Study of genetic diversity of KIR and TLR in the Rabhas, an endogamous primitive tribe of India

Genomics of rare genetic diseases-experiences from India

Home to a culturally heterogeneous population, India is also a melting pot of genetic diversity. The population architecture characterized by multiple endogamous groups with specific marriage patterns, including the widely prevalent practice of consanguinity, not only makes the Indian population distinct from rest of the world but also provides a unique advantage and niche to understand genetic diseases. Centuries of genetic isolation of population groups have amplified the founder effects, contributing to high prevalence of recessive alleles, which translates into genetic diseases, including rare genetic diseases in India.Rare genetic diseases are becoming a public health concern in India because a large population size of close to a billion people would essentially translate to a huge disease burden for even the rarest of the rare diseases. Genomics-based approaches have been demonstrated to accelerate the diagnosis of rare genetic diseases and reduce the socio-economic burden. The Genomics for Understanding Rare Diseases: India Alliance Network (GUaRDIAN) stands for providing genomic solutions for rare diseases in India. The consortium aims to establish a unique collaborative framework in health care planning, implementation, and delivery in the specific area of rare genetic diseases. It is a nation-wide collaborative research initiative catering to rare diseases across multiple cohorts, with over 240 clinician/scientist collaborators across 70 major medical/research centers. Within the GUaRDIAN framework, clinicians refer rare disease patients, generate whole genome or exome datasets followed by computational analysis of the data for identifying the causal pathogenic variations. The outcomes of GUaRDIAN are being translated as community services through a suitable platform providing low-cost diagnostic assays in India. In addition to GUaRDIAN, several genomic investigations for diseased and healthy population are being undertaken in the country to solve the rare disease dilemma.In summary, rare diseases contribute to a significant disease burden in India. Genomics-based solutions can enable accelerated diagnosis and management of rare diseases. We discuss how a collaborative research initiative such as GUaRDIAN can provide a nation-wide framework to cater to the rare disease community of India.

Environmental selection influences the diversity of TLR genes in ethnic Rajbanshi population of North Bengal Region of India

Background

Toll-like receptors are the mediators of the innate immune response to pathogens. In human, this gene family regulates the inflammatory pathways and is associated with the susceptibility to infection.

Subjects and methods

The distribution and the diversity patterns of TLR genes in Rajbanshi population (n = 85) who are the inhabitants of the Northern part of West Bengal, have been investigated in the present study. PCR-SSP was done for all the ten TLR genes. We have also constructed the phylogenetic tree principal component analysis and genetic distance for all the four populations.

Results

It has been observed that in Rajbanshi population, the frequency of TLR8 (0.894) is higher and the frequency of TLR2 (0.176) is very low. Dendrogram based analysis, as well as the PCA plot, documented the closeness of Rajbanshi and Gurkha population. However, Rabha is distantly related to Rajbanshi population though evidences suggest their emergence from the same East-Asian lineage. Genetic distances between Rajbanshi–Gurkha and Rajbanshi–Muslim are very much smaller than that of Rajbanshi–Rabha populations.

Interpretations & conclusions

Therefore, it may be concluded that Rajbanshi, Gurkha and Muslims are very much mixed populations and have genetic closeness due to exposure to similar environmental conditions. On the other hand, the Rabhas strictly follow the endogamy and are restricted to a particular region and therefore maintain considerable distances with the other three populations. The data showed some interesting observations which deviate the contemporary thought in respect to the population genetics.