Gene Frequency Calculation in Multiple Allelic System
In a multiple allelic system with 3 alleles (A₁, A₂, A₃), if frequency of A₁ = 0.25 and frequency of A₂ = 0.35, what is the frequency of A₃?
- 0.25
- 0.35
- 0.10
- 0.40 — Correct Answer
Explanation:
Correct Answer: 0.40
The sum of frequencies of all alleles at one locus must equal 1.
A₁ + A₂ + A₃ = 1
0.25 + 0.35 + A₃ = 1
A₃ = 1 − 0.60 = 0.40
Multiple Allelism — Key Facts
- More than two alternative forms of a gene located on the same locus of homologous chromosomes.
- Multiple alleles are produced by mutation.
- Found in the population, not in a single individual.
- No. of possible genotypes = N(N+1)/2, where N = no. of alleles.
Examples
- ABO blood group in human: 3 alleles (Iᴬ, Iᴮ, Iᴼ)
- Coat colour in Rabbit: 4 alleles
- Eye colour in Drosophila: 15 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.
