Question

1a. In dogs, a Dominant gene (H) produces a wire-haired texture. The Recessive allele (h) produces smooth hair. A Homozygous wired-haired male is mated to a female with smooth hair. What are the genotypes of the parents? *

Male = HH
Male = Hh
Male = hh
Female = HH
Female = Hh
Female = hh
1b. In dogs, a Dominant gene (H) produces a wire-haired texture. The Recessive allele (h) produces smooth hair. A Homozygous wired-haired male is mated to a female with smooth hair. What are the genotypes of the offspring? *
HH
Hh
hh
1c. In dogs, a Dominant gene (H) produces a wire-haired texture. The Recessive allele (h) produces smooth hair. A Homozygous wired-haired male is mated to a female with smooth hair. What are the phenotypes of the offspring? *
Wired Haired
Smooth Haired
Wavy Haired
2a. Brown fur (B) is dominant to white fur (b) in rabbits. Two Heterozygous rabbits are mated. What are the genotypes of the parents? *
Male Parent = BB
Male Parent = Bb
Male Parent = bb
Female Parent = BB
Female Parent = Bb
Female Parent = bb
2b. Brown fur (B) is dominant to white fur (b) in rabbits. Two heterozygous rabbits are mated. What are the expected phenotypes and in what percentages will be the offspring? *
25% Brown, 50% Tan, and 25% White
75% Brown and 25% White
25% Brown and 75% White
50% Brown and 50% White
100% Tan
3a. The Common Grackle is a species of medium sized blackbirds prevalent all over the country. In grackles Long tails (L) are dominant to short tails (l). A female short tailed grackle mates with a long tailed male grackle who had one parent with a short tail. What is the genotype of the male grackle? *
LL
Ll
ll
3b. The Common Grackle is a species of medium sized blackbirds prevalent all over the country. In grackles Long tails (L) are dominant to short tails (l). A female short tailed grackle mates with a long tailed male grackle who had one parent with a short tail. What will the genotypes and in what percentages be for the offspring of these two grackle parents *
100% LL
75% LL and 25% ll
50% Ll and 50% ll
50% LL and 50% Ll
100% Ll
4a. The ability to curl your tongue (T) is dominant to not being able to curl your tongue (t). A woman who can roll her tongue marries a man who cannot roll his tongue. Their first child has his father's phenotype. What are the genotypes of the parents? *
Woman = TT
Woman = Tt
Woman = tt
Man = TT
Man = Tt
Man - tt
4b. The ability to curl your tongue (T) is dominant to not being able to curl your tongue (t). A woman who can roll her tongue marries a man who cannot roll his tongue. Their first child has his father's phenotype. What are the chances their 2nd child will be able to roll its tongue? *
25%
50%
75%
100%
5. In sheep, White wool (T) is dominant over Black Wool (t). Two heterozygous sheep are crossed. What percentage of the white lambs will be heterozygous? *

Answer 1

1a. Male- HH, female- hh

1b. Hh

1c. Wired haired

2a. Male parent-Bb, Female parent- Bb

2b. 75% brown, 25% white

3a. Ll

3b. 50% Ll and 50% ll

4a. Woman- Tt, Man- tt

4b. 50%

5. 50%

Step-by-step explanation:

1a. According to the question, a dominant allele (H) produces a wire-haired texture while the recessive allele (h) produces smooth hair texture. A homozygous wired-haired male means he has same alleles for the dominant trait, hence, will possess the genotype: HH while the female with smooth hair will have a genotype: hh since the recessive trait will only be expressed in a homozygous recessive condition.

1b. A Homozygous wired-haired male (HH) is mated to a female with smooth hair (hh), all their offsprings will have an heterozygous genotype: Hh

1c. Since the offsprings have a Hh genotype, they will be phenotypically wired haired because the allele for wired hair (H) will mask the phenotypic expression of the smooth hair allele (h).

2a. According to the question, Brown fur allele (B) is dominant to white fur allele (b) in rabbits. Heterozygous rabbits contains a combination of both dominant and recessive alleles i.e. Bb. Hence, if both parents are heterozygous, they will have a genotype: Bb.

2b. If the two heterozygous rabbits (Bb) are mated, four possible offsprings will be produced with genotypes; BB, Bb, Bb and bb. Genotypes BB, Bb and Bb (3) are phenotypically brown furred while genotype bb (1) is phenotypically white furred. Hence, the phenotypic ratio of brown to white offsprings is 3:1. In percentage, we have 3/4 × 100 = 75% for brown offsprings while 1/4 × 100= 25% for white offsprings.

3a. Based on the question, long tails (L) are dominant to short tails (l) in grackles. A long tailed male grackle who had one parent with a short tail will have genotype: Ll because the parent with the recessive trait (short tail) will contribute the recessive allele, which will be carried by the offspring even if the male is phenotypically long-tailed.

3b. If a female short tailed grackle (ll) mates with a long tailed male grackle (Ll) who had one parent with a short tail, offsprings Ll and ll will be produced in a ratio 1:1. Hence, 1/2 or 50% of genotype Ll and ll respectively will be produced by the cross.

4a. According to this question, the ability to curl your tongue (T) is dominant to not being able to curl your tongue (t). If a cross between a woman who can roll her tongue and a man who cannot roll his tongue (tt) produces an offspring who cannot roll his tongue (tt), it means the dominant female is heterozygous i.e. contains both dominant and recessive alleles (Tt). Hence, the genotype of the female parent is Tt while that of the male parent is tt.

4b. A cross between a Tt female and a tt male will produce Tt and tt offsprings in the ratio 1:1. Tt offsprings can roll their tongue while tt can't. The probability of producing an offspring that can roll his/her tongue will be 1/2 × 100 = 50%.

5. According to this question, white wool (T) is dominant over Black Wool (t) in sheeps. This means that heterozygous sheep will possess a genotype; Tt. If two heterozygous sheeps (Tt) are crossed, offsprings with the genotypes; TT (1), Tt (2) and tt (1) will be produced in a ratio 1:2:1. The TT and Tt genotypes will be white. Hence, the probability of producing an offspring that is heterozygous (Tt) for the white trait is 2/4 × 100 = 50%.