When did Europeans settle American continent and how old their genes are?
Beside that, you keep quoting Regueiro et al like it is a bible. This forum only, has several members which have much better understanding of history of Y-DNA in Europe, than authors of that document. If you want to get some real knowledge, put that document on a much lower position and find information which is relevant.
We can be conservative and ignore all new researches. We can say science no longer has anything new to say. We can stay in the belief that I2a2 and R1a came to the Balkan 1,500 years ago with Slavs and deny new findings.
But science is progressing. You can see Regueiro et al. (2012) claim about Balkan I2a2 9,000 years ago. And in the debate that I had with Sparkley we reduced for 3x claims these authors. Results is I2a2 in the Balkans is 3,000 years ago. It is much earlier than Slavic expansion.
For R1a things are more apparent. R1a in the Balkans is very very old. You know a lot of authors have claimed, not only Regueiro et al. Probably from all today's haplogroups in the Balkans R1a is the oldest. And Regueiro et al. find only 5,8% R1a-M458 among Serbs, versus older 14,8%.
You can see that R1a is very stable in the Balkans. All Balkan populations have a share R1a, in fairly equal measure. Understandably, Croats and Slovenes have the most (due to the movements of Slavs), but every Balkan population has. R1a came in three big waves in the Balkans, first wave was a long long time ago, estimates of different scientists ranging from 20,000 years to 7,000 years.
Today, who says that R1a came to the Balkans first time with Slavs in the 5th century is similar as to say that atoms are the smallest known particles, that no new elements after Mendeleyev or that planets in Solar systems are the only planets in the Universe. But science has advanced and we know that this is no longer true.
For me it is interesting to find out to which haplogroups belonged the members of old Balkan cultures, for example people who created the culture at Lepen Whirl, eastern Serbia (peak about 7,000 years ago). Skeletons of these people has been saved and probably it is possible to determine haplogroups (I started thread on it).
Also Vincha culture (Serbia, Romania) who had early period (7,500-6,800 years ago) and late period (6,800-6,200 years ago). Researches of this kind will surely be performed and we see results.