Thursday, March 27, 2008

Is There a Connection Between Haplogroup H and Alzheimers Disease?

I came across an abstract posted earlier this month that has me wondering, "What's up with this?" Evidently there are some researchers who are looking for a possible connection between Alzheimer's Disease and the various haplogroups. Haplogroup H is mentioned as is cluster HV (Is that a subclade?). I'm not sure what they concluded from their research but you can read the abstract here:

Mitochondrial haplogroup H and Alzheimer's disease—Is there a connection?
Neurobiology of Aging, In Press, Corrected Proof, Available online 4 March 2008,
Aleksandra Maruszak, Jeffrey A Canter, Maria StyczyƄska, Cezary Ć»ekanowski and Maria Barcikowska View Abstract (specifically mentions hg H)

Additional research abstracts I found on the subject are:

Analysis of European mitochondrial haplogroups with Alzheimer disease risk
Neuroscience Letters, Volume 365, Issue 1, 15 July 2004, Pages 28-32
Joelle M. van der Walt, Yulia A. Dementieva, Eden R. Martin, William K. Scott, Kristin K. Nicodemus, Charles C. Kroner, Kathleen A. Welsh-Bohmer, Ann M. Saunders, Allen D. Roses, Gary W. Small, Donald E. Schmechel, P. Murali Doraiswamy, John R. Gilbert, Jonathan L. Haines, Jeffery M. Vance and Margaret A. Pericak-Vance View Abstract (specifically mentions hg H)

Lack of association between mtDNA haplogroups and Alzheimer's disease in Tuscany.
Neurol Sci. 2007 Jun;28(3):142-7. Epub 2007 Jun 30. Mancuso M, Nardini M, Micheli D, Rocchi A, Nesti C, Giglioli NJ, Petrozzi L, Rossi C, Ceravolo R, Bacci A, Choub A, Ricci G, Tognoni G, Manca ML, Siciliano G, Murri L. View Abstract

Mitochondrial DNA haplogroups and susceptibility to AD and dementia with Lewy bodies.
Neurology. 2000 Jul 25;55(2):302-4. Chinnery PF, Taylor GA, Howell N, Andrews RM, Morris CM, Taylor RW, McKeith IG, Perry RH, Edwardson JA, Turnbull DM. View Abstract (Specifically mentions hg H)

Do haplogroups H and U act to increase the penetrance of Alzheimer's disease?
Cell Mol Neurobiol. 2007 May;27(3):329-34. Epub 2006 Dec 21. Fesahat F, Houshmand M, Panahi MS, Gharagozli K, Mirzajani F.
"We could find that haplogroups H and U are significantly more abundant in AD patients (P = 0.016 for haplogroup H and P = 0.0003 for haplogroup U), Thus, these two haplogroups might act synergistically to increase the penetrance of AD disease." View Abstract (Specifically mentions hg H)

I must admit that I don't understand the content of most of these abstracts, except the last one. It sounds like in that study they are saying that they found more members from haplogroups H and U in the group of Alzheimer's patients they studied. I'm not sure what "penetrance of AD disease" means.

I don't know what to make of all these articles. The fact that there are multiple research teams looking for a possible connection between haplogroups and Alzheimer's Disease, with hg H coming up repeatedly in the literature, makes me tend to think that they suspect there is some kind of connection there but they haven't figured out what the connection is. Or maybe they have and I just can't figure it out from the way they're presenting it ;-)

Interestingly, late onset Alzheimer's Disease runs in my maternal line, those that carry my same mtDNA. My mother and her sister both had it in their mid 80s. My maternal grandmother died at age 70 from complications of diabetes but her sister, my maternal grandaunt, had AD in her early 90s.

What are your thoughts? Do you know of any AD in your mtDNA line?

Thursday, March 20, 2008

Book Review: Trace Your Roots With DNA

Trace Your Roots With DNA by Megan Smolenyak Smolenyak is a nice book for an overview of the field of genetic genealogy testing. It goes into detail describing the process of DNA testing and discusses what you can expect to learn from Y-DNA and mtDNA testing. Beyond that, Megan has a nice section on starting a group project and has information about where you can locate others in your same haplogroup or surname. Lots of good information here.

My Opinion: Here's another good overview book that is successful at reducing the sci-cho babble to genealogy-speak. It's a book genealogists will be able to understand without running for the dictionary. For me the most interesting parts of her book were specific cases where DNA testing was used to validate relationships, especially with mtDNA which is typically not thought to be used as such.

What's to be learned about haplogroup H: Unfortunately, nothing.

Thursday, March 13, 2008

This Is The Kind of Information Genealogists Want About Their mtDNA...

In his article, Blah, Blah, Blah on his blog The Latest in Meandering Thought..., Brian Miller writes about recently receiving his mtDNA test results. He didn't get much information about haplogroup H so you won't learn anything new from reading his post. But he did share a good bit of what I thought was fascinating information about his Y-DNA haplogroup Q. I mention this only because it's a good example of the kind of information that I think genealogists would appreciate getting when they receive their test results.
But today I found a little piece of information that I found interesting, if for no other reason than that it was personally interesting. I discovered an article that stated that the predominant haplogroup Q population is from northern Eurasia and is mongoloid in physical traits, versus caucasoid which is predominantly of European descent. Mongoloids are distinguished by "non-projecting noses, flat faces formed by forward projecting cheekbones, round eye orbits, shovel-shaped incisors, and complex cranial sutures, flattened chins, elliptic dental archs and brachycephalic (short and broad) skulls". Hm. The article went on to discuss... [More]
I get that this group is much smaller than hg H and that H's members may not have definable physical features like this group so I'm not thinking that this very same type of information is necessarily available for hg H. But I do think that this is substantive information that a genealogist might want to include as part of a chapter on DNA in their published family history.

If anyone from any of the genealogy testing companies happens to be reading this, please take my request to heart. I'm asking you to consult with the anthropology departments from a couple of different universities and see what can be said about those who migrated to Europe from the Middle East 20,000-30,000 years ago and share it with us. Not everyone wants to use mtDNA as a tool to determine ancestry. Many of us just want to know what life was like for our mitochondrial cousins of yesteryear without having to major in anthropology.

And another thing... What about the gene mutation for blue eyes... didn't that happen about 20,000 years ago too? Could it be that our "Helena" was the first blue-eyed mutant? Hmmm? Has anyone thought about that? Well... get busy and investigate! LOL!

OK. I'll get down off my soapbox and we can return to our regularly scheduled program.

Tuesday, March 11, 2008

Web Site Review:

I made a visit to the web site yesterday. This is the public database for mtDNA results. It doesn't matter which company did your testing, all are welcome to submit their results here.

This site is very straightforward and easy to use. First you register for a user account and then you can enter your information and check to see if anyone else is a match for your mtDNA. It's free :-)

I registered and entered my test results. Then I went to the "Search for genetic matches" page. You can choose how specific you want your search to be. In my case, I really only wanted to look at exact or almost exact matches. Haplogroup H is the largest group of the seven in Europe so there has got to be one whole heck of a lot of people in this group. I didn't want to have to sort through a lot of not-so-close matches.

I entered the user ID I was assigned, selected "Only compare me to users that tested both HVR1 and HVR2, factoring both into the comparison." and clicked on search. I got 110 results that are similar to mine, 29 were matches on HRV1 and + or - 1 on HRV2. There were 12 that were exact matches for my haplogroup, HRV1 and HRV2.

You can click on the user ID for each registrant and look at the information they provided. Some provided a good deal of information and even uploaded their GEDCOM file. Others provided nothing more than a name to be contacted.

I was interested in where the 12 exact matches for my mtDNA results could trace their lineage to. I was hoping to find that they were from an area of Poland close to my maternal ancestral village. Here's the breakdown of what I found.

Those who could trace their lineage to Europe and the year of birth of their oldest maternal ancestor:

East Prussia, Germany 1779
Leitrim, Ireland 1830
Greenock, Refrewshire, Scotland 1835
Netherlands 1779
Germany, late 1700s
Prussia, Germany (date not given)

Those whose lineage was in the United States and the year of birth of their oldest maternal ancestor:

Cape Girardeau, MO 1869
South Carolina 1793
Edmonson, KY 1803
Pennsylvania (date not given)

Two users gave no information.

If I go out to include those with + or - 1 variation from mine I can add:

Czech Republic 1820
Italy 1882
Wales 1842
Italy 1844
Montreal, Canada 1878
Belgium 1585
Ukraine 1855
England 1819

Indiana 1808
Iowa 1923

Six users gave no information.

These were certainly not the results I was expecting to see, but then, what do I know? I'm a newbie at this mtDNA stuff! LOL!

Well, apparently there are lines of my mtDNA scattered across the U.S. and Europe. I find that quite fascinating. The longer I ponder it, the more amazing it is to me.

I can contact the descendants of these oldest maternal ancestors if I want to. I don't think I do. Perhaps I'll change my mind in the future but for now I can't think of anything I want to ask them. It's enough just to know they are out there...

One thing I did notice was that of those who were tested for subclades (DNA Heritage, where I had my test done, does not test for this), all were in subclade H11. I checked with my good buddy Blaine on this and he said that if my exact matches are all H11 it strongly suggests that I belong to this sub-haplogroup too. So I'm going to go with that assumption for the time being. It's a good thing to know, I think. With a haplogroup as big as H it seems like it would help to have subclades to break it down a bit further.

My opinion: This is a database plain and simple. It does what it's designed to do without any distracting ads. There is no real information provided about hg H on this site but I found my visit to be an interesting one. I hope that everyone will add their mtDNA test results here so that we can all learn more about each other.

Wednesday, March 5, 2008

Book Review: The Seven Daughters of Eve

The first book that I read after getting my mtDNA results was The Seven Daughters of Eve by Bryan Sykes. Bryan was one of the first to look at mtDNA with the idea of learning about deep ancestry. He is a professor of Human Genetics at the Institute of Molecular Medicine at Oxford University.

The first 2/3 of this book is more or less an autobiographical look at Bryan's contribution to genetic anthropology research. As he describes it, "This book is about the history of the world as revealed by genetics." I would describe it as a book about the beginnings of the field of mtDNA anthropology research and it's application to those with deep (50,000-10,000 years ago) European ancestry.

Along with explaining to his readers what DNA is and what it can tell us, he also cites a few real life examples of how the information can be used. One such example involved the uncovering of remains thought to be those of the Romanov family, the last Tsar of Russia, Nicholas II, his wife and their children. He went through how mtDNA testing was used to confirm their identity.

In a nutshell, the seven daughters of Eve represent the "seven direct maternal ancestors of virtually all 650 million modern Europeans". Scientists have assigned a letter designation to each of these women's mtDNA groups and then Bryan gave the "clan mothers" corresponding women's names: Ursula, Xenia, Helena, Velda, Tara, Katrine, and Jasmine.

The last 1/3 of the book is historical fiction. Bryan took some factual information from what is known about the people who lived 50,000-10,000 years ago and created short stories about each of the clan mothers, illustrating what their lives might have been like.

My Opinion: This book gets high marks for readability. You don't need a background in genetics or anthropology to understand it. You'll come away with a good understanding of the field Bryan speaks of and why it isn't really "genetic genealogy" but rather "genetic anthropology". (I'm thinking the marketing geniuses at the genetic testing companies are really stretching things to tap into the huge market of genealogy and family history enthusiasts... the more relevant market for mtDNA tests (anthropologists) wouldn't be anywhere near as lucrative for them.) That said, it was very interesting reading and I would definitely recommend the book.

What's to be learned about haplogroup H: You can pick up some bits and pieces of information about haplogroup H from reading this book but you'll likely come away with more questions than answers.

Sykes, Bryan. The Seven Daughters of Eve. New York: W.W. Norton & Co., 2001.