Seeing Ötzi through our eyes

By Razib Khan | March 8, 2012 11:29 pm

Dienekes got his hands on Otzi’s genome finally, and decided to confirm some suspicions. In general no great surprise, though I think the number of SNPs he used (44,000) is a little on the low side for the questions he was asking. But the details here aren’t too relevant because all the available evidence points to the “Iceman” being affiliated with modern day Sardinians, of whom we know much more with many more markers.

In any case, he points out that if you run ADMIXTURE you tend to see that Sardinians, and to a lesser extent Basques, are lacking in some ancestral components. One phenomenon which is implied by this is that these populations which are less “cosmopolitan” may reflect more ancient patterns, when there was less admixture. I’ve indicated this myself when it comes to non-Muslim minorities in the Middle East. But one caution I would immediately make is that we are judging the variation of smaller populations by the yardstick of larger populations. Distinct and less numerous groups, such as Sardinians, may show less ancestral cosmopolitanism in part because the reference populations which could be used to adduce such a state no longer exist.

To give an extreme example the Onge of the Andaman Islanders often pop up as a very distinctive genetic component. But what if there were many more related populations in the data sets generating patterns of variation? We might see that the Onge themselves are composites! The idea I’m trying to get across is that we imagine the past was demographically pristine. But if it wasn’t, then our attempts to make inferences become all the more difficult.

CATEGORIZED UNDER: Uncategorized
MORE ABOUT: Ötzi
  • http://www.buildinghistory.org/distantpast/ Jean M

    So true.

  • Patrick Wyman

    Really excellent point. My hope is that we get a temporally intermediate sample with which to compare Otzi at some point in the near future; Kristina Killgrove is working on a Roman-period DNA project, but I’m not sure if she intends to do any genome analyses or just discern haplotypes from her samples.

  • http://www.isteve.blogspot Steve Sailer

    So, lots of people in Europe back then were like Sardinians today?

    What are Sardinians like today? I ask because I really don’t know …

    You never hear much about Sardinians. There’s a famous Corsican we’ve all heard of, but there aren’t many famous Sardinians. A Sardinian lady won the Nobel Prize in Literature in 1926, but I have no idea who she was. Gramsci was born in Sardinia, but his family were Catholic refugees from Albania.

  • Eurologist

    I am not as pessimistic. I think Europe is sufficiently big with wrinkles at the fringe that even two or three time periods of severe mixing in the core has left sufficient structure and information at the edges. The problem with Europe is not that – it is that it likely started out rather homogeneous in the Gravettian in the first place, over a huge scale (from France to the Ukraine and parts of Urals, with some clines, of course), and then got twice re-settled post-LGM by pretty much the same people, and then again during the neolithic by highly-related people (some NW Anatolian/ Thracian/Balkan mixture – again with a strong cline).

    Let’s compare this to Austronesia – a currently hot topic. There, within the past 6,000 years or so, language, archaeology, and genetics draw the same picture of the spread of settlement. Why is it so easy, there? Because “Mongoloid” genetics and Papuan is about >=50,000 years apart with no contact until rice farmers pushed south – not the ~25,000 max between Europe and West Asia, with continuous gene flow before and after in *both* directions. However, if several distinct populations can be made out in Europe with very specific East-West clines both in the North and in the South, as is the case, *my* bet is that these populations predate the neolithic.

  • Justin Giancola

    ^ Good post Eurologist.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    #4, the problem is that you need good reference populations. if you have a thorough admixed present day set of populations it isn’t always to easily reconstruct ancient populations when one of the ancient populations can not be found in ‘pure’ form (which is the case for austronesian + oceanian admixing). see:

    http://www.nature.com/nature/journal/v461/n7263/full/nature08365.html

    i pointed this out to you before. it’s not a trivial objection, though it can be overcome (again, see above). i assume though that aDNA will make some of these issues less problematic.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Gene Expression

This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

ADVERTISEMENT

See More

ADVERTISEMENT

RSS Razib’s Pinboard

Edifying books

Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »