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View Full Version : The when, where and why of the R1a/R1b split



alan
12-20-2013, 04:46 PM
I would be interested in how people envisage the origin of the different paths they took.

As for the when, based on Michal's calculations, I think the following dates seem reasonable:

haplogroup R - c. 30000BC
haplogroup R1 - c. 25000BC
R1b-P25 - c. 20000BC

That would place R1 at the start of the LGM,not the end as previously suggested.

This map shows the conditions that the first R1 man may have faced

http://en.wikipedia.org/wiki/File:Last_glacial_vegetation_map.png

Essentially, other than small refugia not noted on a map of this scale it can be seen there was essentially a choice of living either in southern areas of Europe and Asia or living along the steppe tundra belt that stretch across Eurasia.


Maciamo keeps making statements that this allowed free movement from Altai to the Atlantic but this is not the case. Communication between east and west was enormously impeded and squeezed by the northern ice sheets and polar deserts to the north and the Alpine glaciars to the south. This is borne out by the cultural differences that are marked the LGM with Solutrian developing in the west during a long period of isolation during the LGM (culture probably arose fairly early in the LGM.

So what are the options for R1 to have spread from somewhere like central Asia across Europe.

Clearly the Aurignacian c. 40000BC is not a good candidate as it is far too early for even R*. Prior to the LGM the Gravettian swept Europe a little c. 28000BC. Its origins and direction of spread are still debated. In itself it is a little younger than R* in Michal's calculations. It beat the LGM in its spread across Europe before east and west diverged through separation in the LGM. However, the problem with this is this movement apparently pre-dated the origin date of R1 meaning that if Gravettian crossed Europe with R involved it would have been R*, not R1 and you would have ended up with separated R* populations in the western and eastern refugia, not two separated R1* populations. By the age of R1* the LGM had split Europe into refugia and there was developing separation between the eastern and western European populations. I think its very likely R was on the eastern side of the divide until at least the end of the LGM.

Indeed I am not so sure that R was involved in the Gravettian. The Mal'ta boy was a very late member of the Siberian middle upper palaeolithic culture, a culture which apparently started c. 30000BC with a reoccupation of Siberia. It is not the same as the gravettian culture which started a little later, had a different distribution and different technology. Other than the Mal'ta boy c. 22000BC this culture seems to have declined after 25000BC when the LGM started - pretty well the same date as R1* emerged. The Mal'ra boy seems to have been from a rare family of this dwindling culture who remained during the LGM until its very worst.

IMO it seems likely that R1 emerged among distant cousins of the Mal'ta boy who left south-central Siberia c. 25000BC. However, as the above map of the LGM implies there options for movement were being cut off by the desert band through central Asia and IMO they either had to live on the steppe tundra or move into south Asia. The area in between was not an option. My feeling is that is would have been much more natural to head straight west along the steppe tundra which is essentially the environment they were used to. Depending on exact dates the option of moving to south Asia may not have existed c. 25000BC when R1* arose.

Although I wouldnt rule out a short move south to around Altai, there doesnt seem to be any really upsteam forms of R in that area and if I had to guess I would say they moved along the northernmost edge of central Asia (the southermost edge of the steppe-tundra) until they reached the Caspian. Once at the Caspian its shores and waters would have allowed movement from north to south that was not possible in desert central Asia. during the LGM. Ideally we would want to identify this move from south-central Siberia archaeologically. I am going to dig into this to see if there is any evidence. If not maybe the Altai refuge needs considered again - something interesting given south Altai's potential role in the origin of microblade groups during the LGM and their role in the spread of haplogroup Q to America after the LGM.

alan
12-20-2013, 04:52 PM
In modern terms any journey west by south-central Siberians about 25000BC would seem likely to me leave its traces in south-western Siberia and northern Kazakhstan. I will look into this. Another thought is that superlake in western Siberia- what was human settlement like there?

http://upload.wikimedia.org/wikipedia/commons/e/e4/Last_glacial_vegetation_map.png

vettor
12-20-2013, 05:37 PM
Although I wouldnt rule out a short move south to around Altai, there doesnt seem to be any really upsteam forms of R in that area and if I had to guess I would say they moved along the northernmost edge of central Asia (the southermost edge of the steppe-tundra) until they reached the Caspian. Once at the Caspian its shores and waters would have allowed movement from north to south that was not possible in desert central Asia. during the LGM. Ideally we would want to identify this move from south-central Siberia archaeologically. I am going to dig into this to see if there is any evidence. If not maybe the Altai refuge needs considered again - something interesting given south Altai's potential role in the origin of microblade groups during the LGM and their role in the spread of haplogroup Q to America after the LGM.

The movement of people from areas you noted was due to the volume of water in the areas, the caspian sea and aral seas where virtually one great ocean at least to the late bronze-age. Agriculture was non existence in that area due to the depth of the water . aral sea had 250 metres of water . Movement was forced.

There is an interesting 10 part series ( i think created in 2013) called Alexanders lost worlds ..........it exclusively only deals with lands from east of the caspian sea up to the himalyas/pamir mountains

Joe B
12-20-2013, 08:19 PM
I would be interested in how people envisage the origin of the different paths they took.

As for the when, based on Michal's calculations, I think the following dates seem reasonable:

haplogroup R - c. 30000BC
haplogroup R1 - c. 25000BC
R1b-P25 - c. 20000BC

That would place R1 at the start of the LGM,not the end as previously suggested.

This map shows the conditions that the first R1 man may have faced

http://en.wikipedia.org/wiki/File:Last_glacial_vegetation_map.png

Essentially, other than small refugia not noted on a map of this scale it can be seen there was essentially a choice of living either in southern areas of Europe and Asia or living along the steppe tundra belt that stretch across Eurasia.
What conditions would be required for the R1a/R1b split and where did they flourish separately? My guess would be for refugiums that are seperated by a good distance. Any one of the transverse mountain ranges of Asia such as the Pontic, Alborz or Tian Shan would be good candidates.
The attached Nasa Blue Marble image is from the winter of 2004. It nicely shows where the climate would be really rough and where to find refuge. Summer during the last LGM?
1082
NASA image, not copyrighted (http://www.nasa.gov/audience/formedia/features/MP_Photo_Guidelines.html#.UrS4l_uIq6k)

alan
12-20-2013, 11:34 PM
For me the question is whether, during the LGM, R1 was split geographically into two groups that later led to R1a and b or whether they stuck together. The odds still seem on the latter as the oldest recent date I have seen suggested for R1* is c. 25000BC and I think any later than that and they basically would have been compelled by the LGM desert barrier in central Asia to remain to the north of it.

I am assuming R* was associated with the south central Siberian middle upper palaeolithic culture (which the Mal'ta boy was a very late member of) for the duration of that culture (which arose 30000BC and was disappearing c. 25000-20000BC. Mal'ta boy is often talked about as being a dead end R line which split from the R that led to R1 a good few thousand years before he lived. Well what they do not tend to realise is that Mal'ta boy's culture commenced in the same south central Siberia area about 30000BC around the time that R arose.

So, there is no mystery about Mal'ta boy's roots. The culture he was associated with have long deep roots in the area where he lived and died. I get the impression some people want to try and link him as if he was some sort of outlier individual of a group from further west or even Europe. However, this would not appear to be the case. The culture of Mal'ta boy had been around for perhaps 8000 years in the same general location before the Malta boy was born and had a duration c. 30000-25000BC after which it seems to have really dwindled for a few millennia. The culture occupied this area in what was a period of good climate and dwindled as the LGM took hold. It was not the same as Gravettian and is a little older than the latter culture. So, unless Mal'ta boy was a stray person who moved into another culture (which would be special pleading IMO) then his ancestors lived in south-central Asia for 8000 years before he lived.



What conditions would be required for the R1a/R1b split and where did they flourish separately? My guess would be for refugiums that are seperated by a good distance. Any one of the transverse mountain ranges of Asia such as the Pontic, Alborz or Tian Shan would be good candidates.
The attached Nasa Blue Marble image is from the winter of 2004. It nicely shows where the climate would be really rough and where to find refuge. Summer during the last LGM?
1082
NASA image, not copyrighted (http://www.nasa.gov/audience/formedia/features/MP_Photo_Guidelines.html#.UrS4l_uIq6k)

alan
12-21-2013, 11:42 PM
I suppose in general I tend to go along with the idea that the Aurignaician and Gravettian groups were non-R, the latter probably I. If R1* arose around the time the Mal'ta Siberian culture was starting to decline and heading west then it is possible it joined might have moved into the eastern fringe of Europe perhaps 25000BC. I dont think the archaeological record is good enough to detect a Siberian westwards move west around then if it happened. On the other hand it could have remained around Altai until the end of the LGM. Modern distribution of early and diverse branchings of R1a and b would suggest to me that R1* did head west. However, the question is how far west. I would think getting west of eastern Europe would be unlikely in the LGM. If they simply moved directly west from south-central Siberia c. 25000BC they would have encountered existing Gravetian groups once they approached the Urals and westward. I have been looking about to see if there is a hint in the Russian archaeological record of a move from south central Siberia towards Europe in that time period but I have not found anything useful yet. It is possible that a more southern route may have been taken. I will continue to try digging around for evidence for Siberian refugees moving west as the LGM took off.

alan
12-23-2013, 12:36 AM
I am very interested in the ideas about eastern input into the western steppes as well. Its something that I am not sure about as these ideas seem to rise and fall. The epipalaeolithic and mesolithic periods saw things like microblade technology and pre-farming pottery, ideas that both now are looking like they spread across Asia and into eastern Europe from Altai and east Asia after the LGM. I wonder if its possible that any of this had a genetic signal.

p307 on is particularly interesting in this publication on microblade diffusion

http://books.google.co.uk/books?id=Qjm8IbYgnmAC&pg=PR8&lpg=PR8&dq=diffusion+of+microblade+eurasia&source=bl&ots=YS5hF6wHZA&sig=ZtLDlHvg21gjY7aJ37nLtnysXsA&hl=en&sa=X&ei=BYG3UoLTHu6p7AbI14HwAQ&ved=0CFMQ6AEwBQ#v=onepage&q=diffusion%20of%20microblade%20eurasia&f=false


True it's just important to realize the mixed character of later steppe cultures. There were multiple cultures with input into yamnaya but some people are still arguing for the presence of just one haplogroup. They really shouldn't be taken seriously IMO.

alan
12-23-2013, 07:00 PM
This an interesting paper on the western steppe at the end of the Palaeolithic and early Mesolithic before the more well known Mesolithic and Neolithic groups develop. It touches on possible movements

http://vddb.library.lt/fedora/get/LT-eLABa-0001:J.04~2006~ISSN_1392-5520.N_7.PG_136-148/DS.002.1.01.ARTIC