Question

In Hardy–Weinberg equilibrium, the sum of gene frequencies is: ____.

• A. 0
• B. 1
• C. 2
• D. 100

Hint:

While $p + q = 1$ is for allele (gene) frequencies, the formula for genotype frequencies is $p^2 + 2pq + q^2 = 1$. In both cases, the sum is always 1!

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.

Step 2: Key Formula or Approach:
In a population with only two alleles for a gene (dominant $p$ and recessive $q$), the sum of the allele frequencies must account for 100% of the population. \[ p + q = 1 \]

Step 3: Detailed Explanation:
Since $p$ represents the frequency of the dominant allele and $q$ represents the frequency of the recessive allele, they are expressed as decimals. Because there are no other options for that gene in this model, their combined frequency must equal the total population, which is represented as 1 (or 100%).

Step 4: Final Answer:
The sum of gene frequencies in Hardy-Weinberg equilibrium is 1.