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.