\'The myth of Celtic and Roman Britain\'

[authun]

Agree modern genetic distribution can be pretty far removed from ancient ones.
Has anyone done studies with DNA samples from burial sites? Even 17th or 18th century graves should be more true to ancient distribution than 20th and 21st century distributions.

Yes there are an increasing number of studies available. In particular, the danish researcher Linea Melchior is widely published on ancient mtDNA studies. YDNA degrades at a much faster rate than mtDNA so the state of research into paternal lineages is really only at the level where researchers are congratulated for having recovered enough yDNA to analyse at all. We have only therefore a small scatter of ancient yDNA results. The techniques of recovering mtDNA on the otherhand have developed to the point where undertaking proper population studies is feasible, with some surprising results.

For example, the frequency of the mtDNA haplogroup I amongst southern Scandinavians is approx. 13% between the iron age and the medieval age but only 2% amongst modern southern Scandinavians. Here we have a good example of a dichotemy between ancient and modern populations. Moreover, the high incidence of Hg I between the iron age and medieval age is not observed in ancient population samples from Italy, Spain, Great Britain, central European hunter-gatherers, early central European farmers and Neolithic samples where it is typically 1.6%. The inference is that high frequencies of Hg I existed in southern Scandinavia before the iron age in contrast to many other parts of europe where it was quite low. Why the frequency drops down to levels typical of more ancient times is not because modern southern scandinavians are representative of other ancient european populations but because of some other event or events.

Several population studies investigate the effect of dilution of Hg frequencies when one population joins another and the consequent effects of one part of the population being more successful than the other. Obviously if one population that has say, 50% of a particular haplogoup, is joined by another population of equal size but has no incidence of that haplogroup, the haplogroup frequency in the new larger group drops down to 25%.If the immigrant group is more successful in the new enlarged group, that particular Hg will drop in frequency even further.

Malmström's paper, 'Ancient DNA reveals lack of continuity between neolithic hunter-gatherers and contemporary Scandinavians.' concluded "Our findings support hypotheses arising from archaeological analyses that propose a Neolithic or post-Neolithic population replacement in Scandinavia". More recently, Melchior's paper 'Genetic Diversity among Ancient Nordic Populations' refines Malmström's finding to the post neolithic and concludes "Our study therefore would point to the Early Iron Age and not the Neolithic Funnel Beaker Culture as suggested by Malmström et al. (2009) [14], as the time period when the mtDNA haplogroup frequency pattern, which is characteristic to the presently living population of Southern Scandinavia, emerged and remained by and large unaltered by the subsequent effects of genetic drift."

In other words, the data is consistent with a group of people entering southern Scandinavia, specifically Denmark, at some time around the early iron age, diluting the genepool. being more successful than the host population and becoming representative of the modern southern scandinavian and north germanic genepools. It is also interesting to note that this is at the same time linguists start the emergence of the germanic language group. Note however, we don't know who these people were or where they came from, simply that they arrived and were successful.

The point is that the ancient southern scandinavian population look different from other parts of europe as far as mtDNA Hg I is concerned, whereas the modern population looks like other ancient european populations. This is not because the modern population is a refelection of other ancient european groups but because it has been influenced by later migrations, the effect of which, has been to make it appear similar to other ancient groups.

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authun