Hardy-Weinberg-Problem Sets Flashcards
Your original population of 200 was hit by a tidal wave and 100 organisms were wiped out, leaving 36 homozygous recessive out of the 100 survivors. If we assume that all individuals were equally likely to be wiped out, how did the tidal wave affect the predicted frequencies of the alleles in the population?
Again, start with the frequency you know – homozygous recessive. Follow the same step-by-step procedure as above. What is the frequency of homozygous recessive?
q2 = (36/100) = 0.36
q = square root of 0.36 = 0.6
What is the predicted frequency of heterozygotes?
frequency of heterozygotes = 2pq
p = 1 - 0.6 = 0.4
frequency of heterozygotes = 2 (0.4)(0.6) = 0.48
What is the predicted frequency of homozygous dominant?
p2 = (0.4)(0.4) = 0.16
Double check:
p2 + 2pq + q2 = 1
0.16 + 0.48 + 0.36 = 1.0
Given that the allele frequencies did change as the result of the tidal wave, we would say that microevolution has occurred. What do we call the phenomenon that caused this evolution?
In a population of 300 individuals, 75 express the recessive phenotype.
- (a) Calculate the frequency of the recessive allele (q).
- (b) Determine the frequency of the dominant allele (p).
- (c) Predict what percentage of the population are heterozygotes.
(a) The frequency of the recessive allele ( q ) is 50%.
(b) The frequency of the dominant allele ( p ) is 50%.
(c) 50% of the population (150 individuals) are heterozygotes.
