DNA’s power to illuminate humanity’s past never ceases to amaze. Collected from those now alive, it shows how their ancestors spread across the world from their African homeland—and, having done so, re-spread in the events known to history as “migrations” and “conquests”.
DNA from long-dead individuals is equally informative. This demonstrates evolution’s byways (early Europeans, for example, retained the dark skin of their African ancestors), and also how Homo sapiens interbred with other human species, now extinct, on its journey to dominion over pine and palm. Now, as an audience at the American Association for the Advancement of Science meeting learned from Maïté Rivollat of Bordeaux University, in France, it can be used to disentangle the family dynamics of previous ages.
Dr Rivollat spoke of her own work in Gurgy, a village in central France, and also of around half a dozen other studies carried out over the past decade. When research of this sort began, it was limited to tracking membership of matrilines (via the DNA of intracellular structures called mitochondria, which pass to a mother’s offspring from her eggs) and patrilines (via Y-chromosomes, which pass intact from father to son). The subject really took off, though, when DNA sequencing became powerful and cheap enough to allow intergenerational tracking of the blocks of chromosomes that swap around when sex cells form. This allows both parents of an individual to be identified, and so permits genealogies to be determined in detail.
One early study was of a mass grave from 2800BC, in Koszyce, Poland, containing 15 individuals. DNA examination showed that these people, who had all been killed by blows to the head, belonged to the same family. The suspicion is that they were victims of a raid. But their burial together suggests at least some survivors were emotionally attached to them.
On the wider question of genealogy, studies of several early sites—the Lech Valley in Germany (occupied from 2500-1800BC), Hazelton North in Britain (occupied in 3700BC) and Dr Rivollat’s own at Gurgy (occupied in 4700BC)—paint a patriarchal picture. Relying on 26 skeletons, the Lech Valley project revealed six multigenerational family units (known to archaeologists as pedigrees), represented by up to eight individuals over as many as five generations. It was clear from their DNA that the women contributing to these pedigrees were outsiders. In some cases they had travelled around 350km to be there.
Hazelton North, meanwhile, showed evidence of polygyny, as well as of incoming women. The 27 skeletons found here were distributed among four burial chambers, each containing descendants of the union of a particular man and one of four women who had, perhaps, formed his harem. And in Gurgy, 63 of the 110 skeletons sampled belonged to a pedigree that stretched over seven generations, again with evidence that the women had their origins elsewhere.
As time passed, things became less patriarchal. Analyses of skeletons from south-west Germany, which date from 600-200BC, suggest women stayed put while men journeyed to marry them. And for Britons brought up on the story of Boudica, queen of the Iceni, a Celtic tribe that rose against the island’s Roman conquerors in 60AD, there is evidence that her contemporaries in another tribe, the Durotriges, were equally feminist. A study spanning the years from 100BC to 100AD showed, via their progeny’s genetics, that many women had several partners.
The most spectacular demonstrations of the new techniques so far, though, are from Hungary and Mongolia. The Hungarian site was a burial ground in Rákóczifalva, in the country’s centre, that was used between 550AD and 800AD by the Avars, a nomadic group from central Asia who had colonised the area. Study of around 300 individuals from this cemetery has yielded a veritable clan of nine interconnected sub-pedigrees, the largest involving 146 people and spanning nine generations.
The Mongolian site, co-incidentally in the part of the world from which the Avars are believed to originate, dates from 2900BC. It accommodates a woman whose ancestry, with five degrees of separation, can be traced to a location 1,400km west-north-west, in what is now Russia.
One thing these studies have in common is that all were conducted in Eurasia (and almost all in the far-western part of this continent, the bit known familiarly as “Europe”). That is hardly surprising. This part of the world is home to vast numbers of archaeologists and paleoanthropologists, and includes the world’s leading centre for the study of ancient human DNA, the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. But researchers are now casting their nets wider, especially in Central America. Stay tuned for revelations about Mayan family life. ■
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