Question

Suppose that a dominant allele (P) codes for a polka-dot tail and a recessive allele (p) codes for a solid colored tail. If two heterozygous individuals with polka-dot tails mate, what's the probability of the phenotype and genotype combinations of the offspring?
A. 25 percent chance of a polka-dot tail and 75 percent chance of a solid colored tail (25 percent PP; 50 percent Pp; 25 percent pp)
B. 50 percent chance of a polka-dot tail and 50 percent chance of a solid colored tail (50 percent PP; 50 percent pp)
C. 75 percent chance of a polka-dot tail and 25 percent chance of a solid colored tail (25 percent PP; 50 percent Pp; 25 percent pp)
D. 75 percent chance of a polka-dot tail and 25 percent chance of a solid colored tail (75 percent Pp; 25 percent pp)

Answer 1

The correct answer is C. As Pp (heterozygous allele) crosses with Pp( another heterozygous allele), the resultant genotypes would be PP, Pp, Pp, pp. This confirms that 25 percent of the population would be homozygous polka-dotted, another 25 would be homozygous solid colored, and rest of the 50 percent would be heterozygous polka. Thus, a total of 75 percent would be polka-dotted.