Central Asian Y chromosomes and the source of migrating humans

Assessing relatedness in the male line from Y chromosome samples of large, widespread populations, is becoming an important tool in palaeoanthropology.  It uniquely shows signs of the major migrations by fully modern humans during the last glacial period and the Holocene (see Eve never met Adam December 2000 Earth Pages News and  Multiregionalists nailed by Y chromosome? June 2001 Earth Pages News).  Although the details make difficult reading for non-geneticists, a recent paper by a large multinational team, led by Spencer Wells, Ruslan Ruzibakiev and Nadira Yuldasheva of Oxford University and the Uzbekistan Academy of Science respectively, sheds important light on where these migrants set out from (Wells, R.S. and 25 others 2002.  The Eurasian heartland: A continental perspective on Y-chromosome diversity.  Proceedings of the National Academy of Science, v. 98, p. 10244-10249).  Central Asian men have among the most diverse genetic make up of any living humans.  Genetic markers on Y chromosomes from that population turn up far afield, so that it seems that the great migrations to Europe, to the Indian sub-continent and even North America set out from the region of Afghanistan, Uzbekistan and Pakistan.

Is evolution predisposed to intelligent beings?

Simon Conway Morris of Cambridge University is one of the younger pioneers of palaeobiology, beginning with his doctoral studies of the famous Cambrian creatures of the Burgess Shale.  His discoveries and analyses of them have clearly set him on course for thoughts of a much broader kind, much as did the career of Stephen Jay Gould.  By way of introduction to his forthcoming book (Life’s Solution: Inevitable Humans in a Lonely Universe, Cambridge University Press, scheduled for 2003) a recent article by him (Conway Morris, S. 2002.  We were meant to be….  New Scientist, 16 November 2002, p. 26-29) will cause a stir.  At first sight it smacks of teleology, the predestination of biological processes to create the thinking mind.  It is far from being teleological, because Conway Morris argues from sound evolutionary principles about the role of fitness.  To him, there is evidence of evolutionary convergence towards smart creatures, such as dolphins and even octopuses and social insects; the outcome of gathering and processing information in some kind of integrated mental map.  Unfortunately, detecting signs of such behaviour in the fossil record is not easy, unless advanced intelligence created recognisable artefacts.  Such evidence spans only the last 2.5 Ma, and of course it originated with hominids, and with them alone; we find few signs of the dolphin’s predilection for using snout guards while grubbing in the seabed – a likely tale!.  What he does not address is the difference between intelligence and the consciousness that turns environments into tools for our species, which in turn drive the generation of culture, economy and a free association of individuals.  Much as we might wish to, we cannot converse with a dolphin, an advanced mollusc or an ant.  Which is a shame, because a really smart cookie needs to work on the principle of, “It takes one to know one”!  All manner of living animals use tools of a rudimentary kind, even the song thrush in my back yard, so Conway Morris is mainly restating a truism.  But that is fine as a starting point for speculation, and what I take to be pure fun.  But as a basis for some optimism that when we meet a truly alien intelligence it should be pretty easy to have a good old natter, is being silly.  If he does hold that view, then I can recommend a few hours in the Aztec exhibition in London; as like as not we would be a menu item for any intelligent being which had crossed a thousand light years out of curiosity or for plunder!  Life’s history on Earth has not been simply one of evolution, but of awesome snuffings out, and many other chance combinations of circumstances outwith any kind of biological necessity.  Being ever so clever is little help against a Chixculub or the Siberian Trap.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s