Sorry Bertrand, but this scenario that you present is completely impossible. The date of 10,000BC that you give is is far in excess of the generally estimated age of S28 (~3,500 YBP). You also have to consider the general distribution of S28 (France, southern Central Europe, Italy), from which the Bashkirs are a clear outlyer. I do however agree with Maciamo that the Bashkirs in general and the other R1b lineages from the sample excluding S28 are probably old.
Hello, sorry I was on vacation for a week but I would like to resume this thread because I really believe that S28 originated in the Bashkir area and I would like to try another attempt at convincing you:
Regarding the date of S28, most studies recognize that the current dating method for more recent mutations are unreliable (for those younger than 20,000 years old). Therefore the "guestimate" of 3500BC for S28 is not sufficient to discard my hypothesis. In addition, given the large amount of S28 holders today, a recent age is less likely.
If R1b is 25,000 years old (Myres et al.), S28 must be older than 3500 yrs old given the frequency of this marker in Europe today.
I believe the key to this problem is in the book: "the horse the wheel and language" by David Anthony. Anthony shows very convincingly that:
1) The PIE developed around 4000BC in the steppes of Ukraine
2) language similarities show that they came from the southern ural region after the Ice Age
3) They later evolved into two groups: a western group and an eastern group.
The western group emigrated up the Danube and Dniester (late centum languages around 3000BC) and the eastern group (satem) emigrated up the dnieper and back east toward the Ural and India
If now you map genetic maps to these patterns, it comes pretty clearly that Western PIE were mostly R1b and Eastern PIE were mostly R1a (as shown also by ancient DNA of Tarim mummies.) Therefore, at a time where Western PIE went up the Danube to found celtic and Italic civilizations, i believe it is highly unlikely that some of these (S28) went back to the Bashkir area. Only r1a went back up to the Ural via a reverse migration up the Volga.
I believe it is much more likely that S28 appeared before the emergence of the PIE, at the time when this group came down the Volga on its way to Western Ukranian steppes.