Markers of genetic variation among the Waorani Indians of the Ecuadorian Amazon headwaters

Until recently, the Waorani Indians of Ecuador's Amazon headwaters maintained a fierce resistance to all intruders into their territory, and as a result of their actions and reputations a population of 600 people controlled a very large territory (about 8,000 square miles). The isolation of the Waorani has resulted in a large linguistic and genetic distance from their neighbors. Our survey of red cell enzymes, immunoglobulin allotypes, and dermatoglyphics demonstrates that the Waorani are a highly inbred and homogeneous population. Of 18 red cell enzymes studied, the Waorani have a limited polymorphism for only 6. Only two Gm haplotypes (Gm1,2,17,21, Gm1,17,21) were found and 60% of those tested were homozygous for the Gm1,17,21 haplotype. All individuals were A2m (1) and 95% of these were homozygous. The Waorani's dermatoglyphic traits fell within the wide range found among other South American Indians with close affinity to the Ecuadorian Jivaro group. Despite the limitations of these genetic systems, they demonstrate that the Waorani share limited genetic traits with the neighboring Jivaro Indians and are isolated from other tribal populations in South America.     

Polydactyly in the American Indian.

Polydactyly has an incidence in the American Indian twice that of Caucasians. A minimum estimate of this incidence is 2.40 per 1,000 live births. Preaxial type 1 has an incidence three to four times that reported for Caucasians or Negroes. The overall sex ratio in Indians is distorted with more males affected than females. The preaxial type 1 anomaly has a strong predilection for the hands and always is unilateral in contrast to postaxial type B where more than one-half are bilateral. The evidence to date, consisting of varying incidences of specific types of polydactyly among American whites, Negroes, and Indians in varying enviroments, suggests different gene-frequencies for polydactyly in each population. The incidence in Indians with 50% Caucasian admixture suggests that the factors controlling polydactyly are in large part genetically determined. Family studies and twin studies reported elsewhere offer no clear-cut genetic model which explains the highly variable gene frequencies.     

Anterior femoral curvature: Its probable basis and utility as a criterion of racial assessment

Stewart ('62) and Walensky ('65) indicated that while the metrical expression of anterior femoral curvature alone will not always differentiate between Whites, American Negroes, and North American Indians, it was very useful as a racial criterion in combination with observed traits such as torsion, pilastry, and cross-sectional shape. Seven additional North American Indian groups reported here, representing both pre-Columbian and post-contact times, upheld the observation that anterior femoral curvature is a useful feature of racial assessment for Negroes, Whites and North American Indians. However, two South American groups studied (Ecuador and Peru) were only slightly more curved than American Negroes, and were less curved than Whites and North American Indians. The metrical expression of anterior femoral curvature therefore is not a useful feature of racial assessment for separating these two South American Indian groups from Whites and American Negroes. Femora of American Negro and White individuals with low ponderal indices were found to be less bowed than the norms for their race; individuals with high ponderal indices were more bowed than the norm for their race. The assumed genetic basis for expression of anterior femoral curvature suggested by Stewart ('62) and Walensky ('65) seems to be a feature of human plastic response to body weight rather than to temporal, clinal, postural or equestrian influences.     

Three-rooted mandibular first permanent molars and the question of American Indian origins

Three-rooted mandibular first molars (3RM1) are characteristic of Asian and Asian-derived populations, particularly Aleuts (whose 3RM1 frequency is the highest in the world) and Eskimos. Similarities in the frequency of these teeth between American Indians and contemporary peoples of southeastern Asia indicate a closer relation between these groups than between American Indians and Aleut-Eskimos. Three-rooted mandibular first molar frequency does not differ significantly in males and females except in Aleut-Eskimos. Bilateral asymmetry of 3RM1 is relatively frequent in both sexes and all groups. All American Indian groups examined have a low frequency of 3RM1 pointing to a single Asian origin, except Athabaskan-speaking Arizona Navajos, whose 3RM1 frequency approaches that of Aleut-Eskimos. There is no evidence at present of any significant local microevolution of 3RM1 in two testable prehistoric American Indian groups, although genetic drift had possibly occurred in a few series of 3RM1-deficient southwestern U. S. prehistoric Western Pueblo Indians. No adaptive value can be found for 3RM1 in Indians. In prehistoric western U. S. Indians geographic frequency variation is only slightly greater than the very slight (and non-significant) testable temporal variation. Three migrations from Asia seem best to explain New World 3RM1 frequency variation.     

Finger and palmar dermatoglyphics in Seminole Indians of Florida

Hand prints of 146 Florida Seminoles were obtained at the Brighton, Big Cypress and Dania reservations and at the Indian Agency in Dania. Comparisons with other tribes of North American Indians (Comanche, Arapahoe, Navaho, Hopi and Pueblo) reveal similarities with respect to fingerprint indices, frequencies of patterns in all palmar areas, and transverseness of palmar ridges. Comparisons of Seminoles and other North American tribes with the Mayans of southern Mexico and Guatamala show striking differences in pattern frequencies in the thenar/first interdigital area of the palm. Among North American Indians, the frequency varies from 18.49% among Seminoles to 28.5% among Navahoes, whereas all Mayan tribes which have been studied range between 40 and 50%. Pattern frequencies are higher in the thenar/first interdigital area than in the hypothenar area among all Amerindians who have been tested. This trend is the reverse of that found in other racial groups. North, Central and South American Indians are similar with respect to relatively high finger pattern indices, low frequencies of patterns in the hypothenar area, low frequencies of accessory triradii in the interdigital areas and moderately transverse palmar ridges.     

Aldehyde dehydrogenase polymorphism in North American, South American, and Mexican Indian populations.

While about 40% of the South American Indian populations (Atacameños, Mapuche, Shuara) were found to be deficient in aldehyde dehydrogenase isozyme I (ALDH2 or E2), preliminary investigations showed very low incidence of isozyme deficiency among North American natives (Sioux, Navajo) and Mexican Indians (mestizo). Possible implications of such trait differences on cross-cultural behavioral response to alcohol drinking are discussed.     

Brief communication: Population variation in human maxillary premolar accessory ridges (MxPAR)

The purpose of this brief communication is to report the results of an analysis of maxillary premolar accessory ridges (MxPAR), a common but understudied accessory ridge that may occur both mesial and distal to the central ridge of the buccal cusp of upper premolars. We developed a new five‐grade scoring plaque to better categorize MxPAR variation. Subsequently, we conducted a population analysis of MxPAR frequency in 749 dental casts of South African Indian, American Chinese, Alaskan Eskimo, Tohono O'odham (Papago), Akimel O'odham (Pima), Solomon Islander, South African Bantu, and both American and South African Whites. Northeast Asian and Asian‐derived populations exhibited the highest MxPAR frequencies while Indo‐European samples (South African Indians, American and South African Whites) exhibited relatively low frequencies. The Solomon Islanders and South African Bantu samples exhibited intermediate frequencies. Our analysis indicates that statistically significant differences in MxPAR frequency exist between major geographic populations. As a result, the MxPAR plaque has now been added to the Arizona State University Dental Anthropology System, an important contribution as maxillary premolar traits are underrepresented in analyses of dental morphology. Am J Phys Anthropol 2010. © 2009 Wiley‐Liss, Inc.     

Anthropometric studies in Brazilian Cayapo Indians

Results of 16 measurements and 7 indices obtained from 130 men and 156 women belonging to three populations of Brazilian Indians are reported. For both males and females the averages for stature and head breadth are in the middle of the distribution range of values observed in other South American tribes; those for head length and nasal height are relatively low but the averages for sitting height, calf circumference and minimum frontal breadth are high. As for the indices, in both sexes the cephalic and cephalofacial are medium, the Rohrer, jugomandibularis and facial low, and the nasal high when compared with other tribes. Morphological distances between the three Cayapo populations were estimated using Mahalanobis' D² statistic; they are smaller than those separating different tribes and are not the expected ones when the demographic variables of these groups and the geographic distances between them are considered. The amount of variability as expressed by the coefficient of variation and the prevailing pattern of sexual dimorphism are similar to those observed in other Indian populations.     

Injury mortality in New Mexico's American Indians,Hispanics, and non-Hispanic whites, 1958 to 1982.

New Mexico has extraordinarily high injury mortality rates. To better characterize the injury problem in New Mexico, we calculated proportionate injury mortality and age-adjusted and age-specific injury mortality rates for the state''s 3 major ethnic groups--American Indians, Hispanics, and non-Hispanic whites. According to death certificate data collected from 1958 to 1982 and US population census figures, age-adjusted mortality rates for total external causes varied widely between the sexes and among the ethnic groups. Males in each ethnic group consistently had higher average annual age-adjusted external mortality rates than females. Injury mortality rates for American Indians of both sexes were 2 to 3 times higher than those for the other New Mexico ethnic groups. Motor vehicle crashes were the leading cause of death from injury for all 3 groups. Homicide accounted for twice the proportion of injury death in Hispanic compared with non-Hispanic white males (12.5% and 6.1%, respectively), while the proportion of males dying of suicide was highest in non-Hispanic whites. Deaths from excessive cold and exposure were leading causes of injury mortality for American Indians, but these causes were not among the leading causes of injury mortality for Hispanics or non-Hispanic whites. We conclude that the minority populations in New Mexico are at high risk for injury-related death and that the major causes of injury mortality vary substantially in the state''s predominant ethnic populations.     

Immumoglobulin allotypes in Ecuadorian Cayapa Indians

Indigenous Indian groups comprise approximately 20% of Ecuador's population, the third largest percentage in all of Central or South America, yet immunogenetic data on these groups are lacking in the literature. In the course of population migration studies, sera collected from 65 Ecuadorians living in the northern province of Esmeraldas were typed for six GM and two KM markers. The study population consisted of 47 Cayapa Indians and 18 blacks of African origin, descendants of slaves imported into the area during the seventeenth century. The Cayapa demonstrated three GM phenotypes, two of which are common to other South American Indian tribes. The frequency of KM1 positive Cayapa Indians (63%) is similar to other South American Indian tribes, but is significantly greater than the Huaorani of eastern Ecuador (2%), the only other Ecuadorian Indian group for whom limited immunoglobulin allotype data are available ( ²=35.8, P<0.0001).     

Intra- and inter-tribal genetic variability in South American Indians

A review was made of all studies to date concerning the genetic polymorphisms of South American Indians. The observed inter-tribal variability was then compared with the intra-tribal variation encountered in seven Caingang and three Xavante Indian communities. The differing pattern of genetic variability observed within these two tribes was afterwards correlated with the information available about their breeding structure.     

Hydrogen cyanide and phenylthiocarbamide sensitivity, mid-phalangeal hair and color blindness in Yucatán, Mexico

Approximately 1450 persons, 800 of them unrelated, of both sexes from age eigth upward from the town of Ticul, Yucatán, Mexico, formed an American Indian (Maya) sample with apparently little Caucasian admixture for four genetic tests: ability to taste PTC and smell HCN, presence of mid-phalangeal hair, and color blindness. A modified PTC sorting test indicated a nontaster allele (t) frequency of 0.29 in Ticul, a relatively high result for American Indians but compatible with previously reported Mayan data. A color vision deficiency frequency of 3.6% was found in the total male sample, and a subsample of unrelated males had a rate of 2.8%. No color blind females were detected. The Ticuleños exhibited a high rate of midphalangeal hairlessness, characteristic of American Indians, with a notable sex differential: 75.9% for males, 87.1% for females. Previous studies of the inability to smell HCN, most of which suggest an X-linked recessive inheritance with an allele frequency of about 0.2, are reviewed. The Yucatán material, with a nonsmeller prevalence around 50% and no significant difference between the sexes, contradicts the X-linked recessive hypothesis on the basis of both population and family analyses. No simple Mendelian scheme appears to fit the Ticul HCN sensitivity test results.     

Some genetic traits in Solomon Island populations. IV. Mid-phalangeal hair

Among 425 Lau and 467 Baegu of northern Malaita, there were no tribal differences in mid-phalangeal hair. The trait was present more often in males than in females, and after puberty than before it. Age differences were more marked for males than for females. Among 168 men 20 years of age and older in both tribes, the frequency of mid-phalangeal hair was 58.3%; among 189 women of similar age, 34.4%. These frequencies were at or just below those reported for Caucasian samples, just above that for Japanese, and considerably above those for Negroes and American Indians. Analysis of family data did not confirm the hypothesis that the absence of mid-phalangeal hair is recessive to its presence.     

Phenice's visual sexing technique for the os pubis: a critique

Innominate bones from 362 California Indians were sexed with Phenice's three non-metrical features of the os pubis. The frequencies of marked, intermediate, and absent cases of these three morphological features were tabulated in males and females to see if unambiguous and reliable distinctions were consistently available. The results suggest that Phenice's technique offered extremely reliable sex evaluations in this material.     

Finger dermatoglyphics of the Peruvian Cashinahua

The Peruvian Cashinahua are an isolate of unmixed American Indians living in four villages in the Southeastern part of the country. Finger dermatoglyphic data were collected from the three most closely grouped villages in the summer of 1966. The relatively low proportion of whorls and high proportion of arches, and the low values of pattern intensity (10.75) and total ridge count (89.14) contrasts markedly with other American Indian groups in general, and with Amazon Basin groups in particular. The distinctive finger print patterns may be explained by factors such as genetic drift and inbreeding, which can alter gene and phenotype frequencies in small populations.     

MICA polymorphism in South American Indians

We have studied the MICA alleles of 196 unrelated subjects from three South American Indian tribes (Toba, Wichi and Terena). They are members of isolated tribes located in the Gran Chaco area in northeastern Argentina and in Mato Grosso do Sul in South Central Brazil. Of 55 previously known alleles, nine were observed in South American Indians, compared with 16 that were found in North American Caucasians, suggesting a more restricted allelic distribution of MICA in these tribes. In South American Indians, MICA*00201 was the most frequent allele, with a gene frequency of 33% in Toba, 47% in Wichi and 44% in Terena. MICA*00201, MICA*027 (external domain sequence like MICA*008/TM allele A5) and MICA*010 accounted for more than 90% of all the MICA genes in South American Indians. In North American Caucasians, MICA*00801 (*008/A5.1) accounted for 42% of the genes and was the most common allele. We observed a high degree of linkage disequilibrium between certain alleles of MICA and of HLA-B in the South American Indian populations. Phylogenetic trees constructed using gene frequencies of the transmembrane short tandem repeats in the populations reported here, and in other populations taken from published reports, suggest that South American Indians are more closely related to Asians than to Europeans.     

Ethnic differences in mortality from acute rheumatic fever and chronic rheumatic heart disease in New Mexico, 1958-1982.

To examine time trends and differences in mortality rates from acute rheumatic fever and chronic rheumatic heart disease in New Mexico''s Hispanic, American Indian, and non-Hispanic white populations, we analyzed vital records data for 1958 through 1982. Age-adjusted mortality rates for acute rheumatic fever were low and showed no consistent temporal trends among the three ethnic groups over the study period. Age-adjusted and age-specific mortality rates for chronic rheumatic heart disease in Hispanic and non-Hispanic whites decreased over the 25-year period, although rates were higher among Hispanics than among non-Hispanics during most of the time period. In American Indians, age-adjusted mortality rates for chronic rheumatic heart disease increased between 1968 and 1977 to twice the non-Indian mortality rates during the same period. Despite this increase in mortality from chronic rheumatic heart disease among New Mexico''s American Indians from 1968 to 1977, the New Mexico data generally reflect national trends of decreasing mortality from chronic rheumatic heart disease.     

Tooth size of Ticuna Indians,Colombia, with phenetic comparisons to other Amerindian

This study reports on odontometric analyses of unadmixed, adult Ticuna Indians, Colombia, South America. This group is characterized by crown diameters intermediate in size relative to the known Amerindian range and, in turn, to the range in modern man. Sex dimorphism is absent in Ticuna tooth size; there is a strong retention of the M1 > M2 size sequence. The Ticuna are compared multivariately to other Indian groups reported in the literature, using the size and shape coefficients of L.S. Penrose. Tooth size clusters the groups into small, medium, and large-toothed classes, but does not yield a pattern attributable to known genetic or historical affinities. Shape coefficients distinguish Indians from non-Indians (Caucasian, Negroid, and Australian samples), primarily on the basis of I1–I2 proportionalities. Neither size nor shape discriminates between North and South American groups.     

Normative genetic profiles of RAAS pathway gene polymorphisms in North Indian and South Indian populations

Population-based genetic association studies, popularly known as case-control studies, have continued to be the most preferred method for deciphering the genetic basis of various complex diseases, even in the post-human genome sequencing era. However, interpopulation differences in allele, genotype, and haplotype frequencies and linkage disequilibrium patterns lead to inconsistent results in candidate gene association studies. Therefore, for any meaningful disease association study, knowledge of the normative genetic background of the baseline population is a prerequisite. In addition, such genetic variation data also provide a ready-made menu of allele frequencies and linkage disequilibrium patterns of various polymorphisms in specific candidate genes in a particular population, which is a useful reference for further genetic association studies. Such genetic variation data are lacking for the Indian population, which represents about one-sixth of the world's population. In the present study we have reported the allele, genotype, and haplotype frequencies, Hardy-Weinberg equilibrium status, and linkage disequilibrium patterns of 12 polymorphisms in six candidate genes from the renin-angiotensin-aldosterone system among Indians. Because of their different history of origin, the Indian population is broadly divided into two subpopulations: North Indians (Caucasian Europeans) and South Indians (Dravidians). Considering this well-documented difference in gene pools, we have presented a comparative account of the normative genetic data of North Indian and South Indian populations with at least four individuals of urban and suburban origin from each of the representative states of northern and southern India.     

The genetic structure of a tribal population, the Yanomama Indians XI. Gene frequencies for 10 blood groups and the ABH-Le secretor traits in the Yanomama and their neighbors; the uniqueness of the tribe.

In this paper we present the results of blood group typings for a total of 33 villages distributed among five South American Indian tribes--Yanomama (21 villages), Makiritare (eight villages), Macushi (two villages), Piaroa (one village), and Wapishana (one village). These new results for the Yanomama and Makiritare tribes have been combined with those previously reported to allow a better appreciation of the distribution of allelic frequencies in the tribes. The relationship of the Yanomama to other South American Indian tribes is investigated using data on six polymorphic loci (Rh, MNS, Fy, Jk, Di, Hp). By use of four genetic measures (two of genetic relationship and two of genetic diversity), we demonstrate that the Yanomama are genetically unique among a sample of 20 South American tribes. In addition, the Yanomama show somewhat less genetic diversity for the six loci analyzed than the average South American tribe. Taken together, these results indicate a rather long period of isolation for the population antecedent to the Yanomama--perhaps since the time of entry of man into the South American continent. The pattern of genetic relationships and genetic diversity for the 20 tribes is consistent with the hypothesis that evolution in South America proceeded by a process of fission-fusion leading to isolation of subpopulations with subsequent genetic differentiation as a consequence of population isolation. The uniqueness of the Yanomama appears to stem entirely from such a process, there being no evidence of any selective differential for the loci analyzed.