LINGUISTIC AND GENETIC RELATIONSHIPS IN NORTHERN CAMEROON Brett C. Haberstick1 Erin Shay2 Eric Johnston2 Gary L. Stetler1 John K. Hewitt1 Andrew Smolen1 Zygmunt Frajzyngier2 1 Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309-0447 2 Department of Linguistics, University of Colorado, Boulder, CO 80309-0295 The authors wish to thank the Butcher Foundation for their support of the Northern Cameroon Language and Genes Project [NCLGP] as well as Brad Pemberton and Taylor Roy for their technical assistance related to this project. Introduction The goal of this study is to explore the correlation between related languages and the genetic relationships of the populations that speak them. The narrower goal is to examine whether individuals of languages from the same language family or the same branch of a given family exhibit a closer genetic relationship than individuals belonging to different language groups or subgroups. For this purpose, genotypes for 28 autosomal genetic markers were determined from samples obtained from about 30 speakers of each of six different languages belonging to two different language families spoken in Northern Cameroon. Genetic relationships established using the genetic data were correlated with established relationships among languages spoken by those who provided samples. Background Several prior studies have sought correlations between linguistic classification and genetic distance among the language populations of Cameroon. Like the present study, these studies take for granted the established linguistic classifications. Because the methods of genetic sampling and analysis differ, the results of these studies are not always comparable. There have been very few studies dedicated to the Chadic-language populations of Cameroon. In two studies, Spedini and colleagues [1999, 2001] analyzed the distribution of ten protein genetic polymorphisms in eighteen populations belonging to three linguistic families represented in Cameroon, namely Afroasiatic; Nilo-Saharan; and the West-Atlantic, Adamawa eastern, and Benué-Congo branches of Niger-Kordofanian. The Afroasiatic family is represented by the Chadic languages and by Shua Arabic. Among the Chadic languages, Spedini et al. have examined Daba, Giziga (Guiziga, in their spelling), Mafa, Mada, Uldeme, and Podoko (Podowko, in their spelling), belonging to the Central Chadic branch, and Masa (Massa in their spelling), all of which belong to the Masa branch as per the Newman 1977 classification. Spedini et al. postulate a partial correlation between linguistic distance and genetic distance, concluding that ‘the language-family relationship between populations contributes more than their geographic location to the genetic differentiation among Chadic speakers (but not among Niger-Kordofanian)’ (Spedini et al. 1999: 156). erný et al. [2004] examined mitochondrial DNA sequences for Hdi (which they call Hide), Kotoko, Mafa (all Chadic languages of the Central branch), and Masa (Masa branch). The data are compared with published findings for other populations in Africa. The authors conclude that speakers of the four Chadic languages in their study are more closely related to populations in East Africa than to populations in West Africa, pointing out that such similarities may be due to prehistoric migrations or to more recent interactions between the populations. Linguistic Relationships A language family is a group of languages thought to be descended from a common ancestor. The members of a language family may be grouped into branches and sub- branches whose members are thought to be more closely related to one other than to members of other branches or sub-branches. The current study is based on genetic data gathered from speakers of six different language groups [five from the Chadic family, one from the Niger-Congo family] in a relatively small area of Northern Cameroon. Within the Chadic family, four languages [Gidar, Mina, Hdi, and Mafa] belong to the Central (also called the Biu Mandara) branch while one language [Peve] belongs to the Masa branch. From the Niger-Congo language group, we sampled speakers of Mambay. Previous research has established the linguistic relationships among these languages using the standard comparative method [Newman (1977) for the Chadic grouping, Boyd (1989) for the Niger-Congo grouping]. For the purposes of the current study, we take these relationships as given. Basis for language group selection In order to maximize the detection of common population genetic structure between groups, language groups were selected first by language family and then by geography. For example, within the Central branch of the Chadic language family, Hdi and Mafa were sampled because they are spoken within the immediate vicinity of each other; thus these languages are close both linguistically and geographically. Gidar and Mina language groups, also of the Central branch, are also spoken in the immediate vicinity of one another, though each belongs to a different sub-branch within the Central Chadic language family grouping. A comparison of the genetic relationships between Hdi and Mafa on the one hand and Gidar and Mina on the other hand may reveal whether linguistic distance, geographical proximity or both are reflected in the genetic structuring of these respective populations. Peve, which belongs to the East branch of the Chadic family, was chosen because it is only distantly related to the other four Chadic languages selected for participation. Mambay was chosen because it belongs to the Niger-Congo family and thus is not linguistically related to any other languages in the study [Boyd, 1989]. Because Mambay is spoken in the geographical area close to where Peve is spoken, including these two language groups allows an examination of the genetic relatedness when two groups are geographically proximate and linguistically unrelated. Comparisons between Peve and the other Chadic languages examined here allow an examination of the genetic relatedness when two groups are linguistically related, geographically remote. As a whole, each of the six distinct language groups identified for participation facilitated asking whether the complete absence of linguistic relatedness also suggested population genetic divergence. One further consideration in selecting the language groups was that several of the investigators have previously published work on the Hdi, Gidar, and Mina languages [Frajzyngier, in press; Frajzyngier et al, 2005; Frajzyngier and Shay, 2002] and have developed working familiarity with the chosen groups. Furthermore, the investigators were able to employ a speaker of Peve who is interested in studying his own language and who assisted in the collection of the genetic samples used in the current study. Social relationships and historical interactions The language populations from which genetic samples were obtained have had varying degrees of interaction over time. Hdi is a relatively small language, with estimates varying between 15,000 to 30,000 speakers. Mafa, the largest language group selected for study here, number more than 100,000 speakers and occupies a large area of the extreme Northern Province of Cameroon, and surrounds the Hdi population on three sides. There has been much commercial trading and intermarriage between the Hdi and Mafa populations, with Mafa women sometimes marrying into the Hdi community and Hdi women marrying into the Mafa community. The primary factors determining intermarriage between these two populations are economic rather than cultural [e.g. there is no linguistic exogamy requirement]. Some Mina and Gidar settlements are separated by as little as 15 kilometers, but the historical and cultural centers of the Gidar and Mina populations are a considerable distance apart [see #39 and #61 on Figure 1]. The Mina population, whose speakers number roughly 11,000, were a dominant military force in the area during the 1800’s. There are more Gidar speakers than Mina speakers, with estimates ranging from 40,000 to 70,000 [Ethnologue]. According to Podlewski [1965], there has been a considerable degree of intermarriage or admixture between Gidar speakers and other populations [not specified by Podlewski]. Peve, the smallest language groups selected for our study, is spoken by approximately 5,720 speakers and is a dialect of Zime, a language spoken by over 100,000 speakers in Cameroon and nearby Chad. The Peve settlement borders the area where Mundang [#56 in Figure 1] is spoken. Although Peve and Mambay [spoken by roughly 8,000 speakers] belong to different language families, both languages border on the area where Mundang, a member of the Niger-Congo family, is spoken. Peve speakers have had considerable linguistic and social contact with Mundang, and many Peve speakers speak Mundang as a second language. The degree of mutual understanding between Mambay and Mundang has been estimated at about 47% [Hamm, 2002]. There are occasional intermarriages among Mambay and Peve speakers. In those situations, Peve men have settled among Mambay, with fewer cases of Mambay men settling among Peve. Goals of the study Our objective was to determine whether the degrees of relatedness determined by our genetic data would reflect the degrees of relatedness as determined by the linguistic relationships described above. Thus we hypothesized speakers of languages belonging to the Chadic language family would be more genetically similar to each other than to speakers of the Niger-Congo language, Mambay. In