The Official "I2 LGM refugium of origin" poll -- Let the debate begin !

[LeBrok]

Right, so probably more important is in what refugium they survived or what refugium was first to repopulated Europe again.

 

[Maciamo]

Right, so probably more important is in what refugium they survived or what refugium was first to repopulated Europe again.

I am not sure that's the most important question since we have seen from Mesolithic samples like Loschbour and Motala that many I2, and even I2a1a and I2a1b samples belonged to subclades that are now extinct or extremely rare. There were surely dozens if not hundreds of I* and I2 subclades in postglacial Palaeolithic and Mesolithic Europe, but those that survived best to this day were those that were assimilated to Neolithic farmers, and especially to Proto-Indo-European Steppe people. Over 90% of I2 in Slavic countries today belong to the I2a1b-L147.2 (aka CTS10228, CTS2180 or Y3111) subclade, which is thought to have arisen 5,600 years ago, just before the Yamna period. These lucky few I2a1b-L147.2 became assimilated benefited from the PIE expansion, and much mater from the Slavic expansion, which saw an explosion of that lineage, especially in the Balkans and the Dinaric Alps. That's why people who just look at the modern distribution map can easily believe that I2a1b originated in and re-exapnded from the Balkans, but that is not the case.

It's easier to understand what happened in post-LGM Europe when looking at the rarer I2c. I2c1 seems to have been in central Europe, while I2c2 would have been around the Black Sea, including in Anatolia and the Caucasus. The two branches have kept very different geographic distributions ever since.

 

[LeBrok]

I am not sure that's the most important question since we have seen from Mesolithic samples like Loschbour and Motala that many I2, and even I2a1a and I2a1b samples belonged to subclades that are now extinct or extremely rare. There were surely dozens if not hundreds of I* and I2 subclades in postglacial Palaeolithic and Mesolithic Europe, but those that survived best to this day were those that were assimilated to Neolithic farmers, and especially to Proto-Indo-European Steppe people. Over 90% of I2 in Slavic countries today belong to the I2a1b-L147.2 (aka CTS10228, CTS2180 or Y3111) subclade, which is thought to have arisen 5,600 years ago, just before the Yamna period. These lucky few I2a1b-L147.2 became assimilated benefited from the PIE expansion, and much mater from the Slavic expansion, which saw an explosion of that lineage, especially in the Balkans and the Dinaric Alps. That's why people who just look at the modern distribution map can easily believe that I2a1b originated in and re-exapnded from the Balkans, but that is not the case.

It's easier to understand what happened in post-LGM Europe when looking at the rarer I2c. I2c1 seems to have been in central Europe, while I2c2 would have been around the Black Sea, including in Anatolia and the Caucasus. The two branches have kept very different geographic distributions ever since.

No doubt about this. Success of many HGs haplogroups depended on "hitchhiking a ride" with farming societies. However the question at hand is about one time frame. Were where I2 in general, or in specific clades, during LGM.
I never voted in this pole though. I think there were few refuge places, which helped bottlenecking, selection and founder affected lucky surviving subclades.

 

[Maciamo]

No doubt about this. Success of many HGs haplogroups depended on "hitchhiking a ride" with farming societies. However the question at hand is about one time frame. Were where I2 in general, or in specific clades, during LGM.
I never voted in this pole though. I think there were few refuge places, which helped bottlenecking, selection and founder affected lucky surviving subclades.

If the question only concerns I2, then the answer is in all LGM refugia. Even north of the Black Sea considering that I2a2a-L699 was found in Yamna, and in the North Caucasus, considering the presence of I2c2 in that region today (but not in Europe proper).

BTW, haplogroup I2's TMRCA is about 21,500 years, which fits right within the LGM (c. 26,500 to 20,000 ybp). Both I2a and I2c were formed around 21,500 years ago too, and top subclades of I2a like I2a1a-CTS595, I2a1b-M423 and I2a2-M436 all existed before the end of the LGM. The post-LGM re-expansion coincides with the appearance of deeper I2a subclades like I2a2a1-M26, I2a1b1-L161.1, I2a2a-M223, I2a2b-L38, etc. Therefore it would be more useful to try to determine from where each of these subclades re-expanded. But it is not that easy as even those top clades were probably very scattered all over the continent. How else to explain that I2a2a-M223 showed up in Early Neolithic Spain and in Yamna? There must have been M223 tribes at least in the Franco-Cantabrian refugium and the Black Sea refugium.

In summary:

- I2a1a-CTS595 would have been present at least in the Franco-Cantabrian refugium
- I2a1b-M423 would have been present in the Franco-Cantabrian refugium, and perhaps also in the Balkans or Black Sea refugia.
- I2a2-M436 and I2a2a-M223 would have been present at least in the Franco-Cantabrian refugium and the Black Sea refugium.
- I2c would have been present at least in the Anatolian and North Caucasus refugia, as well as another on in Europe, possibly Italy.

Not sure where I1 was, but I'd say in the Balkans refugium based on the fact that it was in Hungary when Neolithic farmers arrived. However hunter-gatherers were very mobile, and 12,000 years elapsed from the end of the LGM to the arrival of Neolithic farmers, so it may not mean anything.

 

[LeBrok]

Not sure where I1 was, but I'd say in the Balkans refugium based on the fact that it was in Hungary when Neolithic farmers arrived. However hunter-gatherers were very mobile, and over 14,000 years elapsed from the end of the LGM to the arrival of Neolithic farmers, so it may not mean anything.

Exactly, they could have crisscrossed Europe many times since LGM to Neolithic, and go through many extinctions and expansions. Most likely the Younger Dryas played final and pivotal role for surviving in refugia and final expansion of lucky clades of hunter gatherers. It will be interesting to see one day a snapshot of HGs distribution at year 10,000 BC.

 

[MOESAN]

Y-I2 is old in Europe and I think its ancestors were there before LGM, already among Gravettians, maybe rather between Central Europe and Eastern Europe more than in Western Europe without exclusion nevertheless. So more than a refugium can be supposed. If I had a preference I would say Balkans as a stronghold but without exclusivity. I think it could have been pushed (rather westwards and northwards) and displaced by Neolithic advance before being incorporated into agricultural groups; it's possible I2a1a ancestors arrived lately enough in Sardigna, from East Adriatic shores? the I2a1 of N-E Spain are maybe oldest there.. The Y-I2a1b ancestors I believe stayed for a while in mountainous refugia of Western Balkans and Carpathians; Y-I2a2 ancestors could have been settled more Central or East before recolonization of Northern lands; some could have chozen local mountainous refugia in front of farmers advance before partial assimilation. I have not definitive thoughts in fact; I believe a big part of Y-I2a2 groups - after some time of isolation from Farmers - were involved in proto-historic moves linked to metals on different directions. I'm not sure the today distribution of I2a2 in Northern Europe and the Isles is too old even if someones could have climbed northwards long ago. All guesses as often.

 

[bicicleur 2]

TMRCA of I2 is 22.000 years but it has not been found in paleolithic Europe, it was only found after spread of the Villabruna clade into Europe 14 ka

I guess their refuge was the caves west of Antalya (Carain, Belbaçi, ...) during LGM and they learned about microliths and archery from the Boncuklu people (Konya area)

 

[halfalp]

Pointless ? just one I2c tribe in northcaucasia, can be at the origin of everything that people on eupedia is in search for ( pre-proto-indo-european, maykop signal... ) You are so focusing on gold and let silver in the hole... When R1b is found in pontic-steppe its the ANE signal, when CHG has being theorized, well R1b suddenly came from transcaucasia or iran, blabla... The details is the most important, we found some unusual mtdna haplogroups in maykop, so maybe, we gonna found some unusual y-dna haplogroups too. Like we found for exemple I2c around the caucasus and in Iran, G1 in eurasian steppe, iran, even on mongolia, in modern days. What are their signal ? For what are they match, in case of population mouvement, or cultural horizon ?