Virendra P. Chopra

Bio: Virendra P. Chopra is an academic researcher from University of Hamburg. The author has contributed to research in topics: Population & Genetic distance. The author has an hindex of 6, co-authored 7 publications receiving 103 citations. Previous affiliations of Virendra P. Chopra include Indian Statistical Institute.

Opportunity for natural selection among the Indian populations.

Abstract: A critical review of data on opportunity for natural selection among the Indian populations has been made. These data on 96 populations were analysed according to regional, habitat, and socioeconomic backgrounds. The trends observed on the basis of these Indian data have been compared with worldwide data and data from industrialized nations. As in the industrialized nations, a gradual decrease in I(m) and I(t) is observed with improving socioeconomic and technological status in the Indian populations. The Indian situation is similar to that of the first phase in the modern demographic transition among the industrialized nations.

Quantitative dermatoglyphics and population structure in Northwest India.

Abstract: The nature and extent of dermatoglyphic variation in northwest India is examined with the help of 28 quantitative variables-20 finger ridge counts and 8 palmar pattern ridge counts-among 12 endogamous populations. These populations represent the entire spectrum of ethnic and socioeconomic variation of the region and are presently distributed in three different states-Rajasthan, Punjab, and Himachal Pradesh. Of a total sample of 1,160 adult males, about 100 from each group were considered. Multiple discriminant analysis and R-matrix analysis were used to derive population relationships and patterns of external gene flow, respectively. Published data on genetic markers were reanalyzed to make the comparative evaluation of the patterns with reference to dermatoglyphs. Both the discriminant analysis and the F(ST) from R-matrix analysis suggest highly significant discrimination among the northwestern groups, whether one uses only 20 finger ridge count variables or all 28 variables, including the 8 palmar pattern ridge counts. The 8 palmar variables add very little to the variation explained by the 20 finger ridge count variables. F(ST) values suggest that the populations of Punjab are most homogeneous and those of Himachal Pradesh most heterogeneous. However, the levels of differentiation are similar for dermatoglyphs and genetic markers. The pattern of external gene flow as inferred through R-matrix analysis is consistent with the breeding and population structure of the groups, although genetic markers portray a relatively more realistic picture. Overall, the patterns of variation observed in dermatoglyphs and genetic markers are consistent with different dimensions of population structure; whereas dermatoglyphs conform more to the geographic pattern and less to ethnic resemblance, the reverse is true in the case of genetic markers. Am. J. Hum. Biol. 12:315-326, 2000. Copyright 2000 Wiley-Liss, Inc.

Opportunity for natural selection with special reference to population structural measures among the Vadde.

Abstract: Crow's indices of opportunity for natural selection have been studied among the Vadde, a fishing community of Kolleru Lake, Andhra Pradesh, India. The sample comes from 15 of the 60 fishing villages. The indices were computed both at the level of village and population units. A village sample of Palle, another fishing group in the area, has also been analysed for the purpose of comparison. An attempt has been made to explain variation in selection indices among the villages using population structural measures. A wide variation is found in both the fertility and mortality indices between the villages. The values were compatible with those found for other fishing groups studied previously, and in the middle of the range observed for the Indian populations (about 100) studied so far. Population structural measures are found to explain a significant amount of variation in Im and It but not in the fertility index.

Genetic differentiation among four groups of fishermen of the eastern coast, India.

Abstract: The four endogamous groups of fishermen living around the city of Puri, located on the eastern coast of India, were studied for blood groups, red cell enzymes and serum proteins (11 loci). Only 1.3% of the total diversity among the groups studied is due to differences between them (G ST = 0.013). The genetic distances between populations were estimated using Edwards and Cavalli-Sforza's method. The pattern of genetic distance reflects the geographical distribution of these groups. In general, these observations support the patterns of variation based on anthropometric and dermatoglyphic variables.

Biological affinities between the migrant groups of fishermen of Puri Coast, Orissa, India.

Abstract: Biological affinities between the three endogamous groups of marine fishermen of Puri are examined with the help of nine anthropometric measurements and 22 dermatoglyphic traits of fingers and palms. The results are interpreted in the light of their ethnic, geographical, and migrational backgrounds. Multiple discriminant analysis and Mahalanobis's generalized distances suggest higher discrimination of populations with reference to anthropometric traits as compared to that in dermatoglyphic variables. While the nature of interpopulation distances conforms to the geographic pattern in anthropometrics, no clear picture emerges in the dermatoglyphic distances supporting either ethnic or geographic evidence.

People of India: Biological diversity and affinities

Abstract: The Indian subcontinent comprises a vast collection of peoples with different morphological, genetic, cultural, and linguistic characteristics. While much of this variability is indigenous, a considerable fraction of it has been introduced through large-scale immigrations into India in historical times. From an evolutionary standpoint, it is of immense interest to quantify biological diversity in contemporary human populations, to study biological affinities and to relate observed patterns of affinities with cultural, linguistic and demographic histories of populations. Such efforts are intended to shed light on the peopling of India. The purpose of this paper is to present a broad overview of the physical (anthropometric) and genetic diversities and affinities of the peoples of India. I shall also attempt to examine how well biological, particularly genetic, diversities and affinities correlate with geographical, socio-cultural, and linguistic diversities and affinities. © 1998 Wiley-Liss, Inc.

Estimation of adult stature from fragmentary tibias.

Abstract: LInear-regression equations derived from measurements of tibial condyles from 100 individuals in the Hamann-Todd Collection retrodicted known stature with a level of confidence comparable to many of the existing stature-estimation techniques. Statures of an independent control group were estimated with similar success. The strong linear relationship that exists between the length of the tibia and the size of the condyles allows adult stature (of American whites and blacks) to be estimated from the proximal tibia. Since complete tibial length is not required, this technique could prove useful in forensic science and archaeological cases where less-than-intact elements are recovered.

Structure of Human Populations in India

Abstract: The interpretation of the temporal and spatial variation of gene frequencies in populations is one of the main aims of population genetics. In addition to systematic evolutionary processes (mutation, selection and admixture), non-systematic factors such as size, density, and the distribution of a population, the nature of mate selection within a population, and differential fertility and viability also influence the genetic composition of a population. These non-systematic factors are the most important components of the structure of human populations. It is now well known that very different patterns of these non-systematic factors exist in human populations.

A demographic transition altered the strength of selection for fitness and age-specific survival and fertility in a 19th century American population.

Abstract: Modernization has increased longevity and decreased fertility in many human populations, but it is not well understood how or to what extent these demographic transitions have altered patterns of natural selection. I integrate individual-based multivariate phenotypic selection approaches with evolutionary demographic methods to demonstrate how a demographic transition in 19th century female populations of Utah altered relationships between fitness and age-specific survival and fertility. Coincident with this demographic transition, natural selection for fitness, as measured by the opportunity for selection, increased by 13% to 20% over 65 years. Proportional contributions of age-specific survival to total selection (the complement to age-specific fertility) diminished from approximately one third to one seventh following a marked increase in infant survival. Despite dramatic reductions in age-specific fertility variance at all ages, the absolute magnitude of selection for fitness explained by age-specific fertility increased by approximately 45%. I show that increases in the adaptive potential of fertility traits followed directly from decreased population growth rates. These results suggest that this demographic transition has increased the adaptive potential of the Utah population, intensified selection for reproductive traits, and de-emphasized selection for survival-related traits.