Demography and H-Lea Salivary Secretion of the Maca Indians of Paraguay F. M. SALZANO, R. MORENO, M. PALATNIK' AND H. GERSHOWITZ Departamento de Gendtica, Universidade Federal do Rio Grande d o Sul, P8rto Alegre, Brazil; Instituto de Ciencias and Facultad de Ciencias Mddicas, Universidad Nacional, Asumi6n, Paraguay; Departamento de Ciencias BiolBgicas, Universidad Nacional, L a Plata, Argentina; and Department of Human Genetics, University of Michigan, A n n Arbor, Michigan ABSTRACT The Maci Indians living at Fray Bartolome de las Casas show a high rate of endogamy, high mortality (36% of them die before the age of reproduction), low fertility (average of 3.6 livebirths per female who completed her reproductive performance) and Iow variance in family size. The index of opportunity for selection (0.88)is lower than the one obtained in other populations of agriculturalists and in industrialized communities. The frequency of H secretors (N = 143) is 97% and that of Lea secretors ( N = 123) is 78%. The Mac2 are the modern descendants of groups identified by the names of Enimag& Guentuse and Lengua. Their language closely resembles that of those extinct groups and can be classified in the Mataco-Mac5 family of the MacroGuaicurd phylum (Mason, '50). At the time of the first contacts they were found in the Central Chaco, between the Bermejo and Pilcomayo rivers. Afterwards they migrated northeast to a place near the Verde river. Present groups live at two localities, Cuatro Vientos (59"55'W, 23'40's) and Fray Bartolome de las Casas (57"47'W, 25"20'S). In earlier times these Indians relied mainly on hunting and gathering for their subsistence. Many years of contact have somewhat changed their traditional ways of living but they are still reported as practicing only rudimentary agriculture (Susnik, ' 6 0 ) , leading an almost completely independent life and retaining their own language in a region where Guarani and Spanish are spoken by almost everyone. The only biological study of this tribe we have been able to locate is that of Urizar ('42) who studied 111 individuals for their ABO blood groups. Therefore, plans were made to obtain demographic and genetic information among them. Unfortunately, due to superstitious feelings they refused to donate blood to us. Thus, we had to restrict ourselves to the analysis AM. J. PHYS. ANTHROP.,33: 383-388. of their reproductive histories and salivary secretion. MATERIALS AND METHODS The population studied lives at Fray Bartolomk de las Casas, located near the city of Asuncih, Paraguay's Capital, from which they are separated by the Paraguay river. The Indians established themselves there in 1944, after a massive migration from Cuatro Vientos and Nanawa. The former locality is some 300 Km northwest, while Nanawa is only 35 Km away from Cuatro Vientos. They had to cross difficult, swampy land, led by the famous General J. Belaief. The reason for this migration was food shortage. Fray Bartolomk de las Casas is now an independent community under the supervision of the Associacih Indigenista del Paraguay. Missionaries of the New Tribes Mission have been working with them for some time, but as previously stated their degree of acculturation is still not high. Demographic information, saliva and a standardized photograph of each individual sampled were obtained by R. Moreno in January, 1965. The salivas were boiled just after collection and sent by air in an ice box to PBrto Alegre. They were tested there for H secretion (with a Ulex europeus extract) a few days after receipt, the ma2 Research career member of Argentina's Consejo Nacional de Investigaciones Cientificas y T6cnicas. 383 384 SALZANO, MORENO, PALATNIK AND GERSHOWITZ terial being kept stored at -20°C. Afterwards the salivas were sent by air to Ann Arbor, where repeat determinations for H secretion were performed, as well as tests for Lea secretion. But due to shortage of material and problems of transportation some salivas were tested in PBrto Alegre only. The techniques employed have been presented previously (Salzano, '64; Gershowitz et al., '67; Palatnik et al., '69). The protocols with the demographic data were also sent to Pdrto Alegre, where they were analysed by F. M. Salzano and M. Palatnik. The latter re-visited the group in December, 1968, and obtained some supplementary information about the Mach in Asunci6n in March, 1969. RESULTS Tables 1-5 present the data. A total of 466 individuals were included in the census, practically all of those living in Fray Bartolome de las Casas at the time. According to the Ministerio de Defensa Nacional del Paraguay the total number of Mac&Indians presently living in the country is 600. Therefore, our study covers 78% of the tribe. Since according to the same source the number of Paraguayan Indians is 37,570, the Mac& represent 1.6% of all Indians of that country. The estimated mean age of the Mac5 (table 1) is somewhat high as compared to those of other South American Indians living at comparable cultural levels (for a review see De Oliveira and Salzano, '69). There is an excess of males, as is true for four other tribes listed in the above cited paper. In relation to the Mach, we tried to find out if this high sex-ratio could be explained by an excess of female postnatal mortality. There is a slight excess of females in the reported deaths (74/143; 51% ) but it is too small to account for the unusual distribution. If we consider that Fray Bartolorn6 de las Casas was founded only 26 years ago by people who originated from Cuatro Vientos and Nanawa, in a strict sense the only exogamous marriages performed would be those involving other tribes. Only four such marriages were observed ( 3 between Mac5 and Chulupi Indians; 1 between Mach and Lengua - table 2). TWO Chulupi couples were also living in Fray Bartolomi de las Casas at the time of the investigation. Table 3 gives information about the fertility of the Mach woman. The number of livebirths per married female (3.4 F 0.2) is of the same order of magnitude as that observed among the Juruna (3.2 2 0.8), Xavante (3.1 2 0.2) and Bororo (3.0 0.5) Indians, but lower than the one found among the Caingang (4.5 C 0.1) (De Oliveira and Salzano, '69). The number of liveborn offspring in completed sibships observed here (3.6) is distinctly smaller than those obtained among the Caingang (6.1) and Xavante (4.7) (Salzano et al., '67); but it is higher than that reported for the Yanomama (2.6 - Nee1 and Chagnon, '68). A curious feature is the low variance observed among the Mach. Table 4 shows that the average number of surviving offspring per female who had at least one liveborn child is 2.2 0.1. The comparable figure in completed families is 2.4, with a variance of 1.2. Of the 376 individuals reported as born alive, 135 (36%) died before the age of reproduction. This figure is of the same order of magnitude as those observed among the Xavante (33% ) and Caingang (38%). Other Indian groups, however, like the Yanomama and Juruna, show much lower mortality. The breeding size of the Mac6 population (table 5 ) is 182, that is, 39% of the total population. Similar proportions between these two parameters were obtained * * TABLE I Distribution of the Mack population Sex Males Females Total Percent Sex ratio of Fray Bartolomd de las Casas by age and sex Age intervals 0-14 15-30 31andmore 71 61 132 28 116.4 43 50 93 20 86.0 81 68 149 32 119.1 Unknown 54 38 92 20 142.1 Total 249 217 466 114.7 Estimated average age Mean S.D. 27.5 26.3 20.8 19.5 385 DEMOGRAPHY AND SECRETION OF PARAGUAY INDIANS TABLE 2 Intratribal endogamy and intertribal marriages among the Macd of Fray Bartoloml de las Casas Marriages Endogamous NaxNas FBCxFBCs Total 53 62 1 1 10 12 64 75 Intratribal ( N ) (Mack) Exogamous 4Vx4V1 (%) 20 24 1 1 21 25 85 Mack x Mack Chulupi x Chulupi Mack X Chulupi M a d X Lengua 85 93 2 2 3 3 1 1 Intertribal ( N ) (% 1 14V. Cuatro Vientos. Grand total 4VxFBC 4 V x N a Total 2 Na, Nanawa. 3 FBC, Total 91 Fray Bartolome de las Casas. TABLE 3 FertiPity of the Mach woman Number of livebirths per married woman over the age of 15, by age groups 15-19 20-29 30-39 4049 50-59 4 5 0.8 63 23 2.7 121 30 4.0 68 18 3.8 56 Number of livebirths Number of females Average Dead 60 probably ~:IJ; 47 14 3.4 16 3.5 < 40 probably 5 40 8 2 4.0 11 3 3.7 359 106 3.4*0.2 Number of liveborn offspring in completed sibships Number of children Females with completed sibships Alive ( A 40 years) 40 years) Dead Dead (h40 years) Total (< Number Average no. of of Variance 0 1 2 3 4 5 6 '7 women children (SV 2 - -2 -7 -18 1 19 3.6 4.0 3.7 3.6 - 7 5 5 48 2 2 6 6 3 2 5 2 2 9 - - _ - 3 3 53 2.9 2.7 TABLE 4 Surviving offspringby age groups and i n completed families Average number of surviving offspring per female w h o had at least one liveborn child, by age groups Dead 60 15-19 20-29 Surviving offspring Number of females Average Decrease as % of livebirths ;t:e 5059 30-39 4049 ags Probably Probably 40 k40 0 2 0 3 2.3 100 38 / 3 4 0.7 42 22 1.9 66 30 2.2 45 18 2.5 36 15 2.4 36 13 2.8 228 102 2.220.1 13 30 45 34 31 18 35 7 Surviving offspring in completed families Females with completed sibships AIive ( A 40 years) Dead 40 years) Dead ( A 40 years) Total (< Number of children 0 2 _ 2 1 9 - - 9 2 10 2 1 2 23 - _ 1 2 5 4 3 1 _ - 4 3 - 1 3 Number Average no. Variance of of women children (") 46 2 3 51 2.5 0 2.3 2.4 1.1 - 1.2 386 SALZANO, MORENO, PALATNIK AND GERSHOWITZ TABLE 5 Some genetic parameters derived f r o m the demographic data and frequency o f t w o genetic markers 1st Breeding size 1 31 pd 0.36 Selection intensity a Genetic markers ABH Generations 2nd 3rd 78 Total 73 182 I, 4 If/PS I 0.56 0.21 0.32 0.88 Saliva secretion No. studied N 143 139 Sec. % 97 Gene Se 0.83 Lea ' Number of persons who left offspring. The length of this population. No. See. studied N % GeneLe 123 96 78 0.53 a generation was estimated as 20 years in 2 p d , premature deaths; I,, p d / p s , where p s = proportion surviving or 1-pd; I f , Vf/?a, where Vr = variance in offspring number in completed sibships and x'= mean number of livebirths per woman who completed her reproduction; I , Index of opportunity for selection, or p o t e n t i d selection; its genetic significance and usefulness are proportional to the genetic component in the phenomena on which it i s based: I =I, F/ps. See Crow, '58. + in other Indian groups. The index of op- The data reported here is, as far as we portunity for selection (Crow, '58) ob- know, the first which present demographic tained for the Mach (0.88) is identical to information of genetic interest and the inthe one calculated for the Yanomama and cidence of salivary secretion polymorvery similar to that observed among the phisms on these groups. Urizar ('42) observed one A and two B Xavante (Neel and Chagnon, '68). Other groups of agriculturalists and even indus- individuals among 111 Mach Indians studtrialized communities show, however, high- ied in Asunci6n for the ABO blood groups. er values (Spuhler, '62; Neel and Chag- This indicates the occurrence of some adnon, '68 ) . mixture with non-Indian groups. But if Relatively few studies have been per- this hybridization occurred it may have formed to date on the salivary secretion been restricted to previous generations, of American Indians. Only four tribes were since we did not detect any crossing even studied in South America (review in Sal- with Mestizos in our demographic study. zano, '64; see also Gershowitz et al., '67; The morphological appearance of our subArends et al., '67).Gene Se varied in these jects was also typically Indian. In this repopulations from 0.34 (Xavante) to 1.00 gard the Mach population seems to present (Guarani) and gene Le from 0.25 (Cain- the characteristics of a genetic isolate. Ungang) to 0.63 (Xavante). The Mach values fortunately the demographic data collected (Se: 0.83; Le: 0.53 - table 5) are in the were not sufficiently detailed to allow for middle of the distribution range. The gen- the calculation of the group's average ineral impression given by these values is breeding coefficient. But we may infer that that Se is more prevalent among North due to this isolation the coefficient would American Indians, where several samples be high. The population is characterized show values around 1.0. The distribution by large mortality, low fertility and low of Le in North American groups is still too variance in the number of both liveborn poorly known for comparison with the re- and surviving offspring in completed families. The average number of livebirths in sults in the South. completed sibships (3.6) is just a little DISCUSSION above the number necessary to attain the Few biological studies have been per- replacement level in a population with formed to date in Paraguayan Indians and such a high mortality before the age of rethey were restricted for the most part to production (36 % ). The low variance conblood group investigations (Urizar, '42; ditions an estimate of "effective" populaGajdusek, '64 and unpublished; Saguier tion number (Wright, '40) which is higher Negrete, '64; Miraglia and Saguier Negrete, than the breeding population, a situation '66; Matson et al., '68; Moreno et al., '68). that is probably very rare in human DEMOGRAPHY AND SECRETION OF PARAGUAY INDIANS groups. At present it is not clear whether this low variance is real, due to underreporting or to any other unknown deficiency of our method of data collection. The salivary secretion studies furnish information on two genetic markers only, evidently too few for any attempt at correlation with the population structure results. The only indication they give is that of a “typical South American Indian” prevalence, in keeping with the low estimates of Mac& interbreeding with non-Indian persons mentioned above. Papers dealing with both genetic and demographic aspects of human populations are appearing with increasing frequency (see, for instance, besides the papers already cited here, Johnston et al., ’69; Basu, ’69). The importance of such investigations for the understanding of our evolution cannot be overemphasized since the genetic diversity of a group is conditioned to a large extent by its population structure. The main task ahead is the proper Iinking of the genetic and demographic results. A decisive step in this direction has recently been made by Ward and Neel (’70) with their new index of genetic migr a tion. ACKNOWLEDGMENTS The financial support of the following institutions is gratefully acknowledged: Consejo Nacional de Investigaciones Cientificas y Tknicas, Argentina; Conselho Nacional de Pesquisas, Brazil; Conselho de Pesquisas da Universidade Federal do Rio Grande do Sul; Coordenaq5o do Aperfeifoamento do Pessoal de Nivel Superior, Brazil; Fundafiio de Amparo B Pesquisa do Estado do Rio Grande do Sul; U.S. Atomic Energy Commission grant AT(111)-1552; and the Wenner-Gren Foundation for Anthropological Research. LITERATURE CITED Arends, T., G. Brewer, N. Chagnon, M. L. Gallango, H. Gershowitz, M. Layrisse, J. Neel, D. Shreffler, R. Tashian and L. Weitkamp 1967 Intratribal genetic differentiation among the Yanomama Indians of southern Venezuela. Proc. Nat. Acad. Sci., 57: 1252-1259. Basu, A. 1969 The Pahira: a population genetical study. Am. J. Phys. Anthrop., 32: 399-416. Crow, J. F. 1958 Some possibilities for measuring selection intensities i n man. Hum. 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Robinson 1968 Distribution of blood groups among Indians in South America. VI. In Paraguay. Am. J. Phys. Anthrop., 29: 81-98. Miraglia, L., and E. Saguier Negrete 1966 Osservazioni somatiche e sierologiche sulla razza Guayaki. Boll. SOC.Natur. Napoli, 74: 375-395. Moreno A., R., E. Saguier Negrete, A. Arce Queirolo, J. F. Mohn and R. M. Bannerman 1968 Grupos sanguineos y otros marcadores genbticos en indios Chulupies y mestizos del Paraguay (Comunicaci6n previa). Rev. Med. Paraguay, 9: 57-62. Neel, J. V., and N. A, Chagnon 1968 The demography of two tribes of primitive, relatively unacculturated American Indians. Proc. Nat. Acad. Sci., 59: 680-689. Palatnik, M., M. J. F. de SB e Benevides and F. M. Salzano 1969 ABH salivary secretion and White/Negro gene flow in a Brazilian population. Hum. Biol., 41: 83-96. Saguier Negrete, E. 1964 El sistema sanguine0 Diego y el origen mongol6ide de nuestros indios. Rev. Med. Paraguay, I : 3+34. Salzano, F. 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Nee1 1970 Gene frequencies and microdifferentiation among the Makiritare Indians. IV. A comparison of a genetic network with ethnohistory and migration matrices; a new index of genetic migration (manuscript).