3. Attached earlobes (A) are dominant over unattached earlobes (a). Tonguerollin

Question

3. Attached earlobes (A) are dominant over unattached earlobes (a). Tonguerolling (T) is the ability to roll the tongue into a U' shape, and it is dominant over nonroller (t), who cannot do it. What are the phenotypes of these traits for a young woman who is TtAa? She marries a man who is a nonroller and has unattached earlobes, and they have kids. Using a Punnett square or probabability analysis by multiplication, show all the possible genotypes and phenotypes for the kids, and the chances for each one. (4 pts) 4. The woman in question 3 gets a D-I-V-O-R-C-E, and marries a newer model who is TtAa. Using a second Punnett square, show all possible genotypes of their kids. What is the chance that they'll have a tonguerolling kid with unattached earlobes? (4 pts)

Explanation / Answer

Attached earlobes (A) > unattached earlobes (a)
Tongue-rolling (T) > nonroller (t)
ANSWER 3
Woman = TtAa // Woman's gametes = TA, tA, Ta, ta
Man = ttaa // Man's gametes = ta
Possible genotypes = TtAa, ttAa, Ttaa, ttaa
Possbile phenotypes =  Attached earlobes & Tongue-rolling, nonroller & Attached earlobes, Tongue-rolling & unattached earlobes, nonroller & unattached earlobes
Chances = 1/4 or 0.25 for all cases

ANSWER 4
Woman = TtAa // Woman's gametes = TA, tA, Ta, ta
New Man = TtAa // Man's gametes = TA, tA, Ta, ta
Possible genotypes =
// TA // Ta // tA // ta
TA // TTAA // TTAa // TtAA // TtAa
Ta // TTAa // TTaa // TtAa // Ttaa
tA // TtAA // TtAa // ttAA // ttAa
ta // TtAa // Ttaa // ttAa // ttaa
Possbile phenotypes = 9 Attached earlobes & Tongue-rolling, 3 nonroller & Attached earlobes, 3 Tongue-rolling & unattached earlobes, 1 nonroller & unattached earlobes
Chances for tongue-rolling kid with unattached earlobes = 3/16

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