Primary Cause of Genetic Variation
Biggest cause of genetic variation-
- Segregation — Correct Answer
- Crossing over
- Selection
- None
Explanation:
Correct Answer: Segregation
Segregation (Mendel's First Law — Law of Purity of Gametes) is the biggest ongoing cause of genetic variation. Every meiotic division reshuffles alleles into new combinations, continuously generating genetic diversity in offspring every generation.
Causes of Genetic Variation — Ranking
| Rank | Cause | Mechanism |
|---|---|---|
| 1st (Biggest) | Segregation | Alleles separate into gametes during meiosis → billions of new genotypic combinations possible in each generation |
| 2nd | Crossing over | Exchange of segments between homologous chromosomes at Pachytene stage → new allelic combinations on chromosomes |
| 3rd | Mutation | Ultimate source of ALL new alleles; but rate is very slow (10⁻⁵ to 10⁻⁶ per locus per generation) |
| Others | Migration, Selection, Genetic drift | Alter frequencies of existing variation rather than creating new alleles |
📚 About this Topic — Animal Genetics & Breeding
This multiple choice question is from Animal Genetics & Breeding, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Genetics & Breeding to strengthen your preparation.
