The autosomal genome of Ötzi the Austrian “Iceman” is apparently in the pipeline (from what I can tell they’re doing the analysis right now). What can we learn from one sample? Ann Stone, who was a graduate student on the original team which recovered his body, says:
A specialist in anthropological genetics, Stone is excited by the recent news but also cautious. “It is a sample of one. For us to really say something about that period, you need a sample of 25 to 50 individuals,” she explained during an interview with Deutsche Welle, Germany’s international broadcaster.
This is fine as it goes. Worries about sample size are pretty generic and if the practicalities permitted who wouldn’t want a bigger N? But whether you should worry about sample size is partly conditional on how much the findings deviate from what you’d expect. Imagine for example that ~25% of Ötzi’s genome was of Neandertal origin. Obviously it would be great to have 25 to 50 representative individuals from this region to know whether Ötzi was atypical…but the very finding itself would be of such large effect that an N = 1 would tell us quite a bit. Similarly, one genome of a Sub-Saharan African would be very informative if you had several hundred non-African genomes as a point of comparison (because Sub-Saharan Africans have so much genetic variation which is outside of the distribution found among non-Africans).
Razib Khan’s degrees are in biochemistry and biology. He has blogged about genetics since 2002, previously worked in software development, is an Unz Foundation Junior Fellow and lives in the western US. He loves habaneros.
August 26th, 2010 at 12:56 pm
If you think of every gene as a sample, then the sample size is huge.
August 26th, 2010 at 2:05 pm
I think that she was just trying to chill out the inevitable excitement that will arise when it is found that Otzli was Jewish and related to Hitler.
August 26th, 2010 at 3:20 pm
Ha, ha, John.
I was worried there for a moment that we were about to find out something intimate about Otzi’s anatomy that we didn’t really want to know.
Otzi’s genome comes with an appearance and the things he was carrying. For instance, he was carrying a bronze age copper axe. Although it is a sample size of one, it is more interesting that a sample from bones alone.
August 26th, 2010 at 7:09 pm
Twitter Trackbacks…
…
August 26th, 2010 at 7:58 pm
@ John: I did wonder why Razib referred to him as an Austrian
August 26th, 2010 at 8:11 pm
Anybody else catch the CBC radio “As It Happens” interview with Alessandro Vanzetti regarding Otzi?
http://www.cbc.ca/asithappens/
If you can’t pick up the interview, here’s the Alessandro Vanzetti annoucement:
http://blogs.discovermagazine.com/discoblog/2010/08/26/study-was-otzi-the-iceman-buried-with-pomp-and-circumstance/
To be honest, I would love it if Otzi was carried into the mountains for burial by his friends.
August 27th, 2010 at 9:00 am
Irish. I’ll vote for his proving to be Irish.