Misc. Genealogy Articles

That leaves the nuclear DNA. We get approximately 50% of that from our father, and the remainder from our mother. Of course, the exact mix of which we get from our father and which from our mother differs with each individual (otherwise, we would all be identical twins to our siblings). So most of that DNA wouldn't help us much in tracing lineage, because the mixture varies with each individual.

The one exception relates to the Y-chromosome, which men have and which women do not. Since only men have one, that means that men get theirs from their own father, who got his from *his* father, and so on. If both my parents were deceased, I wouldn't know which of my parents any of my nuclear DNA came from (because it's a random mix), except for my Y-chromosome, which had to have come from my father.

And because Y-chromosomes are passed from father to son, we would expect them to match surnames that pass from father to son. So the Y-chromosome I carry is a "Smith" Y-chromosome, which means that any Smith men descended from my Smith ancestor should have that same Y-chromosome. This makes Y-chromosomes useful for linking families by surname. But because women don't carry Y-chromosomes, you can't test a woman's DNA to see if she is descended from someone of a given surname. You don't carry the Donaldson Y-chromosome. If you had brothers, they would. Your father did, as would any brothers he had and any sons of those brothers. And so forth.

Does that help explain the situation?

Drew Smith

--------------------------------------------------------------------

Date: Sun, 13 Aug 2006 15:00:17 -0600
From: ROOTS-L-request@rootsweb.com
Subject: ROOTS-L Digest V06 #352
-----------------------------------------------

X-Message: #1
Date: Fri, 11 Aug 2006 19:34:24 -0700
From: "Derrell Oakley Teat"
Subject: mtDNA Explainations

Excellent article to read and learn about DNA
Derrell Oakley Teat

Ancestry Daily News
Megan Smolenyak Smolenyak – 8/4/2006


The ABCs of mtDNA
by Megan Smolenyak Smolenyak

When it comes to genetic genealogy (which I often refer to as genetealogy), Y-DNA is by far the most popular type of testing--and understandably so. Since Y-DNA is passed from father to son down through the generations (just like surnames) its appli ccation is fairly obvious. But over time, mitochondrial DNA (usually shortened to mtDNA) testing has been gaining in popularity.

How mtDNA Travels Many folks regard mtDNA as the equivalent of a maternal version of Y-DNA testing and while there are some parallels, there are also some differences, and that creates a lot of confusion.

For instance, mtDNA is passed down through maternal lines, but mothers pass it on to both their sons and their daughters. The sons, however, become mtDNA dead ends and do not pass it on. This means that a brother and sister (who share the same mothe r) can both get tested for mtDNA, and that they both can serve as living representatives of their mother, their mother's mother, their mother's mother's mother, and so on. (Think of the bottom line of a pedigree chart). But when this brother and sister pa ss on, her children will continue to sport the same mtDNA, while his will have his wife's mtDNA.

Primarily a Deep Ancestry Tool Perhaps the most important aspect of mtDNA to grasp is that it's essentially a deep ancestry test, and is not as genealogically useful as Y-DNA. If you're familiar with Bryan Sykes's best-seller, The Seven Daughters of Eve, you may recall that the u nderlying premise is that 95 percent of people of European origin can trace their maternal roots to one of seven women who lived in Europe approximately 10,000-45,000 years ago.

I, for example, am from haplogroup H (haplogroups might be thought of as branches of the world's family tree--in this case, the world's maternal family tree), which Sykes dubbed Helena. Her descendants were the most successful in reprroducing. Conse quently, roughly 30-40% of those of European origin are also H. And this, in turns, means that I have millions of maternal cousins. That's not tremendously helpful to know when it comes to tackling my family tree.

Are You My Cousin? Unfortunately, a lot of genetealogy newbies fail to understand this, so once they get their results, they tend to play the matchmaking game. By this, I mean that they e-mail everyone who matches their mtDNA, share the usual name/place/date details o f their direct maternal line back to their earliest-known ancestor, and then cross their fingers hoping for someone to report back having found some overlap. But because it's such a massive fishing expedition, this hardly ever happens. (I know of one succ ess story, and in my mind, this person hit the mtDNA lotto!)

Given its limited utility, why would folks even be interested in taking mtDNA tests? One reason is simple curiosity. A lot of people are genuinely interested in knowing about their deep ancestry. So if you want to know roughly when and how your dire ct maternal line migrated out of Africa, you might take this test to find out. For most folks, this is all they will learn, but for many, it's sufficient.

Three Exceptions and...
Having just said that mtDNA tests are not very helpful for genealogical purposes, I'd like to point out a few important exceptions:

a.. First, you might be lucky enough to have rare mtDNA (taking the tree analogy a little further, you could think of this as coming from a branch or even a twig with very few leaves on it). This was true of Ann Turner, who co-authored Trace Your Roots with DNA: Using Genetic Tests to Explore Your Family Tree with me. Some people like Ann have very few, if any, mtDNA matches. Even though she is also in haplogroup H, the most common European one, she has a couple of additional mutations that reduce the number of exact matches all the way down to one. In cases like this, it makes sense to play the matchmaking game and compare notes.
b.. Second, you might be dealing with degraded remains, as is often the case with history mysteries. For instance, I recently worked on a BBC show to try to identify the two skeletons found in the turret of the USS Monitor a few years ago. In case s like this, scientists would love to use Y-DNA, but it's too fragile and doesn't survive. MtDNA, by contrast, is plentiful, so it is more resilient. It's not as precise, but it's usually all scientists have to work with. So in this case, I took the mater nal lines of the sailors who lost their lives in the USS Monitor, and traced them forward in time to find living maternal relatives to serve as a basis for comparison to the DNA extracted from the remains. This is also what I routinely do on my cases for the U.S. Army's repatriation project (to help identify remains of servicemen still unaccounted for from WWII, Korea, and Southeast Asia).
c.. Third, you may have a specific, maternally-oriented genealogical conundrum--and if you're strategic about it, you just might be able to come up with a clever way to resolve it using mtDNA testing. Theere are a few examples on pages 69-73 of "T race Your Roots with DNA." (Those who are registered at Amazon can use the "search inside this book" feature to view these pages or you can click here for a detailed version of one of the examples given). Mbr> ...A Couple of Caveats
To this list of exceptions, I now need to add a pair of qualifiers. The good news is that testing companies and avid genetealogists are working together in an attempt to refine haplogroups. For instance, when I first got my mtDNA tested several year s ago, I learned that I was H. Now I can find out that I'm H1*. Returning to the tree analogy, it's somewhat akin to learning which twig off of the H branch my maternal line comes from.

Also, mtDNA is finite. It has 16,569 base pairs, which sounds like a lot, but is nothing compared to the billions of bases found in nuclear DNA that's used for Y-DNA tests. So it's in the realm of the possible to test for your entire mtDNA sequence, which translates into very precise results.

The catch? Well, there are two. Once you have your sequence, you can theoretically play the matchmaking game again, but at prices currently in the $795-895 range, you probably won't have too many to compare against until prices come down. And I need to point out that a full-sequence mtDNA test is the first genealogical one that could conceivably give away medical secrets. Some conditions are passed through maternal lines (e.g., some kinds of muscle disorders), so your results could potentially revea l more than you'd care to know. Of course, you'd have to take your results (which are well-protected) and do some fairly intensive research or consult a genetic counselor, but in the interest of full disclosure, I feel obligated to mention this possibilit y.

Hop in the mtDNA Pool!
If you're new to genetic genealogy, I know this is a lot to absorb, so I'd suggest that you start with more conventional Y-DNA testing, perhaps joining a surname project. But if you're ready to take the next step or are just plain curious, I hope th is primer will help you understand just what you can and can't learn from mtDNA testing.

About the Author
Megan Smolenyak Smolenyak, co-author (with Ann Turner) of Trace Your Roots with DNA: Using Genetic Tests to Explore Your Family Tree (as well as In Search of Our Ancestors, Honoring Our Ancestors and They Came to America), can be contacted through h er websites Genetealogy.com, Honoring Our Ancestors, and Megan's RootsWorld.

Upcoming Appearances by Megan

a.. 02 September 2006, Boston, Massachusetts
Joint Genealogical Speakers Guild and International Society of Family History Writers and Editors luncheon at the FGS conference
b.. 21 October 2006, Ramapo, N.J.
David Ackerman Descendants 1662
c.. 11-18 November 2006, Mexican Riviera
2006 Genealogy Conference and Cruise, hosted by Wholly Genes Software
d..
e..



Terms & Conditions | Privacy Statement | About Us | Partner with Us | Contact Us
Copyright 2000, MyFamily.com.
This article may be reproduced in whole or in part for non-commercial purposes provided
that proper attribution (including author name) and copyright notices are included


------------------------------

X-Message: #7
Date: Sun, 13 Aug 2006 04:09:36 -0500
From: "ctm 007"
Subject: Re: [ROOTS-L] DNA Testing Q

Hi dee,

I think one of the best DNA companies in the market is in Houston,
Texas. Their address is:
Family Tree DNA - Genealogy by Genetics, Ltd.
World Headquarters
1919 North Loop West, Suite 110 Houston, Texas 77008, USA
Phone: (713) 868-1438 | Fax: (832) 201-7147

This company is putting on a conference concerning DNA. Here is the website:
http://www.familytreedna.com/conference_2006_reg.asp

The Conference will be held at the Sheraton Hotel in Houston, TX..
15700 John F. Kennedy Boulevard, Houston, TX 77032
For reduced room rates call 1-800-325-3535 and mention
Family Tree DNA

Carl


--------------------------------------------------------------------
Date: Wed, 16 Aug 2006 08:56:02 -0600
From: ROOTS-L-request@rootsweb.com
Subject: ROOTS-L Digest V06 #355

-----------------------------------------

X-Message: #15
Date: Tue, 15 Aug 2006 22:06:30 -0700
From: John Carr
Subject: Re: DNA Qustion
The National Geographic test is the 12 marker YSTR DNA test (paternal line) or the low resolution mtDNA test (maternal line) conducted by Family Tree DNA, FTDNA. FTDNA also offers 37 YSTR marker and 67 YSTR marker plus higher resolution mtDNA tests, plus other DNA tests. So, the question here is what do you want. The 12 marker YSTR DNA or low resolution mtDNA tests reveal ancestral 'ethnic' or tribal groupings. They are of little use for genealogy, except to identify if you have a haplotype that closely matches anyone else who has tested. National Geographic backs their test up with an SNP test if FTDNA feels it is necessary to identify the genetic population group the sample extends from, which is a great deal. Plus they give you access to a website with nice graphics and information on the spread of the human race around the globe and how your ancestors fit in.

Generally, a 37 marker YSTR test is required to tell if two men may have a common paternal ancestor within the last five generations. If they do not have a match within two steps at 12 markers the odds of a match at the higher resolution are not likely. It comes down to how much you want to spend. It is cheaper to go directly to 37 markers, but lower immediate cash outlay to start with 12 markers. Same applies to low or high resolution mtDNA tests.

The 67 marker test should be used primarily to resolve issues within a couple generations for large groups sharing a common haplotype and known genealogy.

Please write me directly if you have additional questions.

John Carr
Administrator Carr Surname DNA Genealogy Project.

==============================================================