA.  These have, in genealogical terms, a fast mutation rate as they increase or decrease the number of repetitions.  Additionally, they tend to back mutate periodically.  These are useful for determining how recently males are related.

But, there is also SNPs (Single Nucleotide Polymorphism), which, roughly describe a single, small change in the DNA code.  Relationship between matches is certain, but not the timeframe.  SNPs effectively form branches which themselves can be traced, which to my understanding are termed “subclades.”   And I haven’t chased that particular rabbit as far as it goes, because there is an evolving understanding of these “clades” and “subclades” as more people are tested repeated patterns identified.  

Reading professional or hobbyist groups are somewhat entertaining as numerous contentious enthusiasts debate migratory patterns of small groups of men long dead, citing theories, formulas, and tremendous amounts of conjecture.  R1b-U106 members have their own discussion group termed “The Haplogroup of Scientists and Kings.”  I might edit that to “Scientists, Kings, and Philanderers.”  But, in any case, subclade Z-156, where I belong, has an estimated origin of 2300 BC, which I assume to mean is when the mutation set now observed began to appear.  There are further subclades that exist beyond this which await only an “Upgrade” button on the company’s site.   The testing I’ve already done suggests I just missed out on the House of Wettin.  To see how geeky things get, here are the DNA credentials to join the “King’s Cluster.” 

Here’s another migratory map (click R) based on Y-DNA which pretty much says the moms and the dads flocked together.  No surprise there.  Sub note: It’s the most frequent haplogroup in Western Europe.  Information gets filtered different ways, depending on the tests, the database, and the algorithms.  Here’s a map from one site’s interpretation of my autosomal data:

Capture

That’s 47% British Isles, 25% Scandinavian (Vikings!), 21% Southern Europe and 6% Eastern Europe.  And here’s an interpretation from another site. 

Their smudge factor implies less certainty…  In any case, that’s 34% Great Britain, 23% Scandinavia, 15% Ireland, 13% Western Europe, and 7% Italy/Greece.  Which means, at the end of the day, my ancestors lie in the same continent as most everyone I know who looks kind of like me. 

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