Genetic Risk Analysis

Question 1

Albinism is a

Answer 1

recessive trait

Question 2

Sickle cell anemia

Answer 2

1/600 births in African-Americans; rarely in Northern Europeans

Question 3

Cystic Fibrosis

Answer 3

Autosomal recessive - 1/2500 births in Caucasians; 1/90000 in Asians (1 in 3300 in US)

Question 4

Phenotype Ratio vs Genotype Ratio

Answer 4

3:1 vs 1:2:1

Question 5

In a dihybrid cross AaDd x AaDd there are ___ genotypes possible and ___ phenotypes possible

Answer 5

9; 4

Question 6

CFTR

Answer 6

Cystic Fibrosis gene, 900 different mutations described, cAMP regulated Cl channel (dehydration and thickening mucus)

Question 7

Carrier frequency of CF in caucasians?

Answer 7

1/2500 have CF (recessive) = q^2; q = 0.02
p^2 + 2pq + q^2 = 1
p + q = 1
2pq = 0.04 or 1/25

Question 8

Hardy Weinberg Principle

Answer 8

relationship between gene and genotype frequency; used to calculate allele/gene frequencies when 1 or more alleles produces a recessive trait in a population that meets certain criteria

Question 9

Criteria for Hardy Weinberg

Answer 9

Large population, no natural selection, random mating, negligible mutation rate