Diversified genomic contribution among south Indian populations--a study on four endogamous groups of Andhra Pradesh.

BACKGROUND: The present study examines genomic variation among three tribal (Nayakpod, Thoti and Kolam) and a caste (Niyogi Brahmin) population groups of Andhra Pradesh, south India. AIM: The present study examined the genomic diversity of the populations in relation to other population groups of India using 20 autosomal loci. SUBJECTS AND METHODS: A total of 204 blood samples from the population groups described above were collected and analysis was carried out following standard protocols. RESULTS: All markers were found to be polymorphic in these groups except AluCD4 among Thotis. High average heterozygosity values (0.3927 among Thotis to 0.4268 among Brahmins) are comparable with the available autosomal (Alu and restriction site polymorphisms) data for the Nilgiri hill tribes of Tamil Nadu, south India. The gene differentiation value (Gst) was found to be 4.2. The principal coordinate analysis (PCO) based on data from the 20 markers presents a smaller cluster of presently studied populations than that of the Nilgiri hill tribes of Tamil Nadu, south India. CONCLUSION: Although the presently studied populations of Andhra Pradesh have heterozygosity similar to that of Nilgiri hill populations, the former are more closely placed on the PCO plot than the latter, who are more scattered. Also the gene differentiation (Gst) of the former is much lower than that of the latter, indicating considerable regional variation in the inflow of genes from diverse ethnic groups within south India.

Folic acid, dietary habits, and homocysteine levels in relation to neural tube defects: A case-control study in North India.

PURPOSE: The present study attempts to understand the complex contribution of biochemical (plasma homocysteine) and nutritional parameters (dietary pattern and folate supplementation) to the neural tube defects (NTDs) affected pregnancies and controls in North Indian population. METHODS: Case-control study design was adopted to assess the role of folic acid, dietary habits, and homocysteine in relation to NTD births. The subjects comprised of 130 mothers of affected children (cases) and 233 mothers of healthy children (controls), who were either carrying NTD fetus or gave birth to NTD child. RESULTS: The mean homocysteine levels were elevated in cases (15.71 ± 8.35 µmol/L) as compared to controls (12.87 ± 5.95 µmol/L) but were lower among the non-vergetarians (13.55 ± 6.64 µmol/L) than the vegetarians (14.78 ± 7.93 µmol/L). Vegetarian dietary habit increased the NTD risk by 1.6 fold (95% CI = 1.0-2.7) while folic acid supplementation demonstrated a protective effect for conceptions (OR = 0.59; 95% CI = 0.3-0.9). Consumption of folic acid with non-vegetarian diet witnessed lowering of homocysteine in cases (12.88 ± 6.81 µmol/L) and in controls (11.85 ± 5.54 µmol/L), with an odds ratio depicting a 3.1 fold risk for consuming vegetarian diet without folic acid supplementation during the peri-conceptional period. CONCLUSION: It is suggested that plasma hyperhomocysteinemia bears negative impact on child-bearing women group, of north Indian ancestry, in modulating the risk of NTDs. Efforts should be made to enhance awareness regarding folic acid and vitamin B12 (non-vegetarian diet) supplementations alongwith proper nutritional intake among women, especially those consuming vegetarian diet to control homocysteine levels in order to reduce the risk of NTDs.