Molecular genetic perspectives on the origin of the Lyngngam tribe of Meghalaya, India

Meghalaya, one of the Northeast Indian states, is inhabited by two major tribal clusters, Khasi and Garo. The disputed origin of the Lyngngam tribe of Meghalaya is a result of their geographic distribution, which is sandwiched between that of the above two major tribal clusters. Our earlier analysis of ethnohistoric, linguistic and demographic data suggested the neighbouring Khasi and Garo as the putative parental population(s) of Lyngngam. In this paper, we have investigated the Lyngngam, Garo and all the 7 subtribes of Khasi of Meghalaya using molecular genetic markers-autosomal, Y-chromosome and mtDNA-to explore the possible origin of the Lyngngam tribe. We obtained admixture estimates for Lyngngam versus the putative parental populations. While autosomal STRs and mtDNA results clearly suggest Khasi origin of the Lyngngam, Y-STR distances show greater proximity of Lyngngam to the Garo. Further, the comparative analysis of the Y-Chromosome and mtDNA haplogroup data on relevant Austro-Asiatic and Tibeto-Burman populations from South and Southeast Asia, published by us earlier, clearly exclude the possibility of Lyngngam origin from outside Meghalaya. The molecular genetic evidence in conjunction with the linguistic, demographic and ethno-historic information clearly suggests Khasi origin of the Lyngngam tribe

Role of Progesterone Receptor Polymorphisms in the Recurrent Spontaneous Abortions: Indian Case

Background: We attempt to ascertain if the 3 linked single nucleotide polymorphisms (SNPs) of the Progesterone Recepto

Role of Androgen Receptor CAG Repeat Polymorphism and X-Inactivation in the Manifestation of Recurrent Spontaneous Abortions in Indian Women

The aim of the present study was to investigate the role of CAG repeat polymorphism and X-chromosome Inactivation (XCI) pattern in Recurrent Spontaneous Abortions among Indian women which has not been hitherto explored. 117 RSA cases and 224 Controls were included in the study. Cases were recruited from two different hospitals - Lakshmi Fertility Clinic, Nellore and Fernandez Maternity Hospital, Hyderabad. Controls were roughly matched for age, ethnicity and socioeconomic status. The CAG repeats of the Androgen Receptor gene were genotyped using a PCR-based assay and were analysed using the GeneMapper software to determine the CAG repeat length. XCI analysis was also carried out to assess the inactivation percentages. RSA cases had a significantly greater frequency of allele sizes in the polymorphic range above 19 repeats (p = 0.006), which is the median value of the controls, and in the biallelic mean range above 21 repeats (p = 0.002). We found no evidence of abnormal incidence of skewed X-inactivation. We conclude that longer CAG repeat lengths are associated with increased odds for RSA with statistical power estimated to be ∼90%

Austro-Asiatic Tribes of Northeast India Provide Hitherto Missing Genetic Link between South and Southeast Asia

Northeast India, the only region which currently forms a land bridge between the Indian subcontinent and Southeast Asia, has been proposed as an important corridor for the initial peopling of East Asia. Given that the Austro-Asiatic linguistic family is considered to be the oldest and spoken by certain tribes in India, Northeast India and entire Southeast Asia, we expect that populations of this family from Northeast India should provide the signatures of genetic link between Indian and Southeast Asian populations. In order to test this hypothesis, we analyzed mtDNA and Y-Chromosome SNP and STR data of the eight groups of the Austro-Asiatic Khasi from Northeast India and the neighboring Garo and compared with that of other relevant Asian populations. The results suggest that the Austro-Asiatic Khasi tribes of Northeast India represent a genetic continuity between the populations of South and Southeast Asia, thereby advocating that northeast India could have been a major corridor for the movement of populations from India to East/Southeast Asia

Mitochondrial DNA variations associated with recurrent pregnancy loss among Indian women

Several genetic factors have been found to be associated with recurrent pregnancy loss (RPL). However, not many attempts have been made to associate the mitochondrial DNA (mtDNA) variations with RPL. Therefore, we have analyzed the complete mtDNA of 100 women with RPL and 12 aborted fetal tissues. Our analysis revealed a total of 681 variations, most of which were in NADH Dehydrogenase (ND) genes that encode mitochondrial enzyme Complex I. Presence of T4216C variation (ND1 gene) in 9% of the RPL women and several pathogenic, and novel mutations suggest the role of mtDNA variations in RPL

Genotype distribution of PROGINS insertion; (T1) wild type (no insertion) and (T2) insertion allele.

<p>Genotype distribution of PROGINS insertion; (T1) wild type (no insertion) and (T2) insertion allele.</p

Genotype distribution of the PR mutations; (*1) wild type (G1031, G1978, and C2310) and (*2) mutant allele.

<p>Genotype distribution of the PR mutations; (*1) wild type (G1031, G1978, and C2310) and (*2) mutant allele.</p

Gel picture showing bands for homozygotes (T1) allele, heterozygotes (T1/T2), and homozygote (T2) allele run on 2% agarose.

<p>Lane 3, 4, 5, and 6 are heterozygotes, and lane 13 is homozygous for the T2 allele and the remaining are homozygous for the T1 allele.</p