Thursday, February 19, 2009

So long, Cousin Euclid

I'm mildly bummed. There was a really interesting discussion on cicircle recently of the origins of the Connexin-26 mutation that causes non-syndromic deafness. (Ben's deafness is caused by Connexin-26 -- see this old post.) The most common form of this mutation is a single basepair deletion of G at nucleotide position 35, hence the name 35delG. And it turns out that this particular mutation probably originated in ancient Greece. Which I thought was really cool -- as a mathematician, I'm more or less professionally obligated to venerate the ancient Greeks. I was already imagining Euclid or Pythagoras in my family tree.

Until I looked back at Ben's genetics report and realized that he doesn't have the 35delG mutation. Oh, well.

Ben has two variant types. One is a 1 basepair deletion of T at position 167; this so-called 167delT deletion has a higher carrier frequency among Ashkenazi Jews. The other is a massive 14 basepair deletion from nucleotide positions 313 to 326. The carnage, the humanity. It would be really neat to find out when and where these mutations originated. No, it doesn't change anything. I just like to think about things like this.

I'm sure my mother (a genealogist) has already uncovered lots of other interesting characters in our family tree. But no Pythagoras, alas.


leah said...

Very interesting- too bad there is no Hippocrates, Euclid, or Pythagorus in the family! I was reading an article recently on the heterozygote advantage of some Connexin 26 mutations (better healing ability/resistance to pathogens for heterozygotes). It was pretty fascinating!

We still have no clue about the cause of Nolan's hearing loss, though it is presumed genetic due to the audiogram shape and symmetry. Maybe we'll find out some day!

Lydia said...

Hey, Julia -- here's a 2002 abstract that mentions that 14 bp deletion mutation:
Also found a ref to it in (see Table 1 and ref #84) You could do some serious genealogy research!

Julia said...

Hey, erstwhile Cousin Lydia! Thanks for the references! The first one paid off big time -- the authors found 4 people in Germany with the 313del14 mutation, and I was able to read the full text of the article. (I'd seen 14 bp deletions starting at 310 and other nearby positions in the database at the Connexin Deafness site, but this was the first place I'd seen one start at 313.) Very exciting!

Leah, I just brought up Hippocrates today in my geometry course!

Madeline said...

Awww. Too bad we're not related to Euclid or Pythagoras. Oh well, I think we've got enough awesome mathematicians in the family as it is. ;)