Human Genetics & Population Studies: Notes & PYQs | UPSC Anthropology

What is Human Genetics in Anthropology?

Human Genetics in physical anthropology studies the patterns of inheritance, genetic variation, and evolutionary mechanisms across human populations. It bridges biological anthropology with population genetics to examine how processes like mutation, natural selection, gene flow, and genetic drift alter allele frequencies over generations.

Forces Changing Allele Frequencies in Populations

Mechanism	Definition	Impact on Population Genetics
Hardy-Weinberg Equilibrium	States that allele frequencies remain constant in a large, randomly mating population without evolutionary forces.	Serves as a baseline model ($p^2 + 2pq + q^2 = 1$) to detect evolutionary changes.
Genetic Drift	Random fluctuations in allele frequencies, especially pronounced in small, isolated populations.	Includes Founder Effect and Bottleneck Effect; reduces genetic variation.
Gene Flow	Transfer of genetic material between separate populations through migration and interbreeding.	Increases genetic diversity within populations while reducing differences between them.
Genetic Polymorphism	Occurrence of two or more clearly different phenotypes in the same population (e.g., ABO blood groups).	Maintains adaptive diversity (balanced polymorphism, e.g., Sickle Cell trait & Malaria resistance).

Population Genetics Answer Diagram Schematic:

[Original Gene Pool (Allele Frequencies p & q)]
    ↓ (Disrupted by Evolutionary Forces)
+-----------------+-----------------+-----------------+
| | | |
[Mutation] [Natural Selection] [Gene Flow] [Genetic Drift]
| | | |
+-----------------+-----------------+-----------------+
    ↓
[Altered Allele Frequencies (Microevolution)]

Applications of Genetic Studies in Anthropology

• Mapping Human Migration: Analyzing mitochondrial DNA (mtDNA) and Y-chromosome markers to trace ancient human expansion routes out of Africa.
• Consanguinity & Inbreeding Studies: Evaluating the genetic load, recessive disease expression, and isolation impacts in endogamous Indian caste and tribal populations.
• Disease Susceptibility & Adaptation: Studying balanced polymorphism (e.g., Sickle cell allele in malaria-endemic tribal belts of Central India).

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