are STRs and SNPs failing to pick up the main migration periods of R1b1b2

[alan trowel hands.]

I get the increasing impression that in most cases STR clusters are not currently capable of seeing connections much into the BC period while there is a big gap in the SNPs between the P312/L21/U152/U106 period estimated about 4000 years ago and the much more localised historic period SNPs and clusters.  That means that most of the period between the coming into existence of the P310 clades and the historic period (over 2000 years) cannot currently be 'read'.  All we have is course grain philogeny and variance.  Maybe that sounds unduly negative but it does seem to me that the main migration period of the P310 clades falls into a period where neither SNPs or STRs are throwing much light. 

[MHammers]

I've noticed from looking at L21 on the Yahoo group a few observations.

1- L21 can be broken into 3 groups of similiar size.  The first one is the members identified as L21*(though not all are fully snp tested, they don't have the signature alleles of known downstream subclades).  The second is those who are in a defined str cluster, but still without an snp discovered confirming a true subclade.  The third are the members who are M222+, L226+, L193+, and so on.

2-  In the first 2 groups everyone seems to average anywhere from 18-22 GD from other members in those 2 groups.  I'm not sure what those GD's mean exactly, I'm thinking somewhere in the span of the bronze age, maybe around 1000BC (Urnfield period).  Although L21 may have its origin ultimately in a P312 dominated Beaker timeframe, could most of today's L21 members be a result of a population explosion from a late Bronze age or early Celtic period?  I think the Nordic Bronze age might explain the Scandinavian L21+, due to the Atlantic trading networks and the proximity to Urnfield.

3- The Isles, Colonials, and even some of the Scandinavians cluster closer with each other.  This is not too surprising.  However the French and a few other continentals seem to be the most distant from everyone else including each other.  What I did find interesting is some of the Iberians, the Low Countries, and a few Germans seem to be intermediate between the more distant French group and the Isles/Scandinavians based on average GD's among L21* types.  

4-  The continentals have a larger percentage of L21* members than the Isles further supporting a continental origin.