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R L Jantz

Publications and source records attributed to R L Jantz.

At least 55 records · Page 3Linked to original sources
PubMed1978

Finger and palmar dermatoglyphics of a Yoruba (Nigeria) sample.

Finger and palm prints of 126 male and 55 female Yoruba are reported using both quantitative and qualitative procedures. In general, the Yoruba fit into established geographical gradients for sub-saharan African populations. Whorl frequencies on the digits are relatively low, as is the frequency of palmar patterning. Finger ridge-counts, those of males in particular are high by African standards, and much higher than the previously reported data from Nigeria. Due to the lack of data on patterns of geographic variation in total finger ridge-count, little can be made of these findings at present.

Dermatoglyphics↗
PubMed1977

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.

Black People↗
PubMed1977

Factor analysis of finger ridge-counts in Blacks and Whites.

Finger ridge-counts of an American White, American Black and an African Black sample were subjected to factor analysis. The analysis was carried out using correlation matrices computed from 10-ridge counts, each finger being represented by its largest count, and from 20 ridge-counts, using both radial and ulnar counts for each finger. The 20 count analysis was much more informative, demonstrating the relative independence of the radial and ulnar sides of the fingers. Moreover, the radial and ulnar counts themselves generally resulted in two factors reflecting counts on the ulnar digits and the median digits. The independence of the thumb was also demonstrated. There was considerable intersample consistency, although some evidence of sex and race variation was observed.

Black People↗
PubMed1977

Inbreeding, marital movement, and genetic isolation of a rural Appalachian population.

Genealogical, marital, birthplace and age-at-marriage data were collected on a random sample of 275 reproducing couples from the population of a rural Appalachian county in north-eastern Tennessee. Genealogies covering the three extant generations provided the data for a surname isonymy analysis to determine the amount of inbreeding prevalent, while the marital, birthplace and age at marriage data were used to ascertain the components of marital movement, i.e., marital distance, orientation of marital movement, spatial exogamy, and "diffusion". The effective breeding population and effective immigration rate were calculated for the county population and these in turn were used to compute the coefficient of breeding isolation for the currently reproduction population. Our conclusions agree with those of an earlier genetic and demographic study on one segment of the same population. The more extensive demographic analysis illustrates the value of such studies as this for providing background for interpretations of genetic variation.

Consanguinity↗
PubMed1976

The relation between total finger ridge-count and variability of counts from finger: genetic implications of racial variation.

The measure of ridge-count diversity, S/square root 10, was computed for a sample of American Whites, American Blacks and African Blacks, and the regression of S/square root 10 on total ridge-count was determined for each group. The shapes of the regression lines differed considerably. The American White curve was very similar to that obtained by Holt in an English sample, while the two Negro curves generally showed lower lower S/square root 10 values for ridge-counts over 80. The American Negro curve was found to behave like a mixture of the White and African Negro curve to a degree approximating to the fraction of White genes in their gene pool. Holt's parent-child data are used to construct a simple test of the hypothesis that that S/square root 10 reflects zygosity in total ridge-count genotypes. The preliminary results support this hypothesis.

Black or African American↗
PubMed1975

Population variation in asymmetry and diversity from finger to finger for digital ridge-count.

Population variation in ridge-count asymmetry and diversity from finger to finger has received scant attention in dermatoglyphic studies. Asymmetry, in particular, has generally been attributed to environmental effects operating during the formation of dermal ridges. Examination of samples from several groups of diverse racial background revealed the existence of considerable population variation with respect to finger ridge-count asymmetry and diversity from finger to finger. Patterning along population lines suggests a genetic rather than environmental basis for such variation. The genetic mechanisms responsible for ridge-counts may also mediate asymmetry and diversity, or the degree of developmental stabiltiy in different populations may itself be under genetic control.

Africa↗
PubMedDate not supplied

Finger ridge-count variability in sub-Saharan Africa.

Mean finger ridge-count data were obtained, primarily from literature sources, for 31 male and 24 female sub-Saharan African samples. The 10 finger ridge-counts and total ridge-count were used as independent variables in a multiple regression analysis, latitude and longitude serving in turn as the dependent variables. The results show that it is not the magnitude of the ridge-counts themselves that is important, but rather contrasts between groups of digits. The most important geographically patterned variation in ridge-counts consists of contrasts between digits 4 and 5 and digits 2 and 3. South and south-east African populations are characterized by low contrasts, west Africans by high contrasts and, south-west Africans are intermediate. The geographical patterning of the contrast agrees well with known patterns of gene flow into and within the continent as determined by serological genes. Principal components analysis was also carried out to determine whether within-group components corresponding to the geographically relevant between-group variation could be identified. The third, fourth and fifth components drew the same types of contrasts between the groups of digits identified in the multiple regression analysis, but they were relatively unimportant. The geographically important principal components would have been overlooked in a traditional multivariate analysis of finge ridge-counts, since the analysis would have been dominated by pattern size. We conclude that finger ridge-counts are potentially very useful in population studies, but account must be taken of their multicomponent nature.

Africa, Southern↗
PubMedDate not supplied

Dermatoglyphic asymmetry as a measure of canalization.

Fluctuating asymmetry has been used frequently, especially in the experimental literature, as a measure of developmental stability. However, the relationship between asymmetry and the ability of the genotype to produce an adaptive phenotype is far from clear. In this paper we evaluate the relationship between asymmetry and the mean of a quantitative trait in humans. The trait used is the a-b ridge-count, the count between the a and b triradius in the second interdigital area of the palm. The extremes of both ends of the a-b count distribution exhibit greater asymmetry than values closer to the mean. This evidence suggests that dermatoglyphic asymmetry does reflect to some extent the degree to which the developing phenotype is controlled.

Analysis of Variance↗