Keep in mind Abramelin that the genetic evidence suggests that pale skin only developed in the area of the Caucasus c.4000 - 10000 BC. So anyone living before that time would of course been dark skinned.
European Skin Turned Pale Only Recently, Gene Suggests
Also that while subgroups of I2a and I2b would have existed in Europe at the time, I2a2b/L-161 appears to only date to c.5370 BP (3370 BC), which is well after the disappearance of Doggerland. As well as mentioning that, contrary to your picture, it's known that the end of Lake Agassiz-Ojibway and Doggerland did NOT happen at the same time but were in fact separate events.
Estimated TMRCAs for Y Haplogroup I Clades
Edited by cormac mac airt, 07 July 2011 - 03:34 PM.