Appearence and tactics of early 5th century Saxons.

[Chariovalda]

I1a marker is found in larger percentages in some regions of France, like Normandy or, more tellingly, in similar percentages in Southern France (Rootsi et al, AJHM 2004)

That is why I - and others - would be reluctant to accept this single haplogroup as evidence for or against for immigration from either a more northerly (North Germany / Low Countries / Southern Scandinavia) or a more southerly (Southern France) location. The sheer fact of a substantial presence of I1a isn't very informative by itself.

To sum up, if we consider the I1a marker as a Saxon, or Germanic marker, we have to admit that the Germanic influence in East England is similar to that of Northern France, or even lower, that would support the idea of a limited migration, not that of a mass replacement of population, unless we think of such massive Frankish migration in Northern France.

Rootsi & co think that I1a originated in France, and "migrated" north after the last Ice Age. That leads to the interesting conclusion that a man with I1a in France might either be descended from a true "native" - or a Frankish immigrant whose distant ancestor emigrated from the same region. That makes the whole genetic history thing in Europe so interesting and confused - migrations, back migrations, back-back migrations )

However, there is another marker probably more important, Haplogroup J is present in almost all Europe, with a clear geographic distribution, with maximum in the Southern Balkans and decreasing to the West. It is widely regarded as a Neolithic population spreading from the Near East through the Danube basin. However haplogroup J is virtually absent in all Britain, that means not only that there was no Neolithic colonization from that group, that also means that, as Haplogroup J is present in relevant percentages (around 10%) both in Western Germany and France, and even in Norway in smaller quantities, no mass migration from those populations arrived to England in postneolithic times.

Do you perhaps have some links? I was aware of J being identified as a possible "Middle Eastern Neolithic Farmer" marker, but two sources I found, [url:vewdobp4]http://hpgl.stanford.edu/publications/AJHG_2004_v74_p1023-1034.pdf[/url] and [url:vewdobp4]http://www.familytreedna.com/pdf/HaploJ.pdf[/url] find respectively 0% J in the Dutch sample and 5% in a (sadly not regionally differentiated) UK sample.
I know J is present in both Dutch, Scandinavian and British populations, but in all cases in relatively low percentages, meaning that, depending on the size (and thus representativity) of the sample, the actual percentage can easily be under- or over-represented. And never mind regional differences...

[size=75:vewdobp4]Edited the links [/size]