P.T.C. thresholds, blood factors, colour vision and fingerprints of Jivaro Indians in Eastern Ecuador

Among the Jivaro Indians of Eastern Ecuador, very low non-taster frequencies were found, a situation in accord with most of the other, through few sets of P. T. C. data available for South American Indians. The Jivaro have maximal frequencies (1.000) of the alleles I° and D, typical of most South American Indian groups. The colour blindness frequency of males (7.1%) is seemingly higher than North American Indian figures and is similar to European frequencies. Jivaro dermatoglyphic data are in broad general agreement with data available for Amerindian groups generally, and for many Asian mongoloids, with high pattern intensity indices for males and females, mainly the result of a very high whorl incidence. The digital distribution of the pattern types for the greater part accords with the generalisations of Cummins and Midlo ('61). There are marked sex differences in the data, females having a lower mean pattern intensity index, a higher value for Dankmeijer's Index and a lower value for Furuhata's Index. Unfortunately there are few other sets of South American Indian data available for comparative purposes.     

Variability of the F13B locus in South American populations

A population study for the F13B locus was carried out in a total of 396 South American individuals. The analysis comprised new data from 5 Amerindian populations, existing data from 3 Amerindian populations, and I urban sample from La Plata, Argentina. In both pooled Amerindian and La Plata samples, 6 alleles were found. The individual Amerindian samples showed a lower number of alleles, changes in modal alleles, and restricted variability. Interpopulation comparisons revealed significant differences among samples from distinct geographical regions. Differences among the groups were also corroborated by the F(ST) statistic. Data support the hypothesis that genetic drift and gene flow influence Amerindian differentiation.     

Child growth and adult physique in Brazillan Xingu Indians

Data on stature, sitting height, biacromial width, and some other body measurements on 267 children and 363 adults of the Xingu Indians of Brazil have been analyzed. Adult height shows no significant decrease with age over an age range of 20–50 years, thus indicating the absence of secular changes. The average Xingu child seems to be around the twenty-fifth to fiftieth centile for height of British children (if our age estimates are correct) until about ten years in girls and 14 years in boys, but ends at below the third British centile as an adult. In sitting height, however, the Indians show substantially lower values, with children being at about the fifteenth centile until ten years in girls and 14 years in boys, while the adults are considerably below the British third centile. Other comparisons show that the Xingu are taller than Surinam Indians although of similar shoulder width. The lack of anthropometric data concerning South American Indian adults, and more especially children has been stressed. Investigations of these populations facing rapid acculturation and possible assimilation will form a baseline for the future work in public health as contacts with non-Indians increase.     

Age differences in craniofacial dimensions among adults from Indian Knoll,Kentucky

Adult craniofacial expansion with aging has recently been documented in a living US white population sample (Israel, '73a, '77). The present study extends these findings to a prehistoric Amerindian skeletal sample from the Indian Knoll, Kentucky site. Sixteen craniofacial dimensions available for 136 adult males were compared in younger (20–34 years) and older (35–50 years) age groups. Of these, six dimensions showed a significant difference between age groups; all significantly different dimensions were larger in the older adult age group. The multivariate (T²) difference between age groups was highly significant. Comparison of results before and after a size standardization indicated that the majority of differences between age groups were associated with an overall size increase, or expansion with aging, and did not represent merely remodeling, or “shape” changes. The pattern of craniofacial change with age appeared generally similar to that observed in the modern US white sample; however, some differences were noted. It is shown that the age trends observed at Indian Knoll are most likely to reflect true craniofacial growth in size among the adult male inhabitants of the site, rather than secular trends or other artifacts of the sampling procedure. The causes for continuing adult craniofacial expansion are unknown, and probably involve a complex interaction of many factors. However, this pattern of change with age among adults does appear to be characteristic of population samples of widely differing genetic and environmental backgrounds.     

American Indian Population Recovery following Smallpox Epidemics

Scholars generally agree that American Indian populations were reduced substantially following European contact by a variety of Old World diseases. However, scholarly attention has been devoted almost exclusively to ascertaining mortality during smallpox and other disease episodes and its impact on population size, as typified in "working backwards" to ascertain earlier population size. American Indian populations were dynamic entities, and were constantly changing as members were born, died, or migrated, even if population size from one year to the next was relatively constant. The interaction of disease, mortality, and fertility as well as the age structure of mortality and resulting rates of population growth influenced changes in American Indian population size following experiences with any particular disease. These factors operated to produce either greater or lesser declines than simple mortality rates would suggest. This article presents simulations developed to understand changes in American Indian population size following hypothetical episodes of smallpox.     

Quantitative trait analysis and geographic variability of natural populations of Zaprionus indianus, a recent invader in Brazil

Five natural samples of a recent South America invader, the drosophilid Zaprionus indianus, were investigated with the isofemale line technique. These samples were compared to five African mainland populations, investigated with the same method. The results were also compared to data obtained on mass cultures of other populations from Africa and India. Three quantitative traits were measured on both sexes, wing and thorax length and sternopleural bristle number. We did not find any latitudinal trend among the American samples, while a significant increase in body size with latitude was observed in the Indian and, to a lesser degree, in the African populations. American populations were also characterized by their bigger size. Genetic variability, estimated by the intraclass correlation among isofemale lines, was similar in American and African populations. The intraline, nongenetic variability was significantly less in the American samples, suggesting a better developmental stability, the origin of which is unclear. A positive relationship was evident between intraline variability of size traits and the wing-thorax length correlation. Altogether, our data suggest that the colonizing propagule introduced to Brazil had a fairly large size, preventing any bottleneck effect being detected. The big body size of American flies suggests that they came from a high-latitude African country. The lack of a latitudinal dine in America seems to be related to the short time elapsed since introduction. The very rapid spread of Z. indianus all over South America suggests that it might rapidly invade North America.     

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.     

Maternal mortality or prolonged growth: Age at death and pelvic size in three prehistoric Amerindian populations

This study evaluates the relationship between age at death and pelvic size among adults in three prehistoric Amerindian populations. The issue is to identify if the pelvis continues to grow and remodel in adulthood, or if there is differential survivorship among adults, particularly among females, based on pelvic size. The samples used in this study are Indian Knoll, Pecos Pueblo, and Libben. Twenty-one measures of the pelvis are analyzed. A correlational analysis among individuals 18 years of age and older shows that the subpubic angle narrows with advancing age in both sexes. The suggested etiology is osteophytic growth on the ischiopubic ramus among older adults. A two-sample test comparing younger (ages 18–24) and older (25 years of age and older) adults shows that the linea terminalis (which represents the pubic and iliac components of the pelvic inlet) is significantly shorter in the younger age group, but this pattern is seen only in females. Two interpretations are consistent with this result. First, a female with a short linea terminalis (i. e., small pelvic inlet) may have died at a young age due to childbirth-related complications. In prehistory, maternal mortality may have been a leading cause of death, with pelvic inlet capacity being a determinant of survivorship among parturients. Second, the linea terminalis may be unique by continuing to grow in early adulthood in females but not in males; the growth occurs at the medial border of the pubis. Longitudinal growth studies of modern humans provide support for the second interpretation. The selective advantage of a later age at maturation of the pubis in females than males is that the period of growth is prolonged, thereby contributing to sexual dimorphism in pubic length and, correspondingly, linea terminalis length and pelvic inlet circumference. © 1994 Wiley-Liss, Inc.     

Body height,weight, and skeletal maturation in Hottentot (Khoikhoi) children

Growth of body height and weight and skeletal maturation are discussed, based on 49 male and 61 female Hottentot children aged 3 to 17 years from Warmbad, Namibia (South West Africa) and 124 boys and 113 girls aged 1 to 21 years of related populations, the Rehoboth Basters of Namibia and Cape Coloreds from Cape Town, South Africa. The related populations are taller and heavier than the Hottentots, and have almost the same body height as American blacks and whites at least after the age of 18 years. In the Hottentots and Rehoboth Basters, the mean TW2 skeletal age is always less than the British standard by one or two years in both sexes. In general, the Rehoboth Basters have a skeletal age that is intermediate between Hottentot and British children. In both Hottentots and Rehoboth Basters, the increase in body height shows a linear relation to the skeletal age, and the regression curves are almost parallel in both sexes. The differences in body height and weight between the Hottentots and Rehoboth Basters become greater after the skeletal ages of 15 years for boys and 13 years for girls.     

Indeterminate growth in long-lived freshwater turtles as a component of individual fitness

Although evidence that reptiles exhibit indeterminate growth remains equivocal and based on inadequate data, the assumption that they do is still widely accepted as a general trait of reptiles. We examined patterns of variation in adult growth using long-term mark-recapture data on 13 populations of 9 species representing 3 families of freshwater turtles located in South Carolina, Michigan, and Arizona in the USA and in Ontario, Canada. Across 13 study populations, growth rates of all adults and only those that grew averaged 1.5 and 1.9 mm/yr respectively. Sources of variation in growth rates included species, population, sex, age, and latitude. Most adults of both sexes with recapture intervals greater than 10 years grew, but across all populations an average of 19 % of individuals did not grow (some with recapture intervals up to 30 years). For known-age adults of three species, the highest growth rates occurred during the 10 years following sexual maturity, and the proportions of non-growing individuals increased with age. Growth rates of adults were on average 92 % lower than those of juveniles. Based on linear relationships of clutch size and body size of females at average juvenile and adult growth rates it would take 0.7 (0.2–1.2) years and 8.6 (min–max = 2.3–18.5) years, respectively, to grow enough to increase clutch size by one egg. The majority of within population variation in adult body size in 3 species appeared to be a combination of differences in ages at maturity and juvenile and early adult growth, rather than indeterminate growth. The results from our study populations indicate that increases in body size (and associated reproductive output) that results from indeterminate growth are not substantial enough to represent a major factor in the evolution of life histories in general or the evolution of longevity and aging specifically.     

Morphological variation of introduced species: The case of American mink (Neovison vison) in Spain

We studied the morphology of American mink Neovison vison in five out of the six introduced populations in Spain. The spatial and temporal variation of body weight (BW), body length (BL), tail length, hind-foot length and ear length were analysed. Temporal trends in BW and BL in relation to years since mink introduction were also analyzed. In addition, we tested the effect of sex, age (juvenile, subadult and adult) and age–sex interaction, on each parameter. Morphological parameters differed between populations, illustrating the high variability of body size of American mink in different environments, and the phenotypic plasticity of the species. Annual variations were synchronized between populations, suggesting a large-scale effect on all of them. BW and BL showed a decreasing trend in both males and females in relation to years since introduction. This decrease may be related to mink's diet. Differences in sex and age were found, pointing to sexual dimorphism in adults, subadults and juveniles. The dimorphism in non-adult individuals suggests that subadult males may have a competitive advantage from subadult females in feeding and/or hunting on bigger prey from an early age (resource partitioning hypothesis).     

Cystic fibrosis gene variability in two southern Brazilian Amerindian populations: analysis of the deltaF508 mutation and the KM19 and XV2C haplotypes

The frequencies of the deltaF508 deletion, the most common cystic fibrosis mutation in Europeans and European-derived populations, and the XV2C and KM19 restriction fragment length polymorphisms that are tightly linked to the CFTR locus vary among populations. To determine the distribution of these extragenic markers and of the deltaF508 mutation, we analyzed 326 chromosomes of individuals from two South American Indian populations, the Guarani and the Kaingang. The allele and haplotype frequencies differed greatly between the two populations as well as among Amerindians and normal European Brazilians and European Brazilian cystic fibrosis patients. The absence of the deltaF508 mutation and the B haplotype are in agreement with the hypothesis that the deltaF508 mutation occurred after the divergence of these two populations. This finding is useful for populations containing a large Amerindian component and helps us to understand the origins of the deltaF508 deletion, the most common cystic fibrosis mutation in Europeans and European-derived populations, as well as the different incidences of cystic fibrosis in continental groups.     

Genetic diversity of two African and sixteen South American populations determined on the basis of six hypervariable loci

A total of 582 individuals (1,164 chromosomes) from two African, eight African-derived South American, five South American Amerindian, and three Brazilian urban populations were studied at four variable number of tandem repeat (VNTR) and two short tandem repeat (STR) hypervariable loci. These two sets of loci did not show distinct allele profiles, which might be expected if different processes promoted their molecular differentiation. The two African groups showed little difference between them, and their intrapopulational variation was similar to those obtained in the African-derived South American communities. The latter showed different degrees of interpopulation variability, despite the fact that they presented almost identical average degrees of non-African admixture. The F_ST single locus estimates differed in the five sets of populations, probably due to genetic drift, indicating the need to consider population structure in the evaluation of their total variability. A high interpopulational diversity was found among Amerindian populations in relation to Brazilian African-derived isolated communities. This is probably a consequence of the differences in the patterns of gene flow and genetic drift that each of these semi-isolated groups experienced. Am J Phys Anthropol 109:425–437, 1999. © 1999 Wiley-Liss, Inc.     

Ontogenetic plasticity in nonhuman primates: I. Secular trends in the Cayo Santiago macaques

Although secular trends toward increasing body size are apparent in many human populations, little is known about their occurrence in nonhuman primates. The Cayo Santiago skeletal collection of Macaca mulatta includes 101 adult animals (greater than or equal to 10 years of age) born at different times in the past 3 1/2 decades, so that variation in size may be examined relative to birth year. No secular trends in orbital height were observed in this sample, but in both sexes lengths of adult long bones increased significantly over time, while cranial dimensions and length of the second molar in female also showed significant variation with birth year. These changes were consistent with the history of provisioning of the animals and with fluctuations in population size. Low-order correlations were observed between birth year and body proportions, especially the crural index in males, a pattern that has also been observed in human populations. These findings argue that, in addition to biomechanics and heritage, diet may affect allometric relationships and that an inherent plasticity or malleability of the growth process may be characteristic of nonhuman as well as human primates.     

Variation in number of ventral scales in snakes: effects on body size, growth rate and survival in the adder, Vipera berus

The relationship between number of ventral scales, correlating with number of body vertebrae, and body size of adders, Vipera berus , was investigated using captive-born young and wild-caught adults (snout-vent length > 400 mm) from six populations in eastern Sweden. Females had significantly more ventral scales, and were larger, than males in all populations. Among adult individuals, snout-vent length was highly positively correlated with the number of ventral scales when differences due to sex and locality were controlled for. The same pattern was true for newborn individuals when differences due to litter and sex were controlled for. The influence of number of ventral scales on survival and growth rate as possible causes of this positive correlation was examined. Mean number of ventral scales was lower in new-born snakes than in adults, indicating selection against individuals with a low scale count. Since this selection appears to take place in the early juvenile phase, it is inadequate to explain the relationship between adult body size and number of ventral scales. However, individuals with many ventral scales had significantly higher growth rates than individuals with few ventrals. This suggests that individuals with many ventral scales enjoy a higher growth rate and therefore are able to reach a larger size than their conspecifics of the same age with few ventral scales. This would explain the positive relationship between body size and ventral scale number observed in new-born and adult snakes.     

Different cell size and cell number contribution in two newly established and one ancient body size cline of Drosophila subobscura

Latitudinal genetic clines in body size occur in many ectotherms including Drosophila species. In the wing of D. melanogaster, these clines are generally based on latitudinal variation in cell number. In contrast, differences in wing area that evolve by thermal selection in the laboratory are in general based on cell size. To investigate possible reasons for the different cellular bases of these two types of evolutionary response, we compared the newly established North and South American wing size clines of Drosophila subobscura. The new clines are based on latitudinal variation in cell area in North America and cell number in South America. The ancestral European cline is also based on latitudinal variation in cell number. The difference in the cellular basis of wing size variation in the American clines, which are roughly the same age, together with the similar cellular basis of the new South American cline and the ancient European one, suggest that the antiquity of a cline does not explain its cellular basis. Furthermore, the results indicate that wing size as a whole, rather than its cellular basis, is under selection. The different cellular bases of different size clines are most likely explained either entirely by chance or by different patterns of genetic variance--or its expression--in founding populations.     

The Brazilian Xavante Indians revisited: New protein genetic studies

A total of 94 individuals from the Xavante village of Rio das Mortes were variously studied in relation to 28 protein genetic systems. No variation was observed for 15 of them, in accordance with previous studies. Of the remaining 13, four (Rh, Duffy, acid phosphatase, and GC) showed significant departures from the averages obtained in 32 other South American Indian populations. If studies performed in the 1960s are considered, there is indication that no significant changes in this village's gene pool has occurred in the last 30 years. Comparison with two other Xavante populations included nine systems with variation, and for three of them (MNSs, Rh, and Duffy) significant differences were found. Genetically the Rio das Mortes are closer to the São Marcos than to the Simões Lopes Xavantes. A dendrogram considering 25 genetic systems and 33 South American Indian populations was constructed. There the Xavante were grouped together, in two neighboring clusters, with three other tribes who speak Ge languages. But these clusters also present populations who speak other languages, and the reproducibility of the tree is low. South American Indians, at least with this set of markers, do not seem to be clearly classified into defined subgroups. Am J Phys Anthropol 104:23–34, 1997. © 1997 Wiley-Liss, Inc.     

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.     

Possible migration routes into South America deduced from mitochondrial DNA studies in Colombian Amerindian populations

Mitochondrial DNA haplotype studies have been useful in unraveling the origins of Native Americans. Such studies are based on restriction site and intergenic deletion/insertion polymorphisms, which define four main haplotype groups common to Asian and American populations. Several studies have characterized these lineages in North, Central, and South American Amerindian, as well as Na Dene and Aleutian populations. Siberian, Central Asian, and Southeast Asian populations have also been analyzed, in the hope of fully depicting the route(s) of migration between Asia and America. Colombia, a key route of migration between North and South America, has until now not been studied. To resolve the current lack of information about Colombian Amerindian populations, we have investigated the presence of the founder haplogroups in 25 different ethnic groups from all over the country. The present research is part of an interdisciplinary program, Expedición Humana, fostered by the Universidad Javeriana and Dr. J. E. Bernal V. The results show the presence of the four founder A-D Amerindian lineages, with varied distributions in the different populations, as well as the presence of other haplotypes in frequencies ranging from 3% to 26%. These include some unique or private polymorphisms, and also indicate the probable presence of other Asian and a few non-Amerindian lineages. A spatial structure is apparent for haplogroups A and D, and to a lesser extent for haplogroup C. While haplogroup A and D frequencies in Colombian populations from the northwestern side of the Andes resemble those seen in Central American Amerindians more than those seen in South American populations, their frequencies on the southeastern side more closely resemble the bulk of South American frequencies so far reported, raising the question as to whether they reflect more than one migration route into South America. High frequencies of the B lineage are also characteristic of some populations. Our observations may be explained by historical events during the pre-Columbian dispersion of the first settlers and, later, by disruptions caused by the European colonization.     

Tooth crown size differences between age groups: A possible new indicator of stress in skeletal samples

Juveniles and adults from a prehistoric Amerindian skeletal series from Tennessee are compared for differences in the means and variances of the buccolingual dimensions of their permanent teeth. While there are no significant differences in variance, it is found that juveniles exhibit significantly smaller mandibular canines, first premolars, and first molars. The results are similar to those of a previous examination of an Amerindian skeletal collection from South Dakota. There is evidence to suggest that teeth may fail to develop to their maximum genetic size potential when there is interference from exogenous chronic stressors such as malnutrition or disease. Archeological and biological evidence demonstrates that both the Tennessee and South Dakota series represent groups that suffered considerably from environmental stressors. It is suggested that those persons who suffered most were more likely to die prematurely, thus explaining why juvenile skeletons tend to have smaller teeth. The conclusion is that the examination of age variation in crown size can be a useful supplement to other osteological indicators of stress in skeletal collections. The factor of sex ratio and the implications of the results for other kinds of dental metric studies are discussed.