Question

biologists have found that a form of deafness is a recessive trait in dogs. if a female dog that is heterozygous for the trait mates with a male dog that is deaf, what percent of their offspring will be deaf?
50%
0%
25%
100%

Explanation:

Step1: Determine the genotypes

Let the allele for normal hearing be \(D\) and for deafness be \(d\). The female dog is heterozygous, so her genotype is \(Dd\). The male dog is deaf, so his genotype is \(dd\).

Step2: Set up the Punnett square

	\(D\)	\(d\)
\(d\)	\(Dd\)	\(dd\)

Step3: Calculate the probability

Out of 4 possible offspring genotypes (\(Dd, Dd, dd, dd\)), 2 are \(dd\) (deaf). The probability is \(\frac{2}{4}=\frac{1}{2} = 50\%\)

Answer:

50%