Question

2. A widow's peak (W) is dominant to a straight hairline (w), and unattached earlobes (E) is dominant to attached earlobes (e). Two parents, each with the genotype WwEe, have kids. a. What proportion of their offspring will have a widow's peak and unattached earlobes? b. What proportion will have unattached earlobes but have either a widow's peak or a straight hairline? 3. A woman with normal color vision, whose mother was colorblind, has children with a man with normal color vision. a. What is the genotype of the woman? b. What is the genotype of the woman's father? c. What is the probability the woman and man's sons will be colorblind? 4. Brown eyes are dominant over blue (this is not a sex-linked trait). A blue-eyed colorblind woman marries a man who is not colorblind and is heterozygous for brown eye color. What is the probability they will have a blue-eyed colorblind child?

Answer 1

2. Dominant allele = W = Widow's peak
Recessive allele = w = Straight hairline
Dominant allele = E = Unattached earlobes
Recessive allele = e = Attached earlobes

Parent 1 = EeWw
Parent 2 = EeWw

Parental cross: EeWw X EeWw
Progeny:
9/16 = E_W_ = Widow's peak and unattached earlobes
3/16 = E_ww = Normal hairline and unattached earlobes
3/16 = eeW_ = Widow's peak and attached earlobes
1/16 = eeww = Normal hairline and attached earlobes

Probability for the progeny to have the widow's peak and unattached earlobes = 9/16
Probability for the progeny to have the widow's peak/normal hairline and unattached earlobes = 12/16 = 3/4

3. Dominant allele = XC = Normal vision
Recessive allele = Xc = Colorblindness

Woman = XCXc
Man = XCY

Parental cross: XCXc X XCY
Progeny:
XCXC = Unaffected female
XCY = Unaffected male
XCXc = Unaffected carrier female
XcY = Affected male
The probability for an affected male = 1/2
= 25%

4. Dominant allele = B = Brown eyes
Recessive allele = b = Blue eyes

Woman = bb XcXc
Man = Bb XCY

Parental cross: bb XcXc X Bb XCY
Progeny:
The probability for a child to be blue-eyed and colorblind = 1/2 X 1/2
= 1/4
= 25%

Pls provide positive rating