AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 114:361–364 (2001) Biological and Cultural Contradictions? A Reply to MacEachern Gabriella Spedini,1* Stefano Mondovı̀,1 Giorgio Paoli,2 and Giovanni Destro-Bisol1 1 Department of Animal and Human Biology, University “La Sapienza,” 00185 Rome, Italy 2 Department of Ethology, Ecology, and Evolution, University of Pisa, 56126 Pisa, Italy In his comment appearing in this issue of the American Journal of Physical Anthropology, MacEachern (2001) questions some conclusions drawn in our longterm survey of genetic variation in Cameroon (Spedini et al., 1999). In our reply, we would like to clarify certain points so as to put AJPA readers in a position whereby they understand both viewpoints. WHAT DOES ISOLATION OF PODOKWO AND ULDEME MEAN? The main point in MacEachern’s critique concerns our claim that the genetic structure of some Montagnard populations has been shaped by the combined effect of genetic drift and isolation. Before discussing MacEachern’s considerations about ethnographic sources, estimates of endogamy rates, and cultural evidence, we would like to clarify the exact meaning of the term “isolation.” The method we used, kinship analysis, does not give an absolute estimate of isolation. It simply compares a number of populations and identifies which are the most (or least) isolated. Therefore, our results do not imply that the Podokwo and Uldeme Montagnard are completely isolated, but simply that these two groups are more isolated than the others. Standard scientific and statistical procedures require any comparison to be carried out on a sufficiently ample portion of the original data set. However, MacEachern was concerned only with 4 (Mada, Mafa, Podokwo, and Uldeme) out of 18 populations studied in Spedini et al. (1999). Scientifically speaking this subset is too small, which limits the validity of MacEachern’s conclusions. ETHNOGRAPHIC SOURCES MacEachern claims that the ethnographic sources of our paper are somewhat outdated. However, he does not give any details or, at least, citations of studies. Readers ought to understand the criteria by which we have chosen our ethnographic sources. First of all, the term “outdated” is inappropriate. Some of our ethnographic sources (Boutrais, 1973, Boutrais, et al., 1984; Marguerat, 1976; Boulet and Seignobos, 1978; Hallaire, 1991) are more recent than some of the works cited by MacEachern (Juillerat, 1971; Richard, 1977; de Colombel, 1986). In © 2001 WILEY-LISS, INC. addition to this, and more importantly, our ethnographic sources are the results of long-term surveys in which a large number of populations settled over a broad geographical area was studied simultaneously using the same methodology. This makes them a reliable source of information. On the other hand, the studies considered by MacEachern are mostly based on small, geographically limited populations, and the studies conducted were methodologically heterogeneous. Therefore, it cannot be denied that ethnographic sources produce at least two alternative views on the degree of isolation of Montagnards. Our genetic study provides a test of these two different views, and favors the one sustaining the existence of marked isolation among Montagnards. ESTIMATES OF ENDOGAMY RATES IN NORTHERN CAMEROON MacEachern raises serious doubts concerning our estimate of a 100% endogamy rate among Montagnards (see Table 4 on p. 152 of Spedini et al., 1999). However, we would like to point out that a similar 95% endogamy rate was also observed among Podokwo by Podleskwi (1966). No substantial evidence against our and Podleskwi’s estimates is given by MacEachern. He quotes a number of studies which indicate a marked variability in the endogamy rates of Montagnards, with very high endogamy rates in the Muktele (92–95%; see Juillerat, 1971), “neighbors of the Podokwo.” The field notes collected by the author himself among the Uldeme/ Plata would seem to contradict our estimates of endogamy in the Uldeme. Unfortunately, a comparison of the two studies is not possible, since MacEachern does not give a point estimate but rather a range of values (60 –70%). Furthermore, the sample size is not reported, and the endogamy estimate of MacEachern is questionable. In fact, he carried out his investigation on a sample of Montagnard women producers of local pottery. The author himself points out that these women “circulate among patrilocal communities in the course of frequent marriages and remarriages.” Possibly, a more varied sample from all areas of the community would have been more appropriate. MacEachern does not indicate whether exogamic marriages occur more frequently among female potters than among female nonpotters, as would seem possible. Thus, it is unclear Grant sponsor: CNR; Grant number: 000516.98.CT04; Grant sponsor: University of Rome “La Sapienza” 60% Funds. Grant sponsor: M.U.R.S.T.; Grant Number: MM05038334, Cofin. 2000-2001. *Correspondence to: Gabriella Spedini, Department of Animal and Human Biology, University “La Sapienza,” P. le A. Moro 5, 00185 Rome, Italy. E-mail: email@example.com Received 19 October 2000; accepted 19 November 2000. 362 G. SPEDINI ET AL. whether a marked difference in the potters’ matrimonial behavior from the average could have led to some confusing results. We would like to point out that new data collected in the original locations of Montagnards (villages of Godigou and Mayo Uldeme in northern Cameroon; Spedini, 1998, unpublished data) provide further evidence of a high endogamy rate both for the Uldeme (100% endogamy rate, a total of 50 marriages considered) and Podokwo (95.1% endogamy rate, a total of 41 marriages considered). GENETIC AND CULTURAL EXCHANGE MacEachern claims that a cultural exchange between populations should automatically homogenize their gene pool. He fails to take into account two basic principles concerning cultural and biological evolution. Firstly, cultural exchange does not necessarily imply gene flow and vice versa. Secondly, there is a significant difference in time scale between cultural and genetic evolution, so that genetic effects may appear many generations after any cultural and/or social changes. GEOGRAPHIC DISTANCES AMONG MONTAGNARDS MacEachern expresses some doubts concerning the precision of the geographic distances we used to assess the correlations between geographic and genetic diversity. Using our map (Fig. 1 on p. 149 in Spedini et al., 1999), he infers that we have considered a total distance across the territories of the Podokwo, Uldeme, and Mada of approximately 80 km, which is much larger than his value of 15 km. His map (Fig. 1 in MacEachern, 2001) better depicts the area of settlement of Montagnards. At the end of his comment he states, “One hopes that data from the map were not used in the calculation of geographic distances matrices produced in the paper.” The issues raised by MacEachern need to be reconsidered for four reasons. Firstly, it may be useful to describe briefly how the geographic distance between populations was calculated in our studies. Since the Montagnard populations are settled in different villages, one should use the distance between the center of the areas covered by each population, or alternatively, the distance between the point central to the most populated villages. A fine-scaled map is obviously necessary. Using this method, we obtained a distance of 10 km between Podokwo and Uldeme, 5 km between Uldeme and Mada, and 15 km between Podokwo and Mada. Secondly, the numbers on our map (as on all maps of this kind)are used only to show the relative position of populations and not their exact locations. This is simply due to the fact that the numbers need to be well separated so that they are easily distinguishable. Thirdly, even if we accept MacEachern’s speculation that numbers on the map indicate the location of populations precisely and use the distance between topologically well-defined points as a reference, it remains quite unclear how MacEachern could have obtained the precise value of 80 km. In fact, the recalculated distance (in kilometers) between numbers changes depending upon which exact point one considers within the microarea on the page covered by the number. Notice that the distance recalculated in kilometers between the Mada (number 3 in Fig. 1 on p. 149 of Spedini et al., 1999) and Podokwo (number 6) varies from 65 km (using the closest points) to 92 km (using the most distant points; see Fig. 1 in this paper). Therefore, the recalculation of the distance between some Montagnard populations made by MacEachern is not only inappropriate but also approximate. Finally, the map published by MacEachern does not contain any known geographical reference, which makes it impractical for use. ALTERNATIVE HYPOTHESES FOR THE GENETIC DIFFERENTIATION AMONG MONTAGNARDS Every critique of any conclusion based on a scientific approach should be accompanied by testable alternative hypotheses. Unfortunately, this is not the case with MacEachern’s paper. He invokes “the existence of larger, less precisely demarcated regional groupings that are also visible in both ancient and modern distributions of material culture.” In a subsequent part of the paper he affirms that “genetic differentiation of a Mada, Podokwo, or Uldemé population sample . . . could indicate relative genetic differentiation between broader regional populations, within which each of those ethnicities is only a part.” Some of the terminology used here seems a little vague and ambiguous. For example, “regional groupings” seems to imply a certain degree of isolation. However, MacEachern repeatedly claims that there is a high gene flow among Montagnards. Furthermore, in his first sentence he once more stresses the idea of a precise link between cultural and genetic change. “POST HOC INTERPRETATIONS?” MacEachern criticizes how we integrate biological and cultural evidence. He accuses us of having created an artifactual link between genetic and historical data. He seems to be reiterating the classical claim of “post hoc interpretations” by Binford (1981, p. 31–32) against ingenuous explanations developed after an analysis is completed. His criticisms are based on three points: 1) the use of “outdated ethnographic sources;” 2) the lack of genetic differentiation of Mada and Mafa from other northern Cameroonians; and 3) the view that during the Holocene there was a process of sedentarization in a limited number of nuclei. Point 1 has been discussed above. Concerning the second point, MacEachern has not adequately con- BIOLOGICAL AND CULTURAL CONTRADICTIONS 363 Fig. 1. Variation in distance between the Mada (number 3) and the Podokwo (number 6), recalculated from Figure 1 on page 149 of Spedini et al. (1999). Dotted line depicts minimum distance (65 km), whereas the solid line depicts maximum distance (92 km). The distance between western (point A) and eastern (point B) extremities of the southern border of Cameroon was used as a reference (airline distance, 718 km). sidered that the local kinship value (a relative measure of isolation) of the Mada (0.0163) is lower only than those of Uldeme (0.045), Podokwo (0.037), and Tali (0.022) (see Table 7 on p. 154 in Spedini et al., 1999). Furthermore, he does not mention that the Mada and Mafa cluster separately from other populations in the UPGMA tree shown in Figure 4 of our paper (Spedini et al., 1999), which further suggests a certain degree of genetic differentiation of these two populations from other Afro-Asiatic-speaking groups. The third point of contention is the least understandable. The concept of a limited number of nuclei of sedentarization is not ours, but is a synthesis of the evidence presented in various studies, none of which is cited by MacEachern (e.g., Lebeuf, 1981; David, 1981; Essomba, 1991; see also citation on p. 144 –145 of Spedini et al., 1999). MacEachern claims that the archeological reconstruction of processes of sedentarization is invalid, since it may be biased by the geographic localization of excavations. In any scientific debate one can only make inferences based on evidence available at the time and considering current views. Obviously, it is possible that these views could change in the future as new data are collected and as they inform research. It would have been useful to find out whether MacEachern has substantial reasons to oppose the view of a limited number of nuclei of sedentarization, but unfortunately he does not comment on this. 364 G. SPEDINI ET AL. On the other hand, MacEachern’s view about processes of sedentarization in prehistoric Cameroon is rather drastic, since a similar perspective would eliminate the validity of many archeological studies. This would be a pity, because archeological studies combined with research from other scientific areas have shed light on many important aspects of population histories. EPILOGUE: HOW WE CAN HELP CREATE A CONSTRUCTIVE DIALOGUE BETWEEN CULTURAL AND PHYSICAL ANTHROPOLOGISTS Our analysis of MacEachern’s arguments suggests that had he analyzed our data a little more closely, he might have drawn quite different conclusions. Our work apart, we would like to comment on the usefulness but also on the potential danger of the message given by MacEachern. He highlights once more that there is a problem of communication between cultural and biological disciplines. It is clear that both these fields of research would benefit from working in tandem. Among the issues raised by MacEachern, problems concerning ethnic self-identification should be more carefully considered by biological anthropologists. At the same time, our analysis of MacEachern’s contribution illustrates how an understandable lack of knowledge about principles and methods of field of research that are different from our own may result in the misinterpretation of works carried out by colleagues in other areas. While in our case MacEachern clearly has overlooked the biological evidence, one could easily find peer-reviewed papers published by physical anthropologists and/or population geneticists in which cultural evidence is not adequately considered. The problem is that biological and cultural anthropologists have difficulties in understanding differences and similarities between their scientific approaches, and therefore find any subsequent form of interaction or collaboration difficult. To increase the cultural flow among researchers, it could be useful for biological and cultural anthropologists to meet for discussions, perhaps inviting researchers from both disciplines with a common interest in specific populations. Given the attention of the American Association of Physical Anthropologists (AAPA) to multidisciplinary research, we feel that the symposia organized by the AAPA could be the ideal place to start building a bridge between these two distant but, at the same time, close disciplines. LITERATURE CITED Binford L. 1981. Bones: ancient men and modern myths. New York: Academic Press. Boulet J, Seignobos C. 1978. Le nord du Cameroun: bilan de dix ans de recherches. Paris: ORSTOM. Boutrais J 1973. La colonisation des plaines par les Montagnards au nord du Cameroun. Monts Mandara.. Paris: ORSTOM. Boutrais J, Boulet J, Beauvilain A, Gubry P, Barreteau D, Dieu M, Breton R, Seignobos C, Pontie G, Marguerat Y, Hallaire A, Frechou H, editors. 1984. Le Nord du Cameroun. 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