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 . 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 ) 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 ), 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.