October 17, 2011

Tyrolean Iceman week is upon us! (and some migrationist thoughts)

After a long wait, this week we are likely to read (and for the lucky few, hear) the long-awaited results of the genetic analysis of Ötzi, the Tyrolean Iceman. The talk on "Sequencing the Tyrolean Iceman" is scheduled for October 21 during the MUMMIES FROM THE ICE, 2nd BOLZANO MUMMY CONGRESS.

Thanks to intelligence from one of my readers, we already know that the Iceman belonged to Y-haplogroup G2a4. My experience with similar publicity bonanzas leads me to believe that the announcement at Bolzano may coincide with a major journal publication, but I have no inside information. Well, Friday is the day when the next issue of Science is due, so I'll take a bet on that journal having an Ötzi special this week. But, even if I'm wrong, there are likely to be media stories from the mummy congress itself; we will soon find out more.

(If any kind souls want to tip me, on promise of absolute confidentiality, feel free to do so: my e-mail's at the bottom)

Why is Ötzi so important? We already have genome sequence data on a ~4,000 year old Paleo-Eskimo, and even older Neandertals and Denisovans. Ötzi, at more than 5,000 years, will become the oldest Homo sapiens sequenced so far.

From a place like Europe, we almost never get anything other than bones and teeth from that period. An ice mummy is a real treasure, as it contains non-osseous tissues preserved in a natural refrigerator. Ötzi is likely to yield as good an ancient DNA genome as we are likely to get from prehistoric Europe anytime soon.

And, Ötzi's age is equally important, since he lived during the early Copper Age, at a time when humans in Europe transcended the use of bone and stone in their tool-making, and started using copper. Humans had used metals before (including gold and iron) in a haphazard way, but it was during the Copper and subsequent Bronze Age that there is clear evidence that metalworking began to transform society.

Ötzi's genome will be extremely important for a different reason: for a long time a conflict has simmered in archaeology between idea diffusionists, demic diffusionists, and migrationists.
  1. Idea diffusionists aka proponents of acculturation propose that ideas (such as the idea of crop-raising or metal-working) spread without large movements of people. They predict that Europeans did not change much since the Paleolithic, and Neolithic/post-Neolithic processes have little affected them.
  2. Demic diffusionists propose that humans behave like mindless automata, random walking across the landscape, mating with whom they find, and filling up a continent by the accretion of millennia-long processes of diffusion. They predict that Europeans are a fairly smooth cline of Neolithic+Paleolithic constituent elements from southeast to northwest.
  3. Migrationists adhere to an older and much-maligned arrows-on-the-map paradigm, whereby humans intentionally decide to move from A to B, even across great distances. According to this idea, colonists sometimes mix with/sometimes kill/sometimes avoid pre-existing inhabitants. Migrationists predict that prehistoric Europe was a dynamic patchwork of genetic-cultural units entering the continent from different routes at different times, gradually forming the cornucopia of its proto-historical ethnic groups.
It's been about two years since I came out as a migrationist. In my view, the colonization of Europe was less a random process and more akin to the much later colonization of the Mediterranean and Black Sea by the Greeks, and of the Americas by Europeans. We can envision initial forays of exploration, prompted by either curiosity or tales of strange sights and great riches (be it the riches of Marco Polo's East, El Dorado, the Golden Fleece, etc.). These were followed by colonists, either pushed from their homelands by social/economic malaise, or pulled towards their destinations by opportunity, establishing long-range communication/trade networks. Finally, more people could flow along the established routes in a directional, intentional flow of people.

Most of the ancient DNA published in the last few years has tended to support the migrationist paradigm. Indeed, we are uncovering even weirder data points every time we look. Who would have thought a few years ago, that Australian aborigines would show ties to Siberia, some prehistoric central-eastern Europeans to modern East Asians, and neither Mesolithic nor Neolithic Europeans any clear ties to modern ones?

It seems that the surest bet is on the unexpected, so I am hopeful that the Tyrolean Iceman will have some surprises in store for us; these may upset existing paradigms, but will pave the way for new ones.

15 comments:

Pascvaks said...

Ditto!

PS: The occupation of the Western Hemisphere (pre-European) shows better the "how" of it and puts a quick end to the diffusionists, demic diffusionists, and migrationists controversy. But Europeans (and their kin) love to argue, so maybe not. Anthropology is getting soooooo touchie-feelie and whimsical; it must be the math, no one seems to like doing math anymore.

mooreisbetter said...

(Google is having an error w comments, sorry if this came our 3x).

A great post by a great writer (Dienekes). You show again and again why this blog is the best-written, best-explained anthro/genetics blog on the planet.

Comparing any migration to the New World colonization is valid, since we have a clear historical record for what happened in the New World. However, one must always remember that the Spanish and Portuguese settlers of the New World had (1) much more advanced and quicker modes of transportation to their destination; and (2) much higher populations to draw from than those in ancient times.

Onto Hg G2a. Looking at the modern distribution, I think we MUST conclude that G2a might not have originated or expanded in the Near East. As I have posted before, high numbers in an isolated area are typically considered the results of Founder Effect, i.e., five guys with diverse Hgs sail to Sardinia. Four die.

The incidence of Hg I-M26 is universally thought of to be the result of Founder Effect in Sardinia, NOT a Sardinian origin. M26 has (depending on who you trust) an Italian, Southern French, Cantabrian, or even Cardial Pottery Maker (Anatolian) origin.

Back to G2. Some scientist visits the Caucasus, an extremely isolated place, with dozens of odd languages and ancient relic populations nestled in each valley. That scientist publishes that one tribelet of Georgians is 80% Haplogroup G. The next study publishes that some other isolated triblet of Georgians is 80% J2. (True story).

People use this to opine that G2 originated near the Caucasus. They reject this argument that R1b originated in Western Europe, advancing all kinds of creative theories to explain its 80% frequency in Ireland, the latest being that "when a wave progresses, it is most intense at the farthest from its source." (In so many words).

G2 is present in ALL isolated refuges of Europe. Pyrenees? Check. Wales? Check. Appenines? Check. The Alps? Check. Sardinia? Check. The Caucasus? Check. All places where we have records of populations fleeing to.

So, if you are looking for the "original" Europeans, one has to conclude that G2 could be a candidate. Yes, it still could have come in through an Eastern Route -- but ALL Hgs came into Europe through an Eastern Route.


I posit simply that Hg G came into Western Europe earlier than anyone thought. As men bearing Hg F came out of Africa, some men evolved into G and entered Europe. NOT with agriculture, but before it. I am talking millennia before.

I posit that R1b spread from a homeland near Basque country or Bretagne or even within Great Britain, and that its expansion was not due to conquest or IE languages, but simply the evolution of LACTOSE TOLERANCE, which led to bigger, healthier populations, quickly.

This is the most parsimonious conclusion: Basques are a pre-IE population. They are high R1b. Basques are the most lactose tolerant on the planet.

Even the distribution of Beaker people is parsimonious with this. Anyone considered that those chalices were a high-status symbol indicating that "we can drink milk and you cannot?" Or a semi-cult of worship of things bovine?

Think about this. The oldest skeletons in Europe have all typed G2. That to me is strong evidence of aboriginal. The G2 skeletons from Treilles (supposed farmers and pastoralists) shocked the world when they typed as Lactose Intolerant.

R1b on the other hand -- well, no one can explain its distribution. But for the very strong circumstantial reasons I detailed above, lastose tolerance and a subsequent population expansion might be all we need.

Gioiello said...

Even though Ötzi came out a Caucasian in his autosomal data, would your hypothesis be demonstrated? I think not. We should have the data of those who killed him and of others: they probably considered him a foreigner, an outcast. It is possible that he was a Caucasian metalworker migrated to Italian ores, even though the link of the merchants of obsidian from the Aegean Sea (and Italy) from 15000YBP should be kept in mind, then the presence of G2a in Western Europe from very ancient times, and one centre of diffusion of this haplogroup is in Sardinia and it isn’t said that the Caucasus were its place of origin, even though now, that we have mt K3 besides K1 and K2 , and K3 is from Caucasus, it is possible that the K* of Ötzi was from Caucasus more than from Western Europe (even though I think that K, from U8b/K, is clearly from Western Europe in its origin).
I think having demonstrated in my postings that the supposed Middle Eastern mt-haplogroup like R0a, HV4, HV1a’b’c etc. come probably from Italy (and between the LGM and the Younger Dryas).
And what will you say if Ötzi’s autosomal were linked to Sardinians or Tuscans and not to Caucasians?

German Dziebel said...

What about Otzi's HLA? Last time I followed it was shown to belong to a type that's rare in Europe but frequent in Eskimos and Amerindians:

http://www.ncbi.nlm.nih.gov/pubmed/11592925

terryt said...

"In my view, the colonization of Europe was less a random process and more akin to the much later colonization of the Mediterranean and Black Sea by the Greeks, and of the Americas by Europeans".

Yet there are still many who bitterly oppose the idea that Y-hap O moved into SE Asia from further north around the early Neolithic (I've just been arguing with Maju).

Onur said...

What about Otzi's HLA? Last time I followed it was shown to belong to a type that's rare in Europe but frequent in Eskimos and Amerindians:

http://www.ncbi.nlm.nih.gov/pubmed/11592925


That is just a single genetic marker. Just a single genetic marker does NOT give any reliable information about ancestry and relationship to other populations, so it does NOT constitute evidence. It is NO different from Arnaiz-Villena "studies". For example, Arnaiz-Villena too used just a single genetic marker when "calculating" the genetic relationship of Greeks to other populations (in fact, he used the exact same genetic marker as the one used in the paper you gave link to) and arrived at a completely WRONG conclusion about Greeks.

German Dziebel said...

"That is just a single genetic marker. Just a single genetic marker does NOT give any reliable information about ancestry and relationship to other populations, so it does NOT constitute evidence. It is NO different from Arnaiz-Villena "studies". For example, Arnaiz-Villena too used just a single genetic marker when "calculating" the genetic relationship of Greeks to other populations (in fact, he used the exact same genetic marker as the one used in the paper you gave link to) and arrived at a completely WRONG conclusion about Greeks."

Onur, you're overeacting. Instead of pushing all-caps, can you give me some useful background? I just asked what the status of HLA research on Otzi is. I don't know what a certain Arnaiz-Villena wrote about Greeks and how it is relevant to Fischer et al. 2001 (is HLA-DRB1*1402 marker itself biased?). The article I quoted seems to support what Dienekes wrote: "Who would have thought a few years ago, that Australian aborigines would show ties to Siberia, some prehistoric central-eastern Europeans to modern East Asians, and neither Mesolithic nor Neolithic Europeans any clear ties to modern ones?" The rarity of this HLA marker in Europe also seems to fit this: "It was already clear with the discovery of G2a in France and Central Europe, that this otherwise uncommon present-day haplogroup in Europe was more prominent during the Neolithic, and Ötzi's data point seals the case." http://dienekes.blogspot.com/2011/09/otzi-tyrolean-iceman-belonged-to-y.html

Onur said...

@Dziebel

Look, just a single autosomal genetic locus does not and cannot be used to show anything about ancestry and relationship between populations (this is especially so for HLA loci, which are subject to strong natural selection) and all geneticists and people with some background in genetics know this simple fact very well, so there is nothing to explain. It is completely unscientific and absurd to come to any conclusion or make any inference about Ötzi from just that genetic locus.

German Dziebel said...

@Onur

"It is completely unscientific and absurd to come to any conclusion or make any inference about Ötzi from just that genetic locus."

I didn't come to any conclusions. I just asked. I'm not going to argue with you regarding matters you don't understand. For instance, how can natural selection undermine the fact that Otzi and Amerindians share an HLA marker?

So, what we seem to know about Otzi at this point.

Y-DNA G2a4
mtDNA K1
HLA DRB1*1402
Lactose intolerant

Let's see what the upcoming publication of his whole genome will show.

Onur said...

I didn't come to any conclusions. I just asked. I'm not going to argue with you regarding matters you don't understand. For instance, how can natural selection undermine the fact that Otzi and Amerindians share an HLA marker?

I did not say natural selection undermines the single HLA locus relationship between Ötzi and Amerindians, do not put words in my mouth. What I have been saying is that that HLA locus is just a single autosomal locus and that a single autosomal locus cannot be used to infer genetic relationships between populations as just a single autosomal locus is extremely unreliable in inferring ancestry and population relationships. This is especially so for HLA loci because of the strong natural selection working on them. I gave you the clear examples of Antonio Arnaiz-Villena studies about the extreme unreliability of a single autosomal locus in inferring ancestry and population relationships, just google his name to learn about them.

"the Dude" said...

A guess: As the Jomon of early Japan are closest to the marginalized northern Ainu, as Otzi will be closest to the marginalized northern Saami/Lapp.

DDeden

German Dziebel said...

@Onur

I checked another paper (http://www.ncbi.nlm.nih.gov/pubmed/15361127). It corrected Aranaiz Villena's results by showing that Greeks cluster with other southern Europeans in a DRB1 tree, with Africans standing apart. But it's noteworthy that DRB1*1402 that connects Otzi and Amerindians was not observed among the 29 DRB1 alleles detected in the Macedonian, Greek, Sardinian and other European samples.

Onur said...

Dziebel, as I said, just a single genetic locus cannot be used to infer genetic relationships between populations. Just wait for the publication of Ötzi's whole genome data.

German Dziebel said...

@Onur

"just a single genetic locus cannot be used to infer genetic relationships between populations. "

You're talking to yourself. My advice to you is to study the evidence and not jump to judgments as to what this evidence proves or does not prove. As it stands now, Otzi's HLA profile is closest to Amerindians.

Onur said...

You're talking to yourself. My advice to you is to study the evidence and not jump to judgments as to what this evidence proves or does not prove. As it stands now, Otzi's HLA profile is closest to Amerindians.

No, I am talking to a wall as you still keep misunderstanding/distorting what I say. I have never denied the closeness of Ötzi's DRB1 HLA locus to that of Inuits and Amerindians. What I have been stating all along is that a single locus relationship cannot be used to infer overall genetic relationships. BTW, as that is just a single HLA locus, it also cannot be used to infer the overall HLA profile.