Here is some more food for thought. Jean M has lot more detail but I'm just overlaying the best I can R-U106 and R-P312 aging. Looking at it from a R-L11 perspective, the closest immediate ancestor to both, may hold the key.
-- L23 - 5475+/-680
-- L51 - 5850+/-860
-- U106 - 4175+/-430
-- P312 - 3950+/-400
-- U152 - 4125+/-450
-- L21 - 3600+/-370
I guess I need to understand interclade variance better, rather than intraclade variance. Tim J has taken Ken N's latest version of interclade variance calculations and put them into an easier to use spreadsheet, but Tim still thinks the TMRCA's still add up like Anatole's.
Tim redid his TMRCA's and here is his latest perspective from another forum's posting yesterday.
L11 is a key clade as it is where both U106 and P312 fall and it dominates Western Europe. Using the Myres* data, L11 makes up 95% of all R-M343(R1b) in Western Europe
Tim J's TMRCA estimate for L11 is essentially 3750 BC
, give or take 1500 years. He is using Ken N's intra-clade techniques so I think this is as good as we can get.
Here is a relative aging given by Myres for all of U106
for the oldest locations.
and below for all of P312
Estonia is the only Baltic state that Myres seems to have surveyed but these small states are just to the northeast of Poland. The path from the Polish/Baltic peak age of U106 and the peak for P312 in Anatolia(Turkey) crosses through areas that are considered by some to be the homeland of the Proto-Indo European language (PIE)
David Anthony, author of the "The Horse..." ** contends the Proto-Indo European langaguage (PIE) was spoken from 4000-2500 BC by the peoples in the steppes between the Carpathian and Ural Mountains just north of the Black and Caspian Seas. This overlays the Yamnaya (aka Pit Grave) Horizon or collection of cultures.
Related to the Germanic and Italo-Celtic split, here is what I gleaned from his book.
"It is probably safe to assume that the separations of several western Indo-European branches [Italic, Celtic and Germanic] were associated somehow with these"... three "archeological cross-culture contact areas" between the Yamnaya and to the west from "about 3100 to 2600 BC," during the Early Bronze Age.
1) About 3100-2800 BC, there was "Close integration" with the steppe Usatovo culture (of the lower Danube) and the late Tripolye villages of the upper Dniester and Prut Valleys. There was clear military dominance of the Usatovo steppe peoples over the upland farmers... Anthony believes the Usatov culture was mix of the Yamnaya and Tripolye and believes the Pre-Germanic languages started with them.
2) "True folk migration" of Yamnaya horizon peoples in significant numbers into the lower Danube valley (Romania) and the Carpathian Basin (Hungary) and another branch south into Bulgaria. There was a "massive sustained flow of outsiders into a previously settled land". There was some integration with the Corsofeni culture. The Yamnaya in "eastern Hungary" occupied by "larger population of immigrants" "This regional group could have spawned both pre-Italic and pre-Celtic. Bell beaker sites of the Csepel type around Budapest, west of the Yamnaya settelment region are dated about 2800-2600 BC. They could have been a bridge between Yamnaya on their east and Austria/Southern Germany to their west, through which Yamnaya dialects spreads from Hungary into Austria and Bavaria, where they later developed into Proto-Celtic. Pre-Italic could have developed among the dialects that remained in Hungary, ultimately spreading into Italy through the Urnfield and Villanovan cultures."
3) About 2800-2600 BCE "Yamnaya expanded toward the border with the Corded Ware horizon on the Dniester in far northwestern Ukraine." "This meeting was another opportunity for language shift and it is possible that the Pre-Germanic dialects either originated here or were enriched by this additional contact.
Note that Anthony emphasized the Italo-Celtic branch involves "true folk migrations" whereas the Germanic branch involved "close integration". As it turns out Germanic cultures have a strong mix of Hg I people to go with R-U106 and some R1a. Where the Celtic cultures were heaviest, frequencies of R-P312 are quite high, seemingly meaning the Celtic cultures were less mixed, Y DNA wise.
It is interesting, as Jean M has noted, that the Maykop Culture is one of the earliest for metal working
and it was in the Caucasus on the southern edge of the Yamnaya's.
Also, it is interesting that if you follow Hawks' "Neolithic Milk Fog" blog logic on including the people of Pakistan/NW India with the same milk drinking gene into the analysis, you'd move the Zeder/Berger's (Speigel article) lactose tolerance core region to the east of Hungary right into these same steppes and just about over the Black Sea.
* "A major Y-chromosome haplogroup R1b Holocene era founder effect in Central and Western Europe" - 2010. I used Sweden, Denmark, Germany, Austria, N. Italy AND everything west of these countries as Western Europe.
** "The Horse the Wheel and Language: How Bronze-Age Riders from the Eurasian Steppes shaped the Modern World" - 2007 by David Anthony