Question

Normal pigmentation dominates no pigmentation (albino). For an organism to exhibit color, it must have an allele for normal pigment production as well as alleles for a specific color. In cattle, red color dominates black color. An albino bull that has a heterozygous genotype for red is crossed with a red cow. The cow is heterozygous for normal pigment production and for red coloring. What types of offspring will they produce, and what is the probability of producing these types of offspring

Answer 1

Answer and Explanation:

Available data:

• Normal pigmentation dominates no pigmentation (albino)
• Red color dominates the black color
• For an organism to exhibit color, it must have an allele for normal pigment production as well as alleles for a specific color

Let us say that the P allele expresses color, while the p allele expresses albinism.

Let us also say that the R allele expresses red color, while the r allele expresses black color.

Cross: An albino, heterozygote for red bull is crossed with a heterozygous red cow

Parental) pp Rr x Pp Rr

Gametes) pR pr pR pr PR pR Pr pr

Punnet square) pR pr pR pr

PR PpRR PpRr PpRR PpRr

pR ppRR ppRr ppRR ppRr

Pr PpRr Pprr PpRr Pprr

pr ppRr pprr ppRr pprr

F1) Genotype:

• 2/16 PpRR;

• 2/16 ppRR;

• 4/16 PpRr;

• 4/16 ppRr;

• 2/16 Pprr;

• 2/16 pprr

Phenotype:

• 8/16 Albino (ppRR + ppRr + pprr)

• 6/16 Red pigmented (PpRR + PpRr)

• 2/16 Black pigmented (Pprr)