Consider the following statements: DNA Barcoding can be a tool to:assess the age of a plant or anima

Q: What is UPSC Prelims?

UPSC Prelims is a competitive examination conducted in India. This question is from the 2022 UPSC Prelims Science & Technology paper.

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Question

Consider the following statements: DNA Barcoding can be a tool to:assess the age of a plant or animal.distinguish among species that look alike.identify undesirable animal or plant materials in processed foods.Which of the statements given above is/are correct?

Accepted Answer

Correct Answer: D — 2 and 3Step-by-step Solution:DNA Barcoding is a method of species identification that uses a short, standardised region of DNA (typically the mitochondrial COI gene for animals, or rbcL/matK genes for plants) to identify species. Just as a supermarket barcode identifies a product, a DNA barcode identifies a species by comparing its characteristic DNA sequence against a reference library.Statement 1 — DNA barcoding can assess the age of a plant or animal: This is incorrect. DNA barcoding identifies species — it does NOT assess the age of an individual organism. Determining age uses different methods: growth rings in trees (dendrochronology), wear on teeth, bone density, carbon dating for fossils. DNA barcoding is about species identification, not age determination. ✗Statement 2 — DNA barcoding distinguishes among species that look alike (cryptic species): This is correct. One of the most powerful applications of DNA barcoding is distinguishing between cryptic species — species that are morphologically similar (look alike) but are genetically distinct. For example: distinguishing among similar-looking butterfly and moth species (Lepidoptera); identifying different frog species that look similar; distinguishing fish species in the market. DNA barcoding has been successfully used to identify new cryptic species in tropical regions. ✓Statement 3 — DNA barcoding identifies undesirable materials in processed foods: This is correct. DNA barcoding is used for food authenticity testing — detecting adulteration or mislabelling in food products. For example: identifying cheaper fish species substituted for expensive ones (seafood fraud is widespread globally); detecting undeclared animal products in processed foods; identifying plant adulterants in herbal products; detecting contaminants in exported food items. A notable case involved roasted barley tea exported from China containing undesirable plant contaminants detected by DNA barcoding. ✓Why other options are incorrect:Options A, B, and C: Incorrect because statement 1 is wrong.Key Concept: DNA barcoding applications: Species identification and discovery; cryptic species differentiation; food authenticity (fraud detection); wildlife crime investigation (identifying poached species from confiscated products); invasive species monitoring; environmental DNA (eDNA) analysis from water, soil, air samples. India application: DNA barcoding used to identify new frog species in Kerala and Western Ghats; wildlife forensics (Tiger, Elephant identification). BOLD Systems (Barcode of Life Data Systems) is the global reference library for DNA barcodes.

Consider the following statements: DNA Barcoding can be a tool to:assess the age of a plant or animal.distinguish among species that look alike.identify undesirable animal or plant materials in processed foods.Which of the statements given above is/are correct?

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Consider the following statements: DNA Barcoding can be a tool to:assess the age of a plant or animal.distinguish among species that look alike.identify undesirable animal or plant materials in processed foods.Which of the statements given above is/are correct?

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More Questions from Biotechnology – GMOs, Gene Editing & CRISPR

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