Question

1. A population of rabbits may be brown (the dominant phenotype) or white (the recessive phenotype). Brown rabbits have the genotype BB or Bb. White rabbits have the genotype bb. The frequency of the BB genotype is .35.
a. What is the frequency of heterozygous rabbits?
b. What is the frequency of the B allele?
c. What is the frequency of the b allele?
2. Scale coloration of lizards has a complete dominance relationship where green scales are dominant over blue scales. There are 1,024 individuals with the genotype GG, 512 individuals with the genotype Gg, and 64 individuals with the genotype gg.
a. What is the predicted frequency of heterozygotes?
b. What is the predicted frequency of homozygous dominant?
c. What is the predicted frequency of homozygous recessive?
3. The next generation of lizards has 1092 individuals with green scales and 108 individuals with blue scales. Is the population in Hardy-Weinberg Equilibrium? Solve for p and q.
4. A population of 10,000 humans has 6840 individuals with the blood type AA, 2860 individuals with blood type AB and 300 individuals with the blood type BB.
a. What is the frequency of each genotype in this population? AA= AB= BB=
b. What is the frequency of the A allele?
c. What is the frequency of the B allele?
d. If the next generation contained 25,000 individuals, how many individuals would have blood type BB, assuming the population is in Hardy-Weinberg equilibrium?
5. A population of birds contains 16 animals with red tail feathers and 34 animals with blue tail feathers. Blue tail feathers are the dominant trait.
a. What is the frequency of the red allele?
b. What is the frequency of the blue allele?
c. What is the frequency of heterozygotes?
d. What is the frequency of birds homozygous for the blue allele?
6. Petal coloration of pea plants has a complete dominance relationship where purple petals are dominant over white petals. There are 276 plants, 273 have purple petals.
a. What is the predicted frequency of heterozygotes?
b. What is the predicted frequency of homozygous dominant?
c. What is the predicted frequency of homozygous recessive?
7. The next generation of pea plants has 552 plants, 546 have purple petals. Is the population in Hardy-Weinberg Equilibrium? Solve for p and q.
8. Brown hair (B) is dominant to blond hair (b). If there are 168 brown haired people in a population of 200:
a. What is the predicted frequency of heterozygotes?
b. What is the predicted frequency of homozygous dominant?
c. What is the predicted frequency of homozygous recessive?
9. Sickle-cell anemia is genetic disease where normal homozygous individuals (SS) for the gene have normal blood cells that are easily infected with the malarial parasite. Individuals homozygous for the sickle-cell trait (ss) have red blood cells that easily collapse when deoxygenated, which blocks malaria, but individuals often die because of the genetic defect. However, individuals with the heterozygous condition (Ss) have some sickling of red blood cells so the malaria cannot survive well within these "partially defective" red blood cells. Thus, heterozygotes tend to survive better than either of the homozygous conditions. If 9% of an African population is born with the severe form of sickle-cell anemia (ss), what percentage of the population will be more resistant to malaria because they are heterozygous (Ss) for the sickle-cell gene?
10. The trait for 'male-pattern baldness' is a recessive trait encoded for by "b". Non-balding is encoded for by a dominant allele encoded for by the letter "B". A street survey conducted by Hair Club for Men found that out of 1000 men, 360 had male pattern baldness, the other 480 who did not and were heterozygous, and 160 who did not and were homozygous for a full head of hair.
a. What are the phenotype ratios?
b. Using this information find the allele frequencies for B and b.
c. What are the expected genotype frequencies?

Answer 1

frequency of the dominant allele in the population ... 2pq = frequency of heterozygous individuals. A population of rabbits may be brown (the dominant phenotype) or white (the recessive phenotype). Brown rabbits have the genotype BB or Bb. White rabbits have the genotype bb.