Understanding the Basics
* Allele Frequency: The proportion of a specific allele in a population. You're given that the frequency of allele B is 0.7. This means the frequency of allele b is 0.3 (since allele frequencies must add up to 1).
* Genotype Frequency: The proportion of individuals in a population with a specific genotype (like Bb).
Hardy-Weinberg Equilibrium
To calculate genotypic frequencies, we use the Hardy-Weinberg Principle, which describes the relationship between allele and genotype frequencies in a population that's not evolving. The key equations are:
* p + q = 1 (where p is the frequency of allele B, and q is the frequency of allele b)
* p² + 2pq + q² = 1 (where p² is the frequency of BB, 2pq is the frequency of Bb, and q² is the frequency of bb)
Calculation
1. Find the frequency of Bb (2pq):
* p = 0.7
* q = 0.3
* 2pq = 2 * 0.7 * 0.3 = 0.42
Answer: The genotypic frequency of heterozygotes (Bb) is 0.42, or 42%.
