Question

bonus:
a widows peak hairline is dominant (w) to a straight hairline (w). karen and her
brother both have a straight hairline, but her parents and sister all have a
widows peak. complete the punnett square that shows karens family.
dad
w w
phenotype probability (%)
w
ww ww
widows peak hairline: 75%
w
ww ww
straight hairline: 25%

Explanation:

Step1: Determine the parents' genotypes

Since Karen and her brother have a straight hairline (ww), and parents have widow's peak (dominant trait). For parents to have offspring with ww, both parents must carry the recessive allele. So parents' genotypes are Ww (heterozygous).

Step2: Construct the Punnett square

	W	w
w	Ww	ww

Step3: Calculate probabilities

• Widow's peak (WW + Ww + Ww): There are 3 out of 4 combinations ($\frac{3}{4}=0.75 = 75\%$)
• Straight hairline (ww): 1 out of 4 combinations ($\frac{1}{4}=0.25=25\%$)

Answer:

Widow’s Peak Hairline: 75%, Straight Hairline: 25%