Question

parents that are heterozygous for having freckles (dominant) are crossed. which correctly describes their offspring?
twenty - five percent have freckles.
twenty - five percent are f1.
seventy - five percent have freckles.
seventy - five percent are f1.

Explanation:

Step1: Determine the genotypes of the parents

Let \(F\) represent the dominant allele (for freckles) and \(f\) represent the recessive allele (no freckles). The parents are heterozygous, so their genotypes are \(Ff\).

Step2: Set up the Punnett square

	\(F\)	\(f\)
\(f\)	\(Ff\)	\(ff\)

Step3: Analyze the offspring genotypes

The genotypes of the offspring are \(FF:Ff:ff = 1:2:1\). The \(FF\) and \(Ff\) genotypes result in the freckled phenotype (since \(F\) is dominant).

Step4: Calculate the percentage of freckled offspring

The proportion of \(FF\) is \(\frac{1}{4}\) and the proportion of \(Ff\) is \(\frac{2}{4}\). The total proportion of freckled offspring (\(FF + Ff\)) is \(\frac{1 + 2}{4}=\frac{3}{4}=75\%\)

Answer:

Seventy - five percent have freckles.