Genetic Diversity Across the Indian Subcontinent

Context:

Recently, a study by Institute for Human Genetics, University of California, has found stark genetic differences between people from different regions of the Indian subcontinent.

Relevance:

GS III: Science and Technology

Dimensions of the Article:

1. Methodology of the Genetic Diversity Study
2. Key Findings of the Genetic Diversity Study

Methodology of the Genetic Diversity Study

The study conducted by the Institute for Human Genetics at the University of California utilized a robust methodology involving DNA analysis and whole-genome sequencing to investigate genetic diversity across the Indian subcontinent.

Here are the key aspects of the methodology:

Sample Collection:

• Diverse Cohort: The researchers collected DNA samples from a diverse cohort of approximately 5,000 individuals. This cohort represented populations from India, Pakistan, Bangladesh, as well as select communities from Malay, Tibetan, and other South-Asian regions.

DNA Analysis:

• Whole-Genome Sequencing: The primary technique employed in the study was Whole-Genome Sequencing (WGS). This advanced genetic analysis method involves sequencing the entire DNA content of an individual’s genome.
• Genetic Variations: The researchers meticulously examined each individual’s DNA for variations, which encompassed changes, deletions, insertions, and substitutions of DNA base pairs, often referred to as ‘letters.’
• Data Collection and Comparison: The genetic data obtained from the samples were meticulously collected and compared, allowing the researchers to identify and analyze the genetic differences and variations among the studied populations.

Data Interpretation:

• Comparative Analysis: The collected genetic data were subjected to rigorous comparative analysis. This involved comparing the sequences of DNA base pairs among different individuals and populations.
• Identification of Differences: The analysis focused on identifying instances where DNA exhibited changes, deletions, or additions of base pairs. These genetic variations are indicative of the unique genetic makeup of different populations.

Findings and Conclusions:

• Genetic Signatures: By analyzing the genetic variations, the researchers were able to discern distinctive genetic signatures associated with various regions and communities within the Indian subcontinent.
• Interpretation: The observed genetic differences were interpreted in the context of historical migrations, cultural interactions, and geographical factors that have shaped the genetic diversity of the populations studied.

Significance and Implications:

• Insights into Genetic Diversity: The methodology employed in this study provided valuable insights into the genetic diversity, admixture, and historical evolution of populations across the Indian subcontinent.
• Scientific Understanding: The comprehensive analysis of DNA variations contributes to the scientific understanding of human genetic diversity, migration patterns, and historical interactions within the region.

Key Findings of the Genetic Diversity Study

The study conducted by the Institute for Human Genetics at the University of California yielded several significant findings that shed light on the genetic diversity and population dynamics within the Indian subcontinent.

Limited Mixing and Endogamous Practices:

• Limited Intercommunity Mixing: The study revealed limited genetic mixing between individuals belonging to different communities within the Indian subcontinent. This suggests a historical trend of relatively isolated genetic groups.
• Endogamous Practices: The prevalence of endogamous practices, such as caste-based, region-based, and consanguineous (closed relatives) marriages, played a significant role in maintaining distinct genetic patterns at the community level.

Impact of Cultural Factors:

• Impact of Ideal Mating Scenario: The study contrasted the observed genetic patterns with an ideal scenario of random mating within a population. In the absence of such random mating, conserved genetic patterns and a higher frequency of certain genetic variants linked to disorders were identified.
• Higher Frequency of Homozygous Genotypes: Compared to a relatively outbred population like that of Taiwan, the South Asian cohort, particularly South-Indian and Pakistani subgroups, exhibited a higher frequency of homozygous genotypes. This could be attributed to cultural factors influencing mate selection.

Inbreeding and Genetic Variants:

• Degree of Inbreeding: The South-Indian and Pakistani subgroups displayed a higher degree of inbreeding, contributing to the observed genetic patterns. In contrast, the Bengali subgroup exhibited lower levels of inbreeding.
• Unique and Disruptive Variants: The study identified a higher number of genetic variants in the South Asian cohort that have the potential to disrupt gene functioning. Additionally, the presence of unique variants not found in European individuals underscores the distinct genetic landscape of the Indian subcontinent.

Health Implications:

• Risk of Disorders: The presence of rare homozygous variants was associated with an increased risk of various disorders, including cardiovascular diseases, diabetes, cancers, and mental disorders. These findings highlight the potential health implications of specific genetic patterns.

-Source: The Hindu