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Read Gamete Variety from Heterozygous Loci
Independent heterozygous loci multiply the number of possible gamete combinations.
NSEB · Principles of Inheritance and Variation · 3 linked questions · 100% coverage
Know this first
Independent Assortment is the central idea in this question pattern. Identify the condition in the stem before applying the method below.
Study deeper: NCERT Biology · Principles of Inheritance and Variation
Count the heterozygous pairs
If n loci are heterozygous and assort independently, the number of gamete types is 2^n. Homozygous loci contribute no choice.
Count combinations from chromosome pairs
Independent assortment produces 2^n possible chromosome combinations in gametes, where n is the haploid number of chromosome pairs. For three pairs there are eight; for humans with 23 pairs there are 2²³, even before crossing-over.
OlympIQ exam lens
- ✓Count heterozygous loci only.
- ✓Gamete types = 2^n.
- ✓Independent-assortment combinations = 2^n.
- ✓Use chromosome-pair number, not total chromosome number.
OlympIQ trap
A genotype with more total genes is not necessarily more gamete-diverse; count heterozygous pairs.
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