ASG 3313

Problem Set 3

1. You are superovulating your black, solid (nonspotted), polled Simmental cow which you know to be heterozygous for all three loci and breeding her to a bull which is known to be homozygous black and heterozygous for the other two loci. Determine the following:

a. The frequencies of calves of each phenotype from the above mating (use the fork-line method).

b. The probability of nonspotted, black polled calves (use the probability method).

c. The probability of calves homozygous for the black, nonspotted and the polled loci.

2. You are superovulating a cow of genotype E^deS^PsBrbr⁺ (Holstein × Pinzgauer crossbred) and breeding her to a bull of genotype E⁺eS^hS⁺Brbr⁺ Hereford × Brahman crossbred). Determine the following:

a. The probability that a nonspotted brindle calf will occur;

b. that a red calf with a restricted Pinzgauer pattern will occur.

Answers to Problem Set 3

1. Bull Genotype: E^dE^dS⁺sPp⁺ Cow Genotype: E^deS⁺SPp⁺

a. 3/4 P_ 9/16 Black, solid, polled

3/4 S⁺_

1/4 p⁺p⁺ 3/16 Black, solid, horned

E^d_

3/4 P_ 3/16 Black, spotted, polled

1/4 ss 1/4 p⁺p⁺ 1/16 Black, spotted, horned

b. P (Black) × P (solid) × P (Polled) =

1 × 3/4 × 3/4 = 9/16

c. P (Homozygous Black) × P (Homozygous solid) × P (Homozygous polled) =

1/2 × 1/4 × 1/4 = .03125

2. Bull Genotype: E⁺eS^hS⁺Brbr⁺ Cow Genotype: E^deS^PsBrbr⁺

a. P (nonspotted brindle) P(E⁺e) . P(S⁺s) . P(Br_) = 1/4 . 1/4 . 3/4 = 3/64

b. P (red, restricted Pinzgauer) = P(ee) . P(S^PS⁺) . P(BrBr or Brbr+ or br+br+)

= 1/4 . 1/4 . 1 = 1/16