The Genetic Map of Europe

Genetically speaking, Finns and Italians are the most atypical Europeans. There is a large degree of overlap between other European ethnicities, but not up to the point where they would be indistinguishable from each other. Which means that forensic scientists now can use DNA to predict the region of origin of otherwise unknown persons (provided they are of European heritage).

These are among the conclusions to be drawn from a genetic map of Europe, produced by the Erasmus University Medical Center in Rotterdam (the Netherlands), published in the August 7, 2008 issue of Current Biology. In its Science section, the New York Times devoted an article to the study, reproducing the genetic map.

The discovery that autosomal (i.e. non-gender-related) aspects of DNA may be used to predict regional European provenance of unkown individuals was made by prof. dr. Manfred Kayser’s team of forensic molecular biologists. In a press release, the Erasmus UMC stated that this might potentially be helpful in resolving so-called ‘cold cases’.

The genetic map of Europe was compiled by comparing DNA samples from 23 populations in Europe (pictured on the right-hand side map).Those populations were then placed on the ‘genetic’ map according to their similarity, with the vertical axis denoting differences from south to north, and the horizontal one from west to east. The larger the area assigned to a population, the larger the genetic variation within that population.

When compared to the actual map, the populations kinda sorta maintain their relative position to each other. Two observations spring to mind immediately: the fact that most populations overlap so intimately with their neighbours. And that Finland doesn’t. Some other observations:

The extent of genetic variation is greater north to south than east to west.This may be a result of the way Europe was colonized by modern humans, i.e. from the south, in three successive waves of migration (45,000 years ago, where before there had only been Neanderthals; 17,000 years ago, after the last Ice Age; and 10,000 years ago, with the advent of farming techniques from the Middle East).

The isolation of Finnish genetics can be explained by the fact that they were at one time a very small population, preserving its genetic idiosyncrasies as it expanded.

The relative isolation of Italian genetics is probably due to the Alps, providing a geographic barrier to the free and unhindered flow of population to and from Italy… Although Hannibal, the Celtic and Germanic influence in Italy’s north and of course the expansion of the Roman Empire would seem to contradict this.

Yugoslav genetic variation is quite large (hence the big pink blob), and overlaps with the Greek, Romanian, Hungarian, Czech and even the Italian ones.

There is surprisingly little overlap between the northern and southern German populations, each of which has more in common with their other neighbours (Danish/Dutch/Swedish in the northern case, Austrian/Swiss/French in the other one).

The Polish population is quite eccentric as well, only significantly overlapping with the Czech one (and only minimally with the northern German one).

The Swiss population is entirely subsumed by the French one, similarly, the Irish population almost doesn’t show any characteristics that would distinguish it from the British one.

British and Irish insularity probably explains why so much of their genetic area is not shared with their closest European cousins, i.c. the Norwegian/Danish/Dutch cluster.

Many thanks the many people that sent in this map.

Strange Maps #306

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