The spread of animal and plant domesticaion is now frequently argued to be associated with the dispersal of language families, both via demic diffusion, the actual migration of expanding populations over space (Ammerman and Cavalli-Sforza 1984), instead of cultural diffusion. Such movement would have implications for spatial patterns of genetic variation. This claim for a coterminous spread of genes, language [families] and/or food production is most successfully made by reconciling data and interpretations from genetics, historical linguistics, and archaeology. When sufficient evidence is available a multidisciplinary approach requires testing all models.
In terms of Africa one interesting case regards the Afroasiatic language phylum or family. The spread of domesticated wheat, barley, goats and sheep into northern Africa from southwest Asia (the Near East) and its relation to the Afroasiatic language family is a good example. A minority argue that Afro-asiatic is Asian in origin (which requires opposing standard linguistics evidence), the majority that it is African. Either position on origins influences any subsequent interpretations. Unfortunately both models are not usually presented in published work; an imbalanced picture is presented. Most genetic studies and/or interpretations have proceeded from models in which either ancestral Afroasiatic or a later branch, e.g. Berber (Arredi et al. 2004) are posited to have come from the Near East with the spread of food production, without the consideration of alternatives which is problematic when not simply wrong. Generally population migration versus cultural diffusion is given the primary responsibility as the mechanism of change. Here is explored the ramifications of taking into account the views of mainstream linguists, as well of archaeology, in the examination of the genetic data. The issue the construction of the most credible narrative, that is balanced and fair.
The study of individual Afroasiatic languages, and then later the family itself, formally called Hamito-Semitic, or Semito-Hamitic, has a long history. The great interest, at least in part, is because this family gave rise to the Semitic languages found in the texts used in Judaism, Christianity and Islam. Ancient Egyptian is the other member that received substantial attention. Afro-Asiatic has another distinction related to the study of African peoples, because it is connected to a theory of biological and cultural origins called the “Hamitic hypothesis” promulgated by C.G. Seligman (see Sanders 1969). This thesis posited that Southwest Asian peoples called “Hamites” , distant relations of Semites, came into Africa bringing a new language family, pastoralism, “superior” culture, and unique (and “superior”) biology marked by narrower noses and faces, straighter hair, and lighter skin color, although curiously not the skills of plant agriculture. Nearly all instances of culture in Africa deemed to be noteworthy from a western perspective were attributed ultimately to contact with Hamites. Certain body builds and physiognomies when not found among “Hamitic” speakers were said to be due to “Hamitic” (read ““Caucasian”) admixture. Thus many African societies by this myth were rendered non-African; aspects of this way of thinking continue.
The Hamitic hypothesis was overturned largely by Greenberg, and abandoned by Africanist historians. The majority of historical linguists who study the family read the evidence as supporting that Afro-Asiatic is a family of African origin and history, with one branch, Semitic, having had an ancestor that was carried to Asia (the Near East). They generally agree, based on evidence, that the proto-language was spoken by hunters and gatherers, not seed farmers or pastoralists (i.e. food producers) which is a very important observation. The principle of greatest diversity indicates Africa to be the geographic cradle, and of the concept of “least moves” that the Horn of Africa or southeastern Sahara is the more specific locale of the ancestor. It is generally true that the place of greatest diversity of an ‘evolving’ population or language, all other things being equal, is its likely place of origin. Care has to be taken to understand that in theory if a broad sample of a population migrated that the level of diversity or something close might travel with it. Of equal interest is that the branch of Afroasiatic, Omotic, believed to be the least derived in its relationship to the ancestral proto-family is found only in the Horn of Africa, specifically Ethiopia; if this branch is not considered to be in the family it becomes the nearest relative to the group and still anchors the proto-family in Africa. Studies involving genetics, Afroasiatic, and food production should always examine hypotheses based on the different models of geographical origins, and the internal structuring of a language family.
What happens when genetic and linguistic data are considered in terms of the African origins model? The recent spread of Arabic has to be ignored and the presence of Semitic languages in Ethiopia--based on the standard linguistic interpretations. The Y chromosome data are used because they are the most complete for the greatest number of members of the family. The core distribution of the family runs from eastern Africa north to Egypt and west along the Mediterranean littoral. The subfamilies spoken or once spoken here are Cushitic (Kenya, Tanzania, Somali, Ethiopia, and Sudan), ancient Egyptian in the Egyptian Nile Valley, and Berber spoken in Siwa Oasis of Egypt and west to Morocco, and south into Mali and Mauretania. Collating the data from various studies indicate that the TaqI 49 a,f haplotype V is the predominant variant in this region overall; it has notably lower frequencies in the Near East (Table I). This is exactly what would be expected for an African model of origins—assuming that the language family was initially and primarily spread by the migration of humans, and not by cultural diffusion. Furthermore genetic studies that were not concerned with language confirm this. For example Underhill et al state that the M35 lineage was carried into the Near East from Africa in the “Mesolithic”; this M35 in Africa corresponds to the TaqI 49 a,f V. It is far more likely that pre-proto-Semitic speakers went into the Near East at this time where Semitic languages have long since dominated, but the predominant haplotypes in most Semitic speaking populations are variants VII and VIII in the TaqI 49 a,f system (al-Zahery), which are equivalent to M89 associated lineages. The most parsimonious explanation is that ancestral Semitic was adopted by those bearing haplotypes VII and VIII. (Incidentally it is not argued here that there has not been some two-way migration between Africa and Asia, but in this instance the predominant migration was from Africa; the underived M35 lineage is found primarily in East Africa, and most of the variation in derived and related clades are in Africa.)
Wheat and barley agriculture in Africa is first attested in northern Egypt around 5200 BC dating to some 2000 years after its emergence in Asia (the Near East); very significantly it appears as another item in a foraging strategy, not as a total change in subsistence pattern (Wetterstrom 1993). This is not consistent with a mass migration hypothesis involving farmers from Asia (the Near East) who would have come as settler colonists. By this time Afroasiatic had already begun to differentiate or was already differentiated at some level. Among the earliest agriculturalists in Asia (the Near East) were speakers of common Semitic based on vocabulary reconstructions (Diakonoff 1998). If there had been mass migration of rapidly multiplying farmers into Africa those who came to be known as the ancient “Egyptians” would have been Semitic speakers. Curiously not even the terms for sheep, goat, wheat, or barley in ancient Egyptian are Semitic loan words; this is another interesting finding that has historical implications. This example reveals the value in examining older and newer linguistic work in relation to genetic studies, as well as archaeological data.
Afroasiatic and its speakers offer other fascinating findings which invite a critical historical enquiry. Chadic speakers living primarily in the central Sahara and northern Nigeria have a very high frequency of an M89 lineage of an R1 sub-clade. These Chadic speakers phenotypically are generally very dark skinned with frizzy hair the facial conformation often thought of as representative of “the African” a point that will be revisited later in relationship to the classification of Chadic within Afroasiatic. Curiously the frequency of this lineage is far greater in some saharo-tropical population samples (over 90%) samples than it is in the Near East—its putative place of origin. The frequencies of R1 are not nearly as high in Nile Valley Egypt and other parts of Supra-saharan Africa. What are the historical explanations for this lineage and its distribution, or what could they be? Some writers have postulated that the presence of the lineage corresponds to bearers of the Chadic family of Afroasiatic spreading into the central Sahara based on the presence of the V88 marker and called R-V88 (Cruciani et al. 2010); for some this would be reminiscent of the Hamitic hypothesis but should not be confused with that project because of the relatively low frequency of this clade in other branches of Afroasiatic. Interpretations of Y chromosome data including STR variability from Equatorial Guinea suggest that the V88 marker may have arisen on an R1 background south of the Chad basin and spread north instead of the reverse (Gonzalez et al. 2012). It may very well be that the language family spread independently of the lineage, with the lineage being in the region before the Chadic language family. The presence of an R sub-lineage could be simply conceptualized as a Paleolithic “back migration” without any necessary cultural implications; in this scenario it becomes a part of the biological ancestry of regional peoples subject to local adaptive evolutionary forces. Its distribution in the circum-Saharan areas may reflect later movements of Saharan peoples during mid-holocene droughts. Another explanation is that some areas of the central Sahara and Nigeria were settled in part by Assyrian refugees in the last millennium BC (see Lange 2011), an interpretation of evidence that has not gained wide acceptance among historians.
It is of some historical interest and still very revealing that although linguists some linguists in the early twentieth century thought that Chadic was Afroasiatic, others greatly resisted its classification into the family (Newman 1980). This was not based on linguistic data but rather on the fact that the Chadic speakers were “black” or “blacker” than other members of the family (Ruhlen 1991). This illustrates the problem, leaving alone the bias for a moment, of having expectations that all connections or relationships would be between entities perceived as being uniform in all respects. This issue is made even more ironic when it is understood that some groups of sampled Chadic speakers have a higher percentage of a “Eurasian” Y lineage than do others who were categorically seen as more akin to Europeans.
