Maciamo said:
Good point, but the Pontic-Caspian Steppes were inhabited by R1a HG tribes when R1b cattle herders crossed over the Caucasus. It wasn't virgin land. Therefore it must have taken a few centuries for R1b herders to occupy the large territory that would become Yamna and drive out the indigenous R1a people.
Although this theory is plausible, one of problems is the fact that so far there is no proof that HG tribes in the Pontic-Caspian tribes were R1a. Quite the opposite, the only known HG sample from the steppe - Samara HG - was R1b. Two samples of R1a HGs were found far away from the steppe, but they were xM198, so they are about as irrelevant to the Indo-European question as Chadic-speaking R1b-V88 in Neolithic Iberia. The oldest R1a from the steppe appears in Khvalynsk culture and it autosomally distinct from Mesolithic HGs, it is also autosomally the same as R1b sample from Khvalynsk culture (I'm not sure about autosomal DNA of that 3rd sample which was Q1a and was buried without any grave goods, he was also killed by 4 strikes against his head - perhaps he was an intruder from some hostile tribe, and not part of the community, unlike the other two samples).
Maciamo said:
However since Z283 is so common in Germany and the Scandinavian branch, descended from Corded Ware, is undeniably Z283>Z284, I still stand by my theory that Corded Ware must have possessed Z283. It's also possible that other side lineages were present, including L664 and extinct branches.
Territory occupied by Corded Ware culture was huge, extending from the Rhine to the Volga. Z283 was probably more prevalent in Central and Eastern CW, while xZ645 was probably more numerous in Western CW. Later there took place "in situ" migrations within the former Corded Ware zone, such as Baltic migrations (according to Gimbutas up to the Oder, IIRC) and Slavic migrations (beyond the Elbe). A common Balto-Slavic subclade
R1a1a1b1a2 Z280 appears in Germany for the first time in I0099 / HAL36 Urnfield sample from Halberstadt, dated to 1113-1021 BC.
Maciamo said:
That's also why about 10% of R1b-L23 is found in all Slavic countries today
I think this amount is closer to 5%, at least if we believe N. Myres et al. 2010:
R1b-M269 in Poland according to N. Myres 2010 (n=202):
L51 (= 11,91% of Y-DNA and 64,9% of R1b):
U106(xU198) ------------- 0,0594 (= 5,94%)
U152 ---------------------- 0,0347 (= 3,47%)
S116*(xM529xU152) ---- 0,0101 (= 1,01%)
M529(xM222) ------------ 0,0099 (= 0,99%)
L11*(xU106xS116) ------ 0,005 (= 0,5%)
xL51 (= 6,44% of Y-DNA and 35,1% of R1b):
L23(xM412) -------------- 0,0544 (= 5,44%)
M269(xL23) -------------- 0,005 (= 0,5%)
M412(xL11) -------------- 0,005 (= 0,5%)
M269 all ------------------ 0,1835 (= 18,35%)
And in Germany also according to Myres 2010 (n=321):
L51 (= 42,05% of Y-DNA and 95,8% of R1b):
U106(xU198) ------------- 0,19 (= 19%)
U198 ---------------------- 0,0187 (= 1,87%)
U152 ---------------------- 0,1028 (= 10,28%)
S116*(xM529xU152) ---- 0,0685 (= 6,85%)
M529(xM222) ------------ 0,0187 (= 1,87%)
M222 --------------------- 0,0031 (= 0,31%)
L11*(xU106xS116) ------ 0,0187 (= 1,87%)
xL51 (= 1,83% of Y-DNA and 4,2% of R1b):
L23(xM412) -------------- 0,0062 (= 0,62%)
M269(xL23) -------------- 0,009 (= 0,9%)
M412(xL11) -------------- 0,0031 (= 0,31%)
M269 all ------------------ 0,4388 (= 43,88%)
More data in Supplementary Table S4:
http://www.nature.com/ejhg/journal/v19/n1/suppinfo/ejhg2010146s1.html
Here a graph (made by user Hereward from The Apricity):
http://s21.postimg.org/bb07dljdz/Myres_Graph.png