Question

Ellis-van Creveld syndrome is a recessive genetic disorder that includes the characteristics of short stature and extra fingers or toes. In the general population, this syndrome occurs in approximately 1 in 150,000 live births. In a particular isolated population, however, the incidence of this syndrome among live births is 1 in 500.Assume that both the isolated population and the general population are in Hardy-Weinberg equilibrium with respect to this syndrome. Which of the following best describes the difference between the frequency of the allele that causes the syndrome in the general population and the frequency of the allele in the isolated population?A. The frequency of the Ellis-van Creveld allele is 0.002 in the isolated population and 0.0000066 in the general population,which suggests that selection for this trait is occurring in both populations.B. The frequency of the Ellis-van Creveld allele is 0.0447 in the isolated population and 0.0026 in the general population, showing that the rate of genetic mutation is highest among individuals in the isolated population.C. The frequency of the Ellis-van Creveld allele is 0.002 in the isolated population and 0.0000066 in the general population, which demonstrates gametic incompatibility between the populations.D. The frequency of the Ellis-van Creveld allele is 0.0447 in the isolated population and 0.0026 in the general population, which suggests that genetic drift has occurred in the isolated population.

Answer 1

Answer:

D. The frequency of the Ellis-van Creveld allele is 0.0447 in the isolated population and 0.0026 in the general population, which suggests that genetic drift has occurred in the isolated population.

Explanation:

If we assume that one gene is involved in Ellis-van Creveld syndrome and we name that gene with A, then the genotype of the syndrome would be aa.

In population 1, the frequency of the syndrome is 1/150000=0.0000066(it is the frequency of the aa gentotype)

In population 2, the frequency of the syndrome is 1/500=0.002

According to Hardy-Weinberg equilibrium

p2+2pq+q2=1 (p2 is the frequency of the dominant homozygous, 2pq is the frequency of heterozygous and q2 is the frequency of the recessive homozygous).

q or the frequency of the Ellis-van Creveld allele in Population 1 is $\sqrt{0.0000066}$ =0.0026

q or the frequency of the Ellis-van Creveld allele in Population 2 is $\sqrt{0.002}$ = 0.0447