Dispersal patterns of M267-derived Y chromosomes in the Mediterranean

Unfortunately I can’t access the entirity of this yet.

Dispersal patterns of M267-derived Y chromosomes in the Mediterranean
XVII Congresso Degli Antropologi Italiani

Sergio Tofanelli (1), Gianmarco Ferri (2), Laura Caciagli (1), Luca Taglioli (1), Donata Luiselli (3), Giorgio Paoli (1), Cristian Capelli (4)

Human Y chromosomes belonging to haplogroup J1 (International Society of Genetic Genealogy 2007) share a derived state (G) at the M267 mutation site. It has been argued (Semino et al., 2004) that this mutation originated some 24,000 years ago in the Near East or North-East Africa and spread in the Mediterranean by means of at least two temporally distinct migrations: the first would have occurred towards Aegean and Italian coasts in Neolithic times; a more recent one (estimated time bounds 8.7–4.3 Ky) would have diffuse M267-G in Northern Africa. According to other authors (Nebel et al., 2001; Al-Zahery et al., 2003; Di Giacomo et al., 2004), however, M267-G would have arisen as early as 10,000 years ago and would mark the historical expansion of Arabian tribes in the northern Levant and southern Africa.

We investigated the variability of M267-G chromosomes from 23 different Mediterranean populations (original and published data) at a total of 20 Y STR loci. Three different sets of markers were considered: the “Y-filer” set (DYS456, DYS389I, DYS390, DYS389II, DYS458, DYS19, DYS385a, DYS385b, DYS393, DYS391, DYS439, DYS635, YGATA-H4, DYS437, DYS392, DYS438, DYS448) allowed to more accurately reconstruct time and space of the main dispersal events associated with this mutation; the “MH” (DYS19, DYS388, DYS390, DYS391, DYS392, DYS393) and the “DL3” (DYS388, YCAIIa, YCAIIb) sets allowed the origin and diffusion of local modal haplotypes to be better defined.

The results depict a more complex and deeper stratification of haplotype-clades than thought before. In fact, we could observe both, geographically structured and even lineages, that could be associated to pre-agricultural, Neolithic and historical demographic events.

Results and Discussion

It has been argued that J1s originated some 24,000 years ago in the Fertile Crescent and spread by means of at least two temporally distinct migratory events: the first migration would have bring M267*G to Ethiopia and Europe in Neolithic times [2,11]; a more recent one (estimated time bounds 8.7–4.3 Ky) would have diffuse a J1 subclade, defined by the YCAII*22-22 haplotype, in the southern part of the Middle East and in northern Africa [2]. According to other authors [1,3,11], however, M267 would have arisen as early as 10,000 years ago and would contain genetic signatures (the Galilee and the Palestinian MH [4]) of the historical expansion of Arabian tribes in the southern Levant and northern Africa.

Our results give a substantial increment in terms of geographic coverage and evolutionary resolution with respect to previous analyses (60 haplotypes at 8 YSTR loci [2]), thus allowing a more accurate reconstruction of the demographic events associated with this mutation. The updated dispersal range of present-day M-267*G chromosomes embraces all Mediterranean countries other than vast areas of Eurasia, the Arabian peninsula and eastern Africa, with frequency peaks reaching over 60% in northern Caucasus, Sudan, Maghrib, and the Middle East (Figure 1).

Frequency was inversely correlated to haplotype diversity (MH dbase) because populations from southern Italy, Iberia and Anatolia, where J1 lineage is at low frequency, showed the highest values at mean number of pairwise differences (Figure 2) and Nei’s I (data not shown). The shape of mismatch distributions was ragged for European and Jewish populations, indicating a constant deme size over a long period, whereas unimodal profiles, suggesting a recent rapid growth, were observed in Islamic populations from northern Africa and the Levant.

Complementary demographic inferences were obtained for M172 chromosomes as mismatch analyses gave unimodal profiles on the European shores and in Anatolia and ragged distributions on the African shores. The fact that J2 bell-shaped curves showed lower mean inter-allele differences than J1 ones suggest that J1 chromosomes have undergone population expansions earlier than J2s. Hence, M267 and M172 sites describe phylogenies that experienced different demographic dynamics in time and space.

Other factors than a demographic expansion could arrange haplotype variability into a bell-shaped distribution of pairwise differences: a single localized size expansion could hinder a stationary state at a wider geographic scale or more ancient events; the adhesion to site-finite mutation models could underestimate the time of divergence between STR haplotypes. In order to indirectly verify the occurrence of the above sources of error we performed a mismatch analysis at the Y-filer set on the two largest population samples: Central Italy and Northern Africa (Figure 3).

Again, MD profiles strongly differed on the two Mediterranean sides with a smooth unimodal curve for African haplotypes and a stretched multi-peak profile for Italian haplotypes.

A confirm of the occurrence of a true population expansion would be the presence of star-like patterns within median networks of STR haplotypes. The median-joining network constructed from the haplotypes of the Y-filer dbase is shown in Figure 4. Two star-like conformations can be recognised: a inner one (Exp 1) involving Sudanese haplotypes, one of which exactly matching with one Algerian haplotype; a second one involving Sudanese, Algerian and Tunisian haplotypes (Exp 2).

There are two possible time frames in the history of Mediterranean peopling where to place this putative episodes of expansion: one is the spread of Islam since the VII century AD, one is the diffusion of Ibero-Maurusian and Capsian Mesolithic cultures (15-5 Kybp).

Estimated divergence times for the Exp 2 event (Trho=9.1 Kybp, 95% CI: 7.6-10.6; TASD=9.1 Kybp, 95% CI: 4.8-13.4) exclude a historical expansion and are in good agreement with archaeological evidence of the Ibero-Maurusian/Capsian transition (9-10 Kybp [12,13]).

I’ve long thought that the Capsian in North Africa came from the near East, supported by the Taforalt DNA study. I’d say that the early Ibero-Maurussian was unlikely as the population direction was pretty radial from upper Egypt so I can’t see it spreading  J1 from the near East. Although technically Taforalt is IM in nature, I believe this is the era when new immigrants from the East began to arrive, which is why I lump it in with the Upper Capsian.The frequency hot spot for J1s een in another studies seem to be in the Jordon area. North East Africa seems a bit unlikely, from what I’ve dug up on population movements in that area

What could have caused a population expansion from the near East at this time. I think pre Neolithic pulse farmers, personally. They start to expand from Anatolia into the Med 13,500 years ago. This would make a pre Capsian arrival possible, and would expain why other Eurasian mtDNA  like H/V etc are in Taforalt but don’t show the same time depth as U amd M1. Also, if J1 was in North Africa along with the IM culture, I’d expect it to have some unique derived J1’s in Iberia.


6 responses to “Dispersal patterns of M267-derived Y chromosomes in the Mediterranean

  1. I think pre Neolithic pulse farmers

    What does “pre-Neolithic farmers” mean? Farmers are by defintion Neolithic (or post-Neolithc).

    J1 may have been involved in Neolthic migrations that also affected North Africa but that are poorly understood in that area. And I would not discard either an Egyptian-mediated arrival within Capsian.

    I’d say that the early Ibero-Maurussian was unlikely as the population direction was pretty radial from upper Egypt so I can’t see it spreading

    Iberomaurusian (Oranian) or Capsian? The origins of Oranian are still unclear and the more I look at it the more solid an Iberian origin appears to me (both on archaeological and genetic logic). This wave would have reached the Nile, where European-like rock art is as clear as it is in Anaolia (in both cases more recent than in Europe), and then (Capsian) pushed back west, remixing the genetics and bringing Afroasiatic language.

    Also, if J1 was in North Africa along with the IM culture, I’d expect it to have some unique derived J1’s in Iberia.

    If you think that Oranian (IM) has nothing to do with Iberia, why? It’s pretty clear that there is no cultural or demic movements from North Africa towards Iberia prior to Neolithic. Only the opposite can be true in Paleolithic.

    • There’s a couple of mt DNA hgs that suggest a move from North Africa into Iberia about 20k ago..

      Generally the Neolithic is a date given as starting about 9k ago when the expansion started. i suspect that smaller scale pulse and nut cultivation was happening before this.

  2. You must mean U6. But as Maca-Meyer admits U6 is much more diverse in Iberia than anywhere else, with several high tier sublcades only existing here or, sometimes, in Morocco too.

    I have my own theory on U6 (based largely on Maca-Meyer’s data but not on her conclusions) that reads that U6 is one of those very ancient U-derived founder-effect lineages (like even rarer U8a or more common U5) that must date to Aurignacian (or at most Gravettian) times.

    As I try to correlate arcaheology and archaeo-genetics and not to treat them in isolation as too many do, with inconsistent results normally, and as I just do not trust the MC datations at all (mere erudite guesses at the state of the art at least), I see the following:

    1. Archaeology: strong possibility that Oranian is derived from the original Gravetto-Solutrean of southern Iberia (bothe Gravettian and Solutrean are of European origin, that’s fairly clear). North African Cro-Magnon type also fits best with a European origin (and it must be mentioned that the only place where this type is reported in post-Gravettian contexts is precisely In southern Iberian “Solutrean”, of very marked Gravettian substrate).

    2. Genetics:

    2a. mtDNA U6 appears original from Iberia, while derived U6a (but only this clade) would rather appear original from the Nile (Caspian counter-tide)

    2b. Other typically European mtDNA are also present in North Africa at rather high frequencies (H and V specially but K, a U8 subclade, could also be of European origin)

    2c. Typical European Y-DNA R1b is present at relatively high frequencies at the Nile (Sudan, Egypt also), as well as to some extent in NW Africa, where it may have arived about that time (Euro-like rock art and all that, still to be researched in depth).

    While I guess my position in this matter might appear to some as “Eurocentric”, I find the geneneral bias, specially in regard to Gravettian-derived cultures is kind of “Europhobic” so to say. Whatever the origins of Gravettian, we know that this culture shows a core in Central Europe, western and eastern branches occupying for the first time all Europe south of the ice sheet and derived cultures in North Africa and West Asia. In the context of West Eurasia, Europe (as big as the rest, if not larger) cannot be treated always as periphery and in the particular case of Gravettian and derived cultures it appears to have been the center in fact. In other cases it may not be the case, of course.

    Gravettian and derivatives may have been a major element in keeping West Eurasians a single quite homogeneous population. The ultimate origins of West Eurasians are without doubt in West Asia, and this region, as well as North Africa, may have fed further waves, specially in the Neolithic but it’s not just like everything always necessarily must come from the east. The opposite is not just possible but actually likely in some processes, specially the Gravettian and Gravetto-Solutrean case.

  3. Excellent site mathildasanthropologyblog.wordpress.com and I am really pleased to see you have what I am actually looking for here: this .. as it’s taken me literally 2 hours and 08 minutes of searching the web to find you (just kidding!) so I shall be pleased to become a regular visitor 🙂

  4. J (Y-DNA) itself more than likely originated in East Africa

    J originated in Sudan

    J1 moved South into Ethiopia then Yemen, While
    J2 spread North into Egypt then the Levant

    J1 were African Nomads similar to the Beja & Nubians
    J2 were African farmers connected to the Nile early farmers (Fallaheen culture)

    Areas like Socotra (in Yemen but actually an island in Africa) still have the highest % of
    J* 70%+

    Ofcourse Near Eastern populations will reject this & favor any other origin aslong as its Non-African due to the stigma attached to being of African origin (European influence)

    • Mmmm.

      No. Since every DNA study of J has it as near Eastern in origin. If you applied this to ‘J is African’ theory to Egyptians it would give them effectively zero Arab male ancestry.

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