Revision summary
A genetic marker is a heritable polymorphism that can be read in families or populations. Classical markers include ABO and proteins. DNA markers include SNPs, STRs, mtDNA and Y haplotypes. Population applications map variation and movement and undermine typological race. Disease applications include sickle-cell and malaria, HLA, counselling, and GWAS. Forensic applications include STR identification, mtDNA from degraded samples, and Y-lineage in mixtures. Lewontin’s within-group diversity and Jeffreys’s DNA fingerprinting are central names.
Model answer
Introduction
A genetic marker is a measurable hereditary character that differs among individuals and can be followed in families or populations. It may be a classical blood-group antigen, a protein variant, or a DNA site such as a SNP or STR. Markers are tools. They are not the same thing as a ‘race gene’.
Body
What counts as a marker
Classical markers include ABO and Rh blood groups, HLA types, and protein polymorphisms. Karl Landsteiner’s ABO system is still the first standard example. DNA markers now dominate: single-nucleotide polymorphisms (SNPs), short tandem repeats (STRs), mitochondrial haplogroups, and Y-chromosome haplotypes. Alec Jeffreys made hypervariable DNA useful as a fingerprint. L. L. Cavalli-Sforza organised classical and then molecular markers into maps of population history. Richard Lewontin used similar variation to show that most genetic diversity is within groups, not between continental labels.
- A good definition: a marker is polymorphic, heritable, and readable in the lab or the pedigree.
Population variation
- Markers describe structure: allele frequencies, genetic distance, and clines. They helped replace typological race with population thinking. Indian anthropology used ABO, MN, PTC and later DNA to study caste, tribe and regional diversity as overlapping frequencies, not as sealed types. mtDNA and Y-chromosome markers add sex-specific histories of movement. The ethical warning is the same as for mtDNA: a haplogroup is not a civilisation.
Disease association
Some markers sit in or near genes that affect disease. Sickle-cell haemoglobin and malaria is the classic anthropological case (A. C. Allison). HLA associations with autoimmune disease, and later SNP associations, including GWAS, extend the same logic. Markers also guide counselling when they track a Mendelian locus in a pedigree.
Association is not always causation. Linkage disequilibrium can flag a neighbour gene. Population structure can produce false links if cases and controls are poorly matched.
Forensics
STRs from several loci identify individuals with high discrimination when the sample is good. Markers also exclude suspects and identify remains after disasters. mtDNA helps when hair shafts or degraded bone yield little nuclear DNA, because many copies exist per cell. Y markers can track a paternal line in sexual-assault mixtures. Forensic anthropology still needs bones, context and consent. DNA does not replace osteology.
DNA testing of unidentified dead, or in disputed paternity, is a public application of the same methods.
Flow diagram
flowchart TD G[Genetic markers] --> P[Population variation] G --> D[Disease association] G --> F[Forensics] P --> C[Frequencies not races] D --> S[Sickle cell / GWAS] F --> T[STRs and mtDNA]
Conclusion
Genetic markers are heritable polymorphisms used as instruments. In populations they map variation and history. In medicine they flag disease risk and Mendelian loci. In forensics they identify and exclude. Landsteiner, Jeffreys, Cavalli-Sforza and Lewontin mark the path from blood groups to DNA, and race typology does not follow from markers.
Quick related
Students also ask
-
Examine the utility of human remains in forensic analysis. Discuss the facial reconstruction technique
Next question on this syllabus topic (2025 · Q8(c)). View answer →
-
Are blood groups outdated as markers?
They are no longer the frontier, but they still illustrate Mendelism and early population surveys. DNA markers now lead, with classical ones as history and pedagogy.
-
Can markers prove caste origins?
They can describe average affinities and movements. They cannot certify a mythic origin story.
PYQ trend
When UPSC asked this
Related PYQs from other years, newest first. Open a question to read it.
-
2025 · Q3(a) · Anthropology GS 1 · 20 marks
How anthropologists assess the nutritional status of a community? Discuss the significance of intersectionality of ecology, culture, and social inequality in the study of nutritional anthropology -
2025 · Q4(a) · Anthropology GS 1 · 20 marks
Anthropology provides a multidimensional understanding of human beings by bridging the gap between science and humanities. Elucidate -
2025 · Q8(c) · Anthropology GS 1 · 15 marks
Examine the utility of human remains in forensic analysis. Discuss the facial reconstruction technique -
2024 · Q6(b) · Anthropology GS 1 · 15 marks
Discuss the applications of forensic anthropology with suitable examples. -
2023 · Q4(b) · Anthropology GS 1 · 15 marks
Discuss various methods of personal identification based on skeletal remains. -
2023 · Q6(c) · Anthropology GS 1 · 15 marks
Describe the practical applications of DNA technology in the current scenario. -
2022 · Q5(b) · Anthropology GS 1 · 10 marks
Genetic imprinting in human diseases -
2022 · Q8(c) · Anthropology GS 1 · 15 marks
Discuss how anthropological knowledge of the human body may be used in designing equipments and articles of human use
More from this topic
Q8(c) · UPSC Mains 2025 · Anthropology GS 1 · 15 marks
Examine the utility of human remains in forensic analysis. Discuss the facial reconstruction technique
Applications of Anthropology
Forensic anthropology estimates sex, age, stature and trauma from bones and teeth, and it records context. Krogman and Stewart standardised osteological identification. DNA STRs and dentistry confirm identity when references exist. Clyde Snow’s human-rights cases show remains as testimony. Facial reconstruction uses tissue-depth markers, as in Gerasimov and Gatliff, now often with CT and 3D prints. The face is an approximation to prompt recognition, not a certain portrait. Ethics include family consent and no racial or caste over-claim.
Q4(a) · UPSC Mains 2025 · Anthropology GS 1 · 20 marks
Anthropology provides a multidimensional understanding of human beings by bridging the gap between science and humanities. Elucidate
Applications of Anthropology
Anthropology studies one species as organism and as meaning-maker. The science side is palaeoanthropology, genetics, anthropometry and dating. The humanities side is ethnography, ritual, kinship and interpretation, as in Geertz. The bridge is biocultural questions such as nutrition, forensics, language and embodiment. The two failures are reductionism and culturalism. Fossils and symbols belong in one understanding of the human.
Q3(a) · UPSC Mains 2025 · Anthropology GS 1 · 20 marks
How anthropologists assess the nutritional status of a community? Discuss the significance of intersectionality of ecology, culture, and social inequality in the study of nutritional anthropology
Applications of Anthropology
Assess with stunting, wasting, underweight, MUAC and BMI, plus diet recall and a seasonal calendar, plus clinical or lab signs where possible. Always add ethnography of who eats what. Community averages are not community status. Disaggregate by class, caste, tribe and gender. Ecology is season, infection and soils. Culture is taboos, feeding rules and sharing. Inequality is class, caste, gender and displacement. Intersection is drought times landlessness times gendered plates. Intervention follows the join, not nutrition education alone.
Toppers' copies
Toppers' copies for this question will be uploaded soon.