Nah. I think the Anglo-Saxons included other brands of U106, as well as plenty of I1 among their number. There may have been some P312* and U152 (and even a few L21 and other strays) among them, too.
I am working from memory here, so forgive me if I make a mistake, but it seems to me, in comparing Capelli and Busby, that I1 hits its frequency highs in the same parts of Britain that U106 does.
I think it's Capelli I am remembering, anyway.
I didn't mean to imply the Z8 Frisian cluster was the only Anglo-Saxon group, but they were a key diagnostic marker.
I am going somewhere with this. If we have enough Z8 guys we'll see what their TMRCA is and can compare with other groups like U198.
Is there a form of U152 that might be Anglo-Saxon era immigrants into England?
I don't know. I was thinking of the highest U152 frequency in Busby occurring in Kent, but that could have come with a Belgic or other Celtic people.
If Z8 represents the Frisian Cluster, then it probably is a good A-S spotter where it occurs in England. I didn't re-read Ken's old posts, but I seem to remember him saying the Frisian Cluster is common in Denmark, as well. But maybe my memory is failing me on that score.
Of course, that is a problem with sorting Anglo-Saxons from Danish Vikings. Some of them came from some of the same places. Really, they were pretty much the same people separated by a few hundred years. Of course, by the Viking Era, much of the North Sea coast had been taken out of the old pagan Germanic/Scandinavian orbit by virtue of Charlemagne's subjugation of the Saxons and the conversion of much of the western North Sea coastal population to Christianity.