Step 1: Understanding the Question:
The question asks for the frequency of heterozygotes in the next generation of a population of moths with given genotype numbers, assuming random mating.
Step 2: Key Formula or Approach:
Under the Hardy-Weinberg principle, allele frequencies in a population can be calculated from genotype numbers.
If $p$ is the frequency of the dominant allele and $q$ is the frequency of the recessive allele:
\[ p = \frac{2 \times N_{AA} + N_{Aa}}{2N} \]
\[ q = \frac{2 \times N_{aa} + N_{Aa}}{2N} \]
After one generation of random mating, the genotype frequencies will reach Hardy-Weinberg equilibrium, where the heterozygote frequency is given by:
\[ f(Aa) = 2pq \]
Step 3: Detailed Explanation:
• We are given a population of $N = 1000$ moths.
• The number of homozygous dominant (brown-colored) moths is $N_{AA} = 450$.
• The number of homozygous recessive (albino) moths is $N_{aa} = 350$.
• The remaining moths are heterozygous, so:
\[ N_{Aa} = 1000 - 450 - 350 = 200 \]
• Let us calculate the allele frequencies:
\[ p = f(A) = \frac{2(450) + 200}{2000} = \frac{900 + 200}{2000} = \frac{1100}{2000} = 0.55 \]
\[ q = f(a) = \frac{2(350) + 200}{2000} = \frac{700 + 200}{2000} = \frac{900}{2000} = 0.45 \]
• Now, assuming random mating occurs, the population will establish Hardy-Weinberg equilibrium in the next generation.
• The expected frequency of heterozygous individuals ($Aa$) in the next generation is:
\[ f(Aa) = 2pq = 2 \times 0.55 \times 0.45 = 0.495 \]
Step 4: Final Answer:
Therefore, the frequency of heterozygotes in the next generation will be 0.495.