Revision summary
Expression is transcription plus translation under regulatory control. Crick’s central dogma names the default flow from DNA to protein. Enhancers, chromatin, and splicing decide cell-specific products. Lactase persistence and Tibetan EPAS1 are anthropological examples of regulatory change. Epigenetic marks link environment to expression without rewriting the DNA code.
Model answer
Copper italics in this answer — like this — are the key facts. Each one is unpacked in the Facts & figures rail.
Introduction
Gene expression is the turning of DNA sequence into RNA and protein at the right time and place. A genotype is not a finished trait until this switchboard has worked.
Body
The process
- Transcription copies a gene into messenger RNA, and translation at the ribosome builds a polypeptide, which Francis Crick placed in the central dogma of molecular biology.
- Promoters, enhancers, transcription factors, and chromatin packing decide which loci are on in a liver cell and off in a neuron.
- Alternative splicing and RNA editing can make more than one product from one locus, so one-gene-one-trait talk is too crude for anthropology.
Why anthropologists need it
- Lactase persistence is a regulatory change near the lactase gene, not a new digestive organ, which is why dairying cultures and genotype must be read together, as in European and some African pastoral histories.
- High-altitude EPAS1 regulation in Tibetans, and methylation changes under famine or stress, show expression and epigenetics as part of human adaptation.
- Disease risk, growth, and pigmentation are therefore expression profiles in environments, not a fixed racial essence.
Flow diagram
Conclusion
Gene expression is regulated transcription and translation, not the mere presence of a locus. Human variation in diet, altitude, and disease is often a story of when genes are on.
Quick related
Students also ask
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Elucidate the different forms of malnutrition. Describe protein-calorie malnutrition with suitable examples.
Next question on this syllabus topic (2023 · Q2(c)). View answer →
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Is gene expression the same as genotype?
No. Genotype is the sequence. Expression is whether and how that sequence is used in a tissue and an environment.
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Why does this appear in biological anthropology?
Because adaptation, growth, and disease often sit in regulation, not in a new protein invented from nothing.
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Q2(c) · UPSC Mains 2023 · Anthropology GS 1 · 15 marks · Solution
Elucidate the different forms of malnutrition. Describe protein-calorie malnutrition with suitable examples.
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