Question

Part A, In humans, pointed eyebrows are dominant to smooth eyebrows and widow’s peak is dominant to continuous hairline. What phenotypic results would you expect in the offspring from a cross between an individual heterozygous for both genes and an individual homozygous dominant for both genes? Show work. Doesn't matter what letter is used, just clarify

Part B. Cystic fibrosis is an autosomal recessive disorder and you should consider it exceedingly rare. A man and woman are planning on having a child. Each of them has a parent who is a carrier. It is not known if either the male or the female themselves are carriers. If the male and female have one child, what is the probability that they will have a son with cystic fibrosis? Show work. Doesn't matter what letter is used, just clarify

Answer 1

Part A.

P-pointed eyebrow p-smooth eyebrow

W- widow's peak w-continuous hairline

Individual 1 PpWw

Individual 2 PPWW

PpWw X PPWW

	PW	Pw	pW	pw
PW	PPWW Pointed eyebrow Widow peak	PPWw Pointed eyebrow Widow peak	PpWW Pointed eyebrow Widow peak	PpWw Pointed eyebrow Widow peak

Thus,100% offsprings with pointed eyebrows and with widow's peak.

Part B.

In this case the genotype of male and female could be CC or Cc. There are chances that they might have inherited one defective recessive allele from their parents.

Case 1. One parent CC and another CC

100% offsprings CC means normal

Case 2. One parent CC and another Cc or vice versa

50% CC 50% Cc (Carrier All normal)

Case 3. Both parents Cc

Offsprings- 25% CC- normal

50% Cc Carrier but normal

25% affected cc

So,75% normal and 25% affected