In a multiple allelic system with 3 alleles (A1, A2 and A3), if the frequency of A1 = 0.25 and A2 = 0.35, what is the frequency of A3?
Options
0.35
0.10
0.25
0.40 ✓
Correct Answer: D
Explanation in English
Correct Answer: 0.40
From the notes: Sum total of gene frequencies of all alleles at one locus must equal 1.
Calculation
A1 + A2 + A3 = 1
0.25 + 0.35 + A3 = 1
A3 = 1 − 0.25 − 0.35 = 0.40
Multiple Allelism (from notes)
More than two alternative forms of a gene at the same locus
Multiple alleles are produced by mutation
Present in the population, NOT in a single individual
Possible genotypes = N(N+1)/2, where N = number of alleles
With 3 alleles: 3(4)/2 = 6 possible genotypes
Examples (from notes)
ABO blood group in humans: 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.
