The number of vertebrae in the Southern African Negro,the American Negro and the Bushman (San)

The numbers of precoccygeal vertebrae (PCV) are compared in Southern African Negroes, Bushman (San) and American Negroes. The S.A. Negro and San males have an exceptionally high frequency of an increased total PCV number whilst the frequencies are significantly lower in a combined Caucasoid sample and the Mongoloid samples. The American Negro male, too, has a high frequency but not as high as in S.A. Negroes. The high frequency of increased PCV number in San, S.A. Negroes and American Negroes is in keeping with the view that the Khoisan peoples (here represented by the San), the Southern African Negroes and the African ancestors of American Blacks sprang from a common proto-negriform stock. Males have a significantly greater frequency of increased PCV to 30 or 31, whereas females are more likely to have a decreased number of 28 PCV. This sex difference is present in all the populations studied.     

Numerical variation of the presacral vertebral column in three population groups in North America

A total of 1,239 skeletons from among Mongoloid, Caucasoid and Negroid population groups in North America was examined for variations in the number of presacral vertebrae. The overall incidence of variation was 11%; 6% with 23 and 5% with 25 presacral vertebrae. Differences in total variation among the three groups were not significant, but differences in the incidence of 23 and 25 presacral vertebrae among the groups were highly significant. Numerical vertebral variation occurred in 11% of both sexes, but with males having a higher frequency of 25 presacral vertebrae and females having a higher frequency of 23 presacral vertebrae. The incidence of the specific variation of 23 or 25 presacral vertebrae was not significantly different among the males of the three groups studied, whereas 23 presacral vertebrae were found significantly more often in the Negroid females. Numerical variation of vertebrae was not associated with age. The data strongly support the conclusion that the total frequency of variation in the number of presacral vertebrae is a specific characteristic of any particular population group and that there is a tendency in all population groups toward an increase in number in males and a decrease in number in females.     

Notches in the non-epiphyseal ends of the metacarpals and phalanges in children of four South African populations

The incidence of notches in the non-epiphyseal ends of the shafts of the metacarpals and phalanges was determined from radiographs of the left hand of 1,303 Pretoria school-children aged 6 to 11 years. The group included White, Negro, Coloured and Indian children. The notches represent vestiges of supernumerary epiphyses or pseudo-epiphyses. Notching of one or more of the metacarpals or phalanges was found in 88.9% of White children, 77.1% of Negro children, 84.3% of Coloured children and 78.8% of Indian children. Notches were most common in metacarpal I followed in declining order of frequency by metacarpal II, metacarpal V, middle phalanx V and proximal phalanx I. Notches were rare in other sites. The mean number of notches per subject was significantly higher in males than in females in all four population groups. However, the sex differences appear to be due mainly to earlier obliteration of notches in females. The findings in White children suggest that there is no significant relationship between metacarpal and phalangeal notching and skeletal maturation rate. Notches are significantly more common in Pretoria Whites than in relatively poorly nourished Pretoria Negro children. It is concluded that the occurrence of notches is a normal phenomenon accompanying the ossification of the hand skeleton and that notching is related neither to retardation in skeletal development nor to undernutrition.     

Frequency-dependent numerical dynamics in mosquitofish

Altering the genetic composition of a population can alter several aspects of its numerical dynamics. Whether natural populations routinely contain the genetic variation capable of affecting the stability of those dynamics is less clear. Here we report a study of experimental populations of mosquitofish (Gambusia holbrooki), designed to examine this issue. The experiment examined the numerical effects of varying the initial relative frequency of a rare male genotype. A higher relative frequency of the rare, melanic genotype produced higher mortality rates in melanic males, higher mortality rates in females, higher juvenile abundance, and fewer fluctuations in the numbers of females across time. This work demonstrates that a natural population can harbour genetic variants in a single gender that are capable of inducing qualitative differences in the numerical dynamics of the opposite gender, through the effects of negative frequency-dependent selection.     

Sex and race differences in finger ridge-count correlations

Correlations between ridge-counts on the ten fingers were compared by race and sex in 11 samples representing Negroes and Caucasians: five from subsaharan Africa, one American Black, three European, one American White and one from India. The samples of European ancestry showed no consistent sex difference in mean correlation, although female American Whites significantly exceeded males. In three of the six Negro samples and in the Parsis of India males showed significantly higher average correlations than females. The pattern of sex and race differences suggests that the sex chromosomes, particularly the Y chromosome, play a role in dermal ridge development.     

Carpal fusions in children of four South African populations

The incidence of carpal fusions was determined from radiographs of both hands of 2,250 Pretoria schoolchildren aged 72 to 191 months. The group included White, Negro, Coloured and Indian subjects. Of the many possible varieties of carpal fusion, only lunato-triquetral fusion and capitate-hamate fusion were encountered. No examples of lunato-triquetral fusion were encountered in children less than ten years of age. In Pretoria Negroes aged 10 to 15 years, the incidence of lunato-triquetral synostosis is 4.57%, while Pretoria Coloureds show an incidence of 1.51%. This type of fusion was not noted in the White or Indian populations. Two examples of capitate-hamate synostosis were encountered in Pretoria Negroes. The available evidence suggests that these two varieties of carpal fusion may be added to the list of discrete traits varying in frequency from population to population and probably reflecting different underlying gene frequencies. No significant sex difference in incidence of lunato-triquetral fusion was noted in the present study. Lunato-triquetral fusion is about twice as commonly bilateral as unilateral in occurrence.     

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.     

Glyoxalase I polymorphism and racial admixture in the Cuban population

Summary The polymorphism of glyoxalase I (GLO I) was demonstrated in the three main racial groups (Caucasian, Mulattoes, and Negroes) of the Cuban population. The GLO I gene frequencies were used to estimate the relative contribution of Negro and Caucasian genes to the genetic makeup of these three groups.Banco de Sangre Provincial     

Digital and palmar dermatoglyphs of South African Whites.

Digital and palmar dermatoglyphs in a random sample of normal Whites from Durban are described. The sample consisted of 200 males and 200 females. Features examined included frequency and distribution of finger patterns, digital and total ridge count, a-b score, and palmar topography. Data from this study are compared to similar data from South African Negroes, Indians, and Coloureds (mixed racial origin) and several outstanding racial characteristics are demonstrated in the dermatoglyphic profiles. It is suggested that the Indians' dermatoglyphic profile is dominant to those of Whites and Negroes.     

Allocation and discrimination based on human odontometric data

This study contrasts the confidence with which individuals may be grouped and then re-allocated on the basis of odontometric data. These data are derived from the mesiodistal and buccolingual diameters of 202 Lengua Indians of Paraguay (100 males, 102 females), 125 Caucasoid schoolchildren (59 male, 66 female), and 206 Negroes (106 male, 100 female). Multivariate intergroup discrimination is effected by means of canonical and stepwise discriminant analysis, whilst allocation is evaluated by means of posterior and typicality probabilities. Bias is reduced by means of a jackknifing procedure. High levels of discriminatory confidence (each Wilk's Lambda, P less than 0.01) are matched by high percentage correct classification (Caucasoid, 67.4-75.0%; Negro, 71.0-77.3%; Amerindian, 65.2-78.1%). However, these results are not matched by allocatory procedures: only 21.7% of caucasoids, 21.4% of Negroes, and 28.8% of Amerindians could be re-allocated with probabilities in excess of 80%. It is concluded that while multivariate discriminant techniques may be usefully employed in the separation of different populations, individuals may not be assigned with the same degree of confidence, even with an a priori knowledge of their group membership.     

The plasminogen polymorphism in South African Negro populations: genetics and anthropogenetics

Summary Genetic polymorphism of human plasminogen (PLG) was investigated in 1252 unrelated individuals from eight South African Bantu-speaking Negro tribes. PLG phenotypes were determined by isoelectric focusing (pH 3.5–9.5 and 5–8 gradients) of neuraminidase-treated samples and subsequent detection by caseinolytic overlay or immunoblotting with specific antibody. No significant difference in the distribution of PLG alleles among the eight ethnic groups was observed. The combined allele frequencies of the common alleles in South African Negroes were 0.6977 for PLG*A, 0.2736 for PLG*B. In addition, six rare alleles were seen: PLG*A3, *A1, *M2, *B1, *B2, *B3. The rare variant PLG*B2 was proven to segregate by autosomal Mendelian inheritance in a family. The combined frequency for the rare alleles was 0.0287. The distribution of phenotypes in the total population sample was found to be in Hardy-Weinberg equilibrium. A striking difference in PLG allele distribution between Negroes from South Africa and published Negroid frequencies from North America could be observed. This difference was also seen in comparison with Mongoloid populations; in contrast, PLG frequencies for South African Negroes were similar or almost identical to known Caucasoid distributions.     

Fingerprints of Whites and Negroes from Southern Brazil

Studies on 1,115 individuals (451 Whites, 240 Light Mulattoes, 236 Dark Mulattoes and 188 Negroes) from Pôrto Alegre, Brazil are reported. The differences among those subgroups are not large and there is not a clear gradient when we consider samples with increasing Negro ancestry. The most marked difference between Whites and the total Negroid group occurred in the prevalence of radial loops. Comparison with Portuguese and African series indicates that no single factor can fully explain the observed distributions. But the values of Dankmeijer's index are exactly those expected on the assumption of 50% White admixture in the Pôrto Alegre Negro, in agreement with previous investigations.     

Erythrocyte glucose-6-phosphate dehydrogenase in the Niokolonko (Malinke of the Niokolo) of Eastern Senegal. Identification of a slow variant with normal activity (Tacoma-like).

In a survey of blood genetic markers in the Niokolonko of Eastern Senegal, three types of G6PD variants were discovered: (1) fast variants, common Negro G6PD A +; the frequency of the Gd A + gene was 0.183; (2) deficient G6PD A--, occurring with a fairly low frequency: 0.079, and (3) some individuals were carriers of a slow moving electrophoretic variant with normal activity. After purification, the analysis of kinetic parameters showed that this enzyme was closely similar to G6PD Tacoma. We proposed to label it 'G6PD Tacoma-like'. The incidence of this mutation in the whole group studied was 0.020. G6PD Tacoma-like may be common in some African tribes.     

Human malic enzyme: High-frequency polymorphism of the mitochondrial form

Polymorphic variation of the human mitochondrial malic enzyme was detected in Caucasians and Negroes. The frequencies of the two alleles determining the three mitochondrial malic enzyme phenotypes were 0.69 and 0.31 in the Caucasian sample and 0.82 and 0.18 in the much smaller Negro sample. The distribution of phenotype frequencies among the 85 Caucasian males shows a significant deviation from Hardy-Weinberg equilibrium proportions. Two interconvertible forms of the cytoplasmic malic enzyme are described in human brain tissue, together with one variant in 132 Caucasian individuals.This study was supported by grant GM 15253 from the National Institutes of Health and by Institutional Cancer Grant IN-26 from the American Cancer Society. One of us (G.S.O.) is a National Genetics Foundation Fellow; formerly Special Fellow, U.S. Public Health Service (5F3-HD 43,122-02).     

Digital dermatoglyphics in two Afro-American communities of Central America

The present report provides analytical data of digital dermatoglyphics on 150 subjects (79 males, 71 females) from Bluefields, Nicaragua and 146 (98 males, 48 females) from Livingston, Guatemala. They were classified as belonging to three sub-samples: Negroes (Bluefields) or Black-Caribs (Livingston), Ladinos and Creoles. However due to the very small size of some sub-samples, the findings, related to brief demographical and ethno-historical perspectives, were compared, for Pattern Intensity Index and Total Finger Ridge Count, with those of other human groups. Statistically significant differences occur between Negroes (Bluefields) and Black-Caribs (Livingston) but no sharp differences were found within the other sub-samples. Because the literature doesn't contain dermatoglyphic data for the Afro-American Communities spread over the Atlantic coast of Middle America, from Belize to Panama, and really few data have been collected regarding other anthropological observations, large gaps remain to be filled about these interesting inbreeding populations. It is right to remark that an investigation oriented to a population mixture study necessitates the collection of more dermatoglyphic data before the dermatoglyphic results can be properly evaluated.     

Mylohyoid and jugular foramen bridging in pre-Columbian Chileans

The occurrence of mylohyoid groove bridging and jugular foramen bridging was determined in a population of adult Pre-Columbian Chileans. Two hundred forty-one crania (110 males, 131 females) were examined for jugular foramen bridging and 464 mandibles (252 males and 212 females) were observed for mylohyoid groove bridging. The overall incidence of jugular foramen bridging was 14.94%, with females showing a higher occurrence (18.32%) than males (10.91%); however, no statistical significance was found between the sexes. The right side showed a greater incidence than the left, but again no statistical difference was noted and the occurrence of this trait was found to be associated between the sides. This frequency of jugular foramen bridging is higher than that found in other studies and approaches that reported in North American Eskimo populations. In the case of mylohyoid groove bridging, the incidence was 4.09% with no difference found between the sexes. This frequency of occurrence is less than the values reported previously for the other American populations of Mongoloid ancestry including the Pre-Columbian Peruvian population. The importance of nonmetric skeletal traits for defining population groups and their usefulness as anthropological tools is discussed. It is concluded that hard tissue variations such as bony bridging may be reliable markers to aid in discretely identifying population groups, but their importance can be significantly enhanced by coupling as many traits as possible in future studies.     

Unusually low sexual dimorphism of endocranial capacity in a Zulu cranial series

The mean cranial capacities of 50 male and 50 female Zulu crania were found to be 1373.3 +/- 107.4 ml for males and 1251.2 +/- 101.1 ml for females (means +/- SD). The male value resembles that of other Negro groups, while the female value is somewhat higher than the value for Negro crania as a whole. The index of sexual dimorphism is 8.9%, which is low when compared with those of other Negroid series and other populations. The possible causes for this form of a low sexual dimorphism are as follows: A negative secular trend, with the assumption that the Zulu crania were larger than those of the reference populations of African Negroids before the start of the secular trend change. This would seem to be the most likely possibility, with some supporting evidence for both parts of the explanation. An absence of secular trend, with a demographic sampling aberration, in which large females and small males of the population are sampled. This possibility cannot be totally excluded. An absence of secular trend, with a genetic difference in sexual dimorphism for cranial capacity between the Zulu and the reference populations. While this possibility cannot be excluded, it would be the least preferable explanation.     

Fluoride in drinking water and osteosarcoma incidence rates in the continental United States among children and adolescents

IntroductionIt has been suggested that fluoride in drinking water may increase the risk of osteosarcoma in children and adolescents, although the evidence is inconclusive. We investigated the association between community water fluoridation (CWF) and osteosarcoma in childhood and adolescence in the continental U.S.MethodsWe used the cumulative osteosarcoma incidence rate data from the CDC Wonder database for 1999–2006, categorized by age group, sex and states. States were categorized as low (≤30%) or high (≥85%) according to the percentage of the population receiving CWF between 1992 and 2006. Confidence intervals for the incidence rates were calculated using the Gamma distribution and the incidence rates were compared between groups using Poisson regression models.ResultsWe found no sex-specific statistical differences in the national incidence rates in the younger groups (5–9, 10–14), although 15–19 males were at higher risk to osteosarcoma than females in the same age group (p < 0.001). Sex and age group specific incidence rates were similar in both CWF state categories. The higher incidence rates among 15–19 year old males vs females was not associated with the state fluoridation status. We also compared sex and age specific osteosarcoma incidence rates cumulated from 1973 to 2007 from the SEER 9 Cancer Registries for single age groups from 5 to 19. There were no statistical differences between sexes for 5–14 year old children although incidence rates for single age groups for 15–19 year old males were significantly higher than for females.ConclusionOur ecological analysis suggests that the water fluoridation status in the continental U.S. has no influence on osteosarcoma incidence rates during childhood and adolescence.     

The dermatoglyphics of American Negroes

Digital and palmar dermatoglyphics of 184 male and 224 female normal American Negroes were evaluated for digital patterns, digital ridge counts, palmar patterns, palmar main line terminations, accessory triradii and palmar creases. All subjects were seven year olds examined and found free of chronic or other genetic diseases. The results were presented for the left and right hand for the most part comparable to those of the African and other American Negro groups reported earlier. The distributions of the various dermatoglyphic features among the Negroes taken as a group were compared to those of the other racial groups and their differences were discussed.     

Incidence of numerical chromosome aberrations in meningioma tumors as revealed by fluorescence in situ hybridization using 10 chromosome-specific probes

OBJECTIVE: Although information on the cytogenetic characteristics of meningioma tumors has accumulated progressively over the past few decades, information on the genetic heterogeneity of meningiomas is still scanty. The aim of the present study was to analyze by interphase fluorescence in situ hybridization (FISH) the incidence of numerical abnormalities for chromosomes 1, 9, 10, 11, 14, 15, 17, 22, X, and Y in a group of 70 consecutive meningioma tumors. Another goal was to establish the potential associations among the altered chromosomes, as a way to assess both intertumoral and intratumoral heterogeneity. METHODS: For the purpose of the study, 70 patients diagnosed with meningioma were analyzed. Interphase FISH for the detection of numerical abnormalities for chromosomes 1, 9, 10, 11, 14, 15, 17, 22, X, and Y was applied to fresh tumor samples from each of the patients studied. RESULTS: The overall incidence of numerical abnormalities was 76%. Chromosome Y in males and chromosome 22 in the whole series were the most common abnormalities (46% and 61%, respectively). Despite the finding that monosomy of chromosome 22/22q(-) deletions are the most frequent individual abnormality (53%), we have observed that chromosome gains are significantly more common than chromosome losses (60% versus 40%). Chromosome gains corresponded to abnormalities of chromosomes 1 (27%), 9 (25%), 10 (23%), 11 (22%), 14 (33%), 15 (22%), 17 (23%), and X in females (35%) and males (23%) whereas chromosome losses apart from chromosome 22 frequently involved chromosomes 14 (19%), X in males (23%), and Y in males (32%). Although an association was found among most gained chromosomes on one side and chromosome losses on the other side, different association patterns were observed. Furthermore, in the latter group, monosomy 22/22q(-) was associated with monosomy X in females and monosomy 14/14q(-) was associated with nulisomy Y in males. In addition, chromosome losses usually involved a large proportion of the tumor cells whereas chromosome gains were restricted to small tumor cell clones, including tetraploid cells. CONCLUSIONS: Our results show that meningiomas are genetically heterogeneous tumors that display different patterns of numerical chromosome changes, as assessed by interphase FISH.