Yep, there’s a gene for these traits, and more. The same gene, named EDAR (short for Ectodysplasin receptor EDARV370A), it turns out, also confers more sweat glands and distinctive teeth and is found in the majority of East Asian people.
This is one of the results of the National Geographic’s Genographic project. This mutation found at location rs3827760 on chromosome 2 occurred about 35,000 years ago. It apparently has conferred some advantage to its carriers, because it is found in the majority of Asian people today. We don’t exactly know why that happened, but maybe ancient male Asians preferred thick haired, small boobed and sweaty women. Or maybe those women survived when women with more body fat (yes, boobs are fat, sorry guys) and who could sweat less perished.
This New York Times article discusses the experiments performed to verify that this gene in fact does confer those traits. The scientific article itself is available in the journal, Cell although it’s behind a paywall.
Want to know if you carry this trait? If you’ve tested with either Family Tree DNA or 23andMe, you’re in luck.
Download your raw results file and open the file using any tool. Generally, a spreadsheet or Notepad will be your preferred methods. Then using the search function of the tool you’ve selected (ctl+f for Notepad or Excel’s find function) search for rs3827760. You will see two letters comprised of either T, A, C or G. If you have a G shown for either letter at this location, then you carry this particular mutation.
If you carry this mutation, you’ve probably already headed for the mirror. You’ll know already if you have small breasts, if you’re a female, believe me. You may never have thought about thick hair shafts, which isn’t to be confused with lots of hair. And your level of sweatiness is just what it is. I’ve never even considered that there were different sweatiness levels. But what about Asian teeth? Well, that trait is called sinodonty and here’s a nice wiki article and another nice article, with examples, here. If your teeth are shovel shaped, meaning the backs of your upper 4 teeth are shaped like a spoon as opposed to straight, then you have this trait.
So are you wondering what this might have to do with genetic genealogy? Well, if you carry this gene, then you obtained it from some Asian ancestor. If you’re in America and not of Asian ancestry, then there are pretty much only two routes. One would be Native American ancestry and the second would be the population or invasion of Europe by Asian groups, such as the Mongol Hordes and the Huns. Your genealogy will have to be your guide as to which source contributed this gene to your ancestors, and ultimately to you.
Oh yes, and one last thing, this mutation isn’t the only one involved in at least some of these traits, specifically the teeth. I don’t carry the G and I do have some of the Asian teeth characteristics. I don’t have thick hair shafts which makes sense since EDAR is primarily associated with this trait. And, well, I’m just not discussing the boobs and sweaty traits (and my husband is utterly forbidden to comment)…..TMI:)