Monday, November 23, 2009


When new scientific research is released, 23andme updates our genetic info with so-called “clinical reports”. The latest one of these didn’t please me at all.

The reason is I was told that my genetic risk of having something called atrial fibrillation (AF) is higher than average (20.5 percent instead of 15.9 percent in the general population). The estimated hereditary component of AF is around 60 per cent, which means that genes weigh more than environmental factors.

AF in itself is no big deal, but being a type of cardiac arrhythmia – and especially when combined with certain other risk factors (like hypertension or diabetes) – it increases the risk of having a stroke. And that I certainly find worrisome.

AF symptoms: palpitations (racing heart, which I experience not unfrequently); lack of energy (who doesn’t?). All this to say that although it doesn’t mean I have AF, it makes me wonder.

One way to reduce the risk of stroke is treatment with drugs that dilute the blood, preventing potentially dangerous clotting when the arryhtmia hits. One of those drugs is warfarin – and the biggest problem with this drug is determining the right dosage for each person. Too much of it can lead to internal bleeding, to little won't serve its purpose.

Precisely where warfarin is concerned, 23andme also provided me, some time ago, a piece of relevant information about the most likely reaction I should have to it if I ever had to take it. Once again, my genes say that I am apparently more sensitive than average to this drug – which means that I might have to take smaller quantities of it to be on the safe side.

For the first time since I had my genes tested at 23andme, I feel the need to talk about this to my doctor when I next see him. Is this the empowerment they’re always "selling" us as being THE big promise of personal genomics? For the time being, I feel mostly a little unnerved.

Monday, November 9, 2009

Good news

I received the following message, posted on Family Tree DNA website, through one of the mailing lists I subscribed:

"An academic research team, including our chief mtDNA scientist Dr. Doron Behar, is collecting mtDNA haplogroup H full sequence results for a population study. The study will update the haplogroup H tree and provide information on the distribution of subclades. Every sample used will help the research team to develop and resolve the H haplogroup tree. Your mtDNA full sequence results qualify for possible inclusion in this study."

Which means that Israeli scientist Doron Behar and his team are going to start analysing the details of the mitochondrial haplogroup (matrilineal descent) that goes by the letter H, to which I belong (my sub-haplogroup, or subclade, is H7, as I have already mentioned here). Finally!

I heard about Behar’s work for the first time in 2006 (he was then at Rambam Medical Center in Haifa), when he and his colleagues published an amazing paper in the American Journal of Human Genetics. As I already wrote in a previous post, through the genetic study of mitochondrial DNA, they discovered that nearly half of Ashkenazi Jews (“German” Jews) in the world today are descended from just four “founding mothers”, most likely Hebrew women from the Middle-East, who lived in Northern Europe, in what is now Germany, one to two thousand years ago.

Apparently, Behar, who as the message says is chief mitochondrial DNA scientist at Family Tree DNA (, has now decided he has enough data to go on, from clients there, to undertake the same kind of study on haplogroup H. And he is inviting participation.

I think this is a fantastic example of how scientists can put to good use individual genetic data (without disclosing anybody’s identity) to further our understanding of the migration routes of human populations through the ages.

The message, though, is only visible to those who have had their mitochondrial DNA fully sequenced at FTDNA - and who belong to mitochondrial haplogroup H.

Since I tested with 23andme (which does not offer full sequentiation of mitochondrial DNA), I won’t be able to participate personally. But I’m really curious about what the results will reveal about my own past.

Image: Mitochondrial haplogroup H tree - Fonte: