Family Tree DNA scientist
Gail Tonneson writes to me on U5b1b1:
U5b1b1 is found throughout Europe and is ancestral to the Saami signature U5b1b1a and the Berber signature U5b1b1b. So the Saami and Berber lines are sister groups to your line with a common maternal ancestor for all U5b1b1 probably around 8,000 years ago. Another way to view this - your maternal lines defines a new branch in the U5b1b1 tree dating to about 8,000 years ago. I'd suggest trying to contact your exact match to see if your maternal ancestors are from the same country or region. It is uncertain how long ago your common maternal ancestor is with your exact match - it could be anytime between a few hundred years to a few thousand years.
(I have one exact full sequence mtDNA match in the Family Tree DNA database.) Taken together with earlier information, 48% of Saami are in U5b1b1, some of them living today are even further defined as belonging to U5b1b1a - a more derived line which is not shared by the Berbers or by anyone else in Europe (which is why it is called the Saami Signature, as it is exclusive to some of the the Saami living today). U5b1b1 is still an ancestral Saami motherline and part of major motherline 1, and not all Saami living today are U5b1b1a. The Saami living today (those of major motherline 1, at least) and I share the same ancestors, though obviously, I don't live in Scandinavia and am not Saami in that sense. My motherline has developed into it's own unique branch which has yet to be exactly defined by geneticists, and which is itself a sister line to some currently living Saami (48%) and Berbers (2%).
Still, my motherline is part of ancestral Saami major motherline 1. My ancient ancestors are the ancient ancestors of today's Saami, whether or not these ancient ancestors were or are called Saami or something else. My meaning when I say "my Saami ancestors" is that my ancient ancestors were the indigenous population of Scandinavia and Europe, the same as many of those Saami living in Scandinavia today. I call them Saami for convenience, since I don't know what they called themselves way back then or what scientists call them today.