Prelims 2011 · archive
MediumAt present, scientists can determine the arrangement or relative positions of genes or DNA sequences on a chromosome. How does this knowledge benefit us?
- 1.It is possible to know the pedigree of livestock.
- 2.It is possible to understand the causes of all human diseases.
- 3.It is possible to develop disease-resistant animal breeds.
Which of the statements given above is/are correct?
Answer & explanation
Answer: (c) 1 and 3 only
Once genes and DNA markers are placed on chromosomes, they can be used to trace parentage in livestock and to select animals carrying disease-resistance genes. The claim that this explains the causes of all human diseases is false. Many diseases are caused by pathogens, poor nutrition or an unhealthy lifestyle, not by a defective gene alone.
- ✓ 1. Mapped DNA markers such as autosomal microsatellites are commonly used for individual genetic identification and parentage analysis in livestock. This is how an animal's pedigree is established.
- ✗ 2. The word 'all' makes this wrong. Many human diseases are caused by germs (bacteria, viruses, fungi, worms or protozoa), by poor nutrition or by an unhealthy lifestyle. Gene mapping can explain only the genetic part of disease.
- ✓ 3. Mapped markers linked to useful traits are used in marker-assisted selection. This makes it easier for breeders to select animals for disease resistance and so develop disease-resistant breeds.
Remember · Gene and marker mapping helps in parentage testing and in breeding for disease resistance. It cannot explain all human diseases, because pathogens, nutrition and lifestyle also cause disease.
📘 Read it in NCERT: Class 8 Curiosity, Ch 3 (practise this chapter)
Sources
- FAO – The Role of Biotechnology in Exploring and Protecting Agricultural Genetic Resources (genetic markers and livestock) ↗ “Autosomal microsatellite loci will be commonly used for individual genetic identification and parentage analysis”
- FAO – Marker-assisted selection in livestock (Section III) ↗ “Hence, while it will be easier to select for carcass and disease resistance”
- NCERT Class 8 · Curiosity, Chapter 3 “Some diseases are caused by germs like bacteria, viruses, fungi, worms, or even by protozoa (single-celled organisms). These disease-causing organisms are called pathogens. Other diseases may result from poor nutrition or an unhealthy lifestyle.”
Question: UPSC Civil Services (Preliminary) 2011, General Studies paper. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·