📘 Q13. IAS Prelims 2022 — Science & Technology (DNA Barcoding)
🧷 Authentic Classroom Explanation by IAS Monk
📌 The Question
Consider the following statements:
- DNA barcoding can be a tool to assess the age of a plant or animal.
- DNA barcoding can be used to distinguish among species that look alike.
- DNA barcoding can be used to identify undesirable animal or plant materials in processed foods.
Which of the statements given above is/are correct?
(a) 1 only
(b) 3 only
(c) 1 and 2
(d) 2 and 3
✅ Answer
(d)
🧑🏫 Classroom Explanation
- Statement 1 is not correct
DNA barcoding identifies species using a short, standardized DNA sequence. It does not determine age of an organism. - Statement 2 is correct
DNA barcoding is highly effective in distinguishing morphologically similar species. It has been widely used in groups like butterflies and moths (Lepidoptera), where visual identification is difficult. - Statement 3 is correct
DNA barcoding is extensively used in food authentication. It helps detect:- Undeclared or substituted species in seafood and meat products
- Undesirable plant or animal material in processed foods (e.g., tea, spices, herbal products)
Hence, statements 2 and 3 are correct.
🔍 Curiosity Raiser
Ever wondered how authorities catch food fraud when the sample is powdered, cooked, or processed?
DNA barcoding still works even when no visible biological features remain.
📚 Enrichment Notes
- Common barcode genes:
- COI gene in animals
- rbcL and matK genes in plants
- Widely used in:
- Wildlife forensics
- Conservation biology
- Customs and trade regulation
- Builds global reference libraries like BOLD (Barcode of Life Data System)
🪔 IAS Monk Whisper
“When appearances deceive, DNA speaks the truth.”