Just something I’ve done to help me get a better grip of the history of the Y chromosome’s presence in North Africa. Firstly, I need the J tree and it’s distribution from Cruciani 2004.
And some more detailed information on the distribution in the places relevant. Most important to this are J-m267 /J1, (typical of Arabs and common in East Africa) and J-m172/ J2, (which maps the expansion of the Neolithic into Europe and apparently into Pakistan (J2e) and North Africa).
J1 is typically seen as the marker for the Arab tribes expanding into North Africa, and this accounts for somewhat more than half of the J in North Africa. However, the J1 in East Africa is lacking a alteration in the historical-Arab specific Y chromosomes, and the latest paper I have seen dates the entry of this to Africa at the Iberomaurusian-Capsian- (pre neolithic) transition-or possibly a little later- which would require an entry date about of about 12k ago.
Cruciani’s Bedouin sample was free of J2 - as you can see from the maps there seems to be a break in it’s distribution pattern. A look at Italy and Greece (looking for other possible source of J possibly from the Romans and Greeks) showed it at levels low enough that for the Greek and Romans to have made any impact on the J Y chr of North Africa they would had to have left way more European specific haplotypes (the highest J observed in Italy is 29%, overall it’s a lot lower) and the same is true for other middle Eastern countries- to have added any extra J2 into North Africa a lot of other non-J Y chromosomes would have to have accompanied it. The North African Y chromosomes (Lower Egypt as the prime example) just aren’t that varied and mainly show ‘ancient in Africa’ Eurasian and African specific Y chromosomes, with J making up most of the difference, which makes Europe and the recent near East as a source for the J2 unlikely.
The distribution of J2 and J1 in North and East Africa, and whatever near Arabian populations I can find.
From Cruciani 2004
From Luis 2004 in Lower Egypt and Oman.
- Egyptian Arabs… J1 20% J2 12%
- Oman Arabs….. J1 38% J2 10%
From Lucotte 2003
- Lower Egypt…. J1 10.5% J2 8.6%
- Upper Egypt…. J1 3% J2 4.5%
From Arredi 2004
- Lower Egypt… J1 9%, J2 9%
- Upper Egypt J1 21% J2 3.5%
I’m omitting the other studies I have on file as they don’t differentiate between the two, or lack clarity on which is which.
As the other studies are either a bit vague or very small I stick to these. The average amount of J for lower Egypt seems to be 25% (average of 5 studies) with about 10% being J2. Bearing in mind about 10% of the North African J1` is pre Neolithic, about 13.5% of the Egyptian Y chr are ‘Arab’ J1-possibly. J2 from the recent Arab expansion into North Africa probably does contribute to the J2 in NE Africa, but not in the main. The argument against this is that J2 is a minority in the Palestinian Arabs and Bedoiuns , and that to get J2 up to the levels you find in Egypt you’d need to have a lot more J1 and other Eurasian male ancestry- which would make the other African/ancient EurAfrican types way less more common. J2 is also common in Persia (who also invaded Egypt), but again it isn’t dominant and you would have to expect large amounts of other Y chromosomes to have accompanied it, which has not been observed (same argument against a European origin for Egyptian J2).
If the J2 had come in with the Arabs you’d expect a very obvious overweight of J1 in the ratio-as in the Sudan. It’s not even clear if the J1 there is all ‘Arab’ in origin, as the most of the J1 in East Africa is the pre Arabic J1- which makes Hassan’s 2008 choice of description as ‘Arabic’ for all the J1 in the Sudan a little confusing. As Cruciani wrote..
According to this interpretation, the first migration, probably in Neolithic times, brought J-M267 to Ethiopia
Although, I have to say; Hassan’s calling the Sudan Copts a living record of the Egyptians is strange considering how low they were on African Y chromosomes- particularly the Egyptian m78; and that 13 of 33 samples were J1.
While large scale historic movement of Arabic tribes into the Sudan is well documented, a lot of J1 is showing up in groups like the Nubians. When you bear in mind Arab culture is very patriarchal, I can’t understand how the non-Arab groups in the Sudan seem to have about the same amount of J1 as the Arab tribes in the Hassan study. Did more Arabs move into the Sudan than North Africa or is the recent and ancient J1 just getting lumped together in these studies?
I’m sure I’ll add to this post after my regulars have corrected/added whatever info they feel is necessary, but I think mainly but not entirely the J2 in North East Africa is a result of the Neolithic expansion, as it does seem to form a neat radial pattern from Turkey/Iran which is seems to track along with the R1b/p25, which also seems to be Turkish/Iranian.