Genomic diversity and affinities in population groups of North West India: An analysis of Alu insertion and a single nucleotide polymorphism

The North West region of India is extremely important to understand the peopling of India, as it acted as a corridor to the foreign invaders from Eurasia and Central Asia. A series of these invasions along with multiple migrations led to intermixture of variable populations, strongly contributing to genetic variations. The present investigation was designed to explore the genetic diversities and affinities among the five major ethnic groups from North West India; Brahmin, Jat Sikh, Bania, Rajput and Gujjar. A total of 327 individuals of the abovementioned ethnic groups were analyzed for 4 Alu insertion marker loci (ACE, PV92, APO and D1) and a Single Nucleotide Polymorphism (SNP) rs2234693 in the intronic region of the ESR1 gene. Statistical analysis was performed to interpret the genetic structure and diversity of the population groups. Genotypes for ACE, APO, ESR1 and PV92 loci were found to be in Hardy–Weinberg equilibrium in all the ethnic groups, while significant departures were observed at the D1 locus in every investigated population after Bonferroni's correction. The average heterozygosity for all the loci in these ethnic groups was fairly substantial ranging from 0.3927 ± 0.1877 to 0.4333 ± 0.1416. Inbreeding coefficient indicated an overall 10% decrease in heterozygosity in these North West Indian populations. The gene differentiation among the populations was observed to be of the order of 0.013. Genetic distance estimates revealed that Gujjars were close to Banias and Jat Sikhs were close to Rajputs. Overall the study favored the recent division of the populations of North West India into largely endogamous groups. It was observed that the populations of North West India represent a more or less homogenous genetic entity, owing to their common ancestral history as well as geographical proximity.     

Inbreeding effects on metrical phenotypes among North Indian Children

This study aimed to examine the effects of inbreeding on 12 quantitative phenotypes like body weight, height, sitting height, head circumference, head length, head breadth, chest circumference, verbal, performance and full scale intelligence quotients, systolic and diastolic blood pressures among North Indian Children. The sample consisted of 3,253 subjects (1,683 males and 1,570 females) including offspring of first cousins, first cousins once removed, second cousins, (inbred part of samples) and unrelated spouses (non-inbred part of samples) ranging in age from 6 to 14 years from the Aligarh district, Uttar Pradesh in North India. Samples were selected purposively to estimate the average inbreeding coefficients based on 3 ancestral generations and using Wright's path method. The average inbreeding coefficient of the present inbred part of sample is 0.04609. The mean ages of males and females were almost equal for both inbred and non-inbred individuals. A significant reduction of means (p < 0.05) or inbreeding depression has been observed in inbred series for all anthropometric and psychometric traits for both the sexes. A significant elevation of mean with inbreeding is observed for systolic and diastolic blood pressure. The average inbreeding depression per 10% inbreeding appeared very high in verbal IQ (> or =23), performance IQ (> or =40), full scale IQ (> or =28), systolic blood pressure (> or =10) and diastolic blood pressure (> or =12) among both sexes. On the whole, relatively greater amount of inbreeding effects are apparent among all measures of intelligence quotient and blood pressures compared to the anthropometric traits. The results of the present work have thrown light on the nature and mechanism of genetic effects of inbreeding on certain quantitative traits in human.     

Age-specific differences in blood pressure among inbred and non-inbred north Indian children

Genetic and inbreeding influences on systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure (MBP) were examined among 3015 children (1527 males and 1488 females) from the Aligarh district, Uttar Pradesh in north India. The subjects included offspring of first cousins, first cousins once removed, second cousins and unrelated spouses from the same population. The measurements of the inbred children were compared with those of their non-inbred relatives in at least 80% of the cases (matched controls). Two unique findings emerge from this study. First a consistent increase in mean values of SBP, DBP and MBP with increasing inbreeding coefficients have been observed among all age groups, including both the sexes. The results suggest that the hypothesis for a recessive gene or genes could be held responsible for higher BP. Secondly, the effects of inbreeding on mean blood pressure among children and adults may not necessarily be in the same direction. It can be said, therefore, that studies on inbreeding effects using matched controls may provide more direct information regarding the genetics of blood pressure, which has been considerably underestimated in earlier studies.