MOTHER TONGUE
Newsletter of the Association for the Study of Language In Prehistory

Issue 26 · Spring 1996


Rising Tide Theory Fails Tests

The multi-regional theory of anatomically modern humans & their world distribution has been battling the 'Eve' or 'out-of-Africa' or 'Noah's Ark' theory for about a decade. Based on the premise that Homo erectus was the last global diaspora from Africa and that regional varieties of Homo sapiens arose from regionally-evolved Homo erectus varieties, this theory denied an African diaspora or migration of modern man. One of its key points was that modern crania from China were more like ancient local crania than like modern African or European ones.

Biogenetic work has tended to be critical of multi-regional proposals. A recent nuclear DNA study (from the nuclear autosom-al genome) supports the 'Eve' theory -- or fails to support the rising tide and finds that the diversity in Africa exceeds that in the rest of the world. In this there is no support for east Asian separateness, since the entire mass of Eurasians is more homogeneous than Africa. Thus a blow to multi-regional-ism. (Source: S.A.Tishkoff, et al, SCIENCE, vol.271, 8 March 1996: 1380-87. "Global Patterns of Linkage Disequilibrium at the CD4 locus and Modern Human Origins".) Their abstract says: "Haplotypes consisting of alleles at a short tandem repeat polymorphism (STRP) and an Alu deletion polymorphism at the CD4 locus on chromosome 12 were analyzed in more than 1600 indi-viduals sampled from 42 geogra-phically dispersed populations (13 African, 2 Middle Eastern, 7 European, 9 Asian, 3 Pacific, and 8 Amerindian). Sub-Saharan African populations had more haplotypes and exhibited more variability in frequencies of haplotypes than the Northeast African or non-African popula-tions. The Alu deletion was nearly always associated with a single STRP allele in non-African and Northeast African populations but was associated with a wide range of STRP alleles in the sub-Saharan African populations. This global pattern of haplotype variation and linkage disequilibrium suggests a common and recent African origin for all non-African human populations."

When did this biogenetic diaspora happen? The Tishkoff team reckoned 100,000 years ago or less. Few believe nowadays that such dates are very precise but the regular clusterings of dates circa 100 KYA is striking.

There is an excellent editorial summary of Tishkoff, et al, on page 1364 of the same issue of SCIENCE by Joshua Fischman. A number of critics are quoted; most are not deadly focused critiques. They resemble the Americanist sceptics more than anything else but John Clegg of Oxford's team is running a test on beta-globin genes which may produce different results.

Of more detailed interest to us is that Agau Cushites (Ethiopian Jews) and Somalis seem closest to the ancestral population of the non-African world; their genes are inter-mediate between sub-Saharan Africa and the rest of the world. Or the great diaspora is most likely to have departed from northeast Africa, especial-ly the Horn. Of course, the geography virtually dictates that probability. The Egyptians are closer to Middle Easterners (Druze + Yemenite Jews).

Also the first serious gene study with Caucasic speakers in it occurred! The 98 Adyghe folk sampled are West Caucasic, most likely Circassians. Simplement dit, they are Europeans! Still a bit frustrating because it is not said whether they assumed the Adyghe were Europeans or concluded that it was so. Finally, it may not always be useful to lump Africans together as such -- Wolof, Yoruba, Biaka & Mbuti pigmies, Kikuyu & Herero Bantu, Khoi & San Bushmen. Their differences are significant; some of us are interested in that too!

Tishkoff, et al, say in their footnote 20 that "Information on origins of population samples, sampling procedures, and preparation of DNA samples can be found by checking from the Kidd Lab Home Page on the World Wide Web at ." Check it out!

Multi-regionalism took its second blow from fossil-oriented comparative study of crania, in-cluding faces (naturally). Here was centered the hard core resistance to 'Eve' theory and the anatomists from Weidenreich thru Coon to Aigner to Wolpoff. Marta Lahr's highly sophistic-ated, careful compilation and computations concluded that the flat faces (and other features) of Mongoloids were not local developments but present in older crania found to the west, especially in North Africa, and a robusticity in Pacific peoples was also matched in old Africa.

Highly interesting is the added (almost casual) finding that the antique Africans differ from modern Africans clearly -- to make the point that modern Eurasians are not derived from modern Africans but rather from ancient ones. We have known this in general terms for years now.

By analogy native Americans speak to the same point. Nearly universally derived from Asia in scholarly minds and most often seen as examples of archaic or earlier Mongoloids, these native Americans differ from modern east Asians in the direction of ancient east Asians. Some bio-genetic studies find specific links between Amerinds and Pacific peoples. Perhaps wisely, multi-regional theory has not tried to account for the native Americans in any way other than migration from Asia. (Source: Marta Mirazon Lahr, 1994. "The Multiregional Model of modern human origins: a reas-sessment of its morphological basis". JOURNAL OF HUMAN EVOLU-TION 26, 23-56. Her abstract says: "The Multiregional Model of modern human origins predicts that a group of features, recog-nized as characterizing the evolution of regional popula-tions from their archaic region-al ancestors, will consistently show higher incidence in those regions. This model also pre-dicts that regional morpholog-ical patterns are stable, reflecting absence of geograph-ical isolation. In order to test these assumptions, the incidence and distribution of the regional features proposed to character-ize the evolution of Chinese and Javanese Homo erectus into modern Chinese and Australian aborigines respectively were examined. The material studied were five recent populations and a fossil sample of anatomically modern Homo sapiens from the sites of Afalou and Taforalt. For this, a scoring system of grades was developed, so as to allow quantification and statis-tical testing. These analyses showed first, that although the majority of the features studied represent a regional pattern, this pattern does not always correspond to that proposed by the model; and a second, that some of these features occur in other populations with a higher frequency. Furthermore, the lack of special resemblance between the North African fossils and recent Africans suggest high levels of population different-iation. These results indicate that these features do not support a multiregional origin, giving further support to the existing fossil, chronological and genetic evidence for a single African origin of all modern humans."

In both articles Dr. Lahr uses a new word (for me), to wit, plesiomorph- or near-form. Normally applied to crystals which look alike but which have different chemical bases, it refers to forms which resemble each other for some reason but which do not necessarily have the same origin or basis. Thus resemblances between some fossil faces and some modern ones may be due to a shared feature, e.g., robusticity, which has similar effects on other shared features. It reminds me either of biology's analogous parts or the spurious similarities of historical linguistics. However, following Michael Day's defini-tion, a linguist would call it a shared retention. In any case plesiomorphy seems to have misled multi-regional theorists.

Marta Lahr has another fine paper on the same subject but focused on Amerinds. Her conclu-sions are rich and thought stimulating. They are in part, as follows: "1. The late appear-ance of regional morphological patterns suggests that the last common ancestor between Asian peoples and Amerindians did not conform to the typical Mongoloid description. Furthermore, it should be considered that earlier typological studies did not observe character origin and polarity when characterizing populations, and instead defined such terms as Mongoloids on the basis of the most typical or derived group. Within an evolutionary framework, such groups are the most autapomorph-ic, and therefore the least likely to throw any light into population relationships." "2. The populations from Tierra del Fuego and Patagonia, inhab-iting the southern periphery of the Amerindian geographical range and showing a very robust morphology that departs from a typical Mongoloid pattern, may be seen as a group that has retained to a greater degree the morphology of the first inhab-itants of the continent. As such, they provide evidence of heterogeneity within native Americans, and suggest that independent of the timing of first occupation, it is not possible to derive all the South American aboriginal populations from a morphologically derived ancestral source." "3. The long-observed relation-ships between certain fossil (European Upper Paleolithic, Upper Cave Zhoukoudian, Lagoa Santa) and recent (Ainu, Fuegian /Patagonian) populations and Australian aborigines should be given an interpretation in terms of differential retention of levels of robusticity rather than in terms of close phylo-genetic distances." End of Lahr.

Aut-apo-morph is Greek to me, even knowing what the parts mean (self-awayfrom-form). All dictionaries failed me and most physical anthropology texts. Michael Day's (GUIDE TO FOSSIL MAN) rescued us. The word means "A new morphological feature confined to one group in an evolving lineage". An example is severe cold adapted faces of so-called 'specialized Mongoloids' of the Arctic, only one lineage within a larger set of Mongoloid lineages. This all makes Coon a guilty 'autapomorphophile'. Heh, heh. (My humor is oft obscure.) In MT-27 (hopefully) we shall return to Michael Day's marvel-ous book and see some fruitful links between biological system-atics & historical linguistics.

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(c) 1996 Association for the Study of Language In Prehistory