Answer:
(a) AABBCC × aabbcc->AaBbCc → 1
(b) AABbCc × AaBbCc->AAbbCC → 1/32
(c) AaBbCc × AaBbCc->AaBbCc → 1/8
(d) aaBbCC × AABbcc->AaBbCc → 1/2
Explanation:
In such cases we calculate the probability of each allelic pair separately.
(a) AABBCC × aabbcc -> AaBbCc
Aa Aa Aa Aa Bb Bb Bb Bb Cc Cc Cc Cc
↓ ↓ ↓
4/4 = 1 4/4 = 1 4/4 = 1
In case of gene A, out of the 4 probable allelic combinations, 4 will be Aa so the probability is 4/4 = 1.
In case of gene B, out of the 4 probable allelic combinations, 4 will be Bb so the probability is 4/4 = 1.
In case of gene C, out of the 4 probable allelic combinations, 4 will be Cc so the probability is 4/4 = 1.
So, the total probability of getting AaBbCc = 1 x 1 x 1 = 1.
(b) AABbCc × AaBbCc -> AA bb CC
AA AA Aa Aa BB Bb Bb bb CC Cc Cc cc
↓ ↓ ↓
2/4 1/4 1/4
In case of gene A, out of the 4 probable allelic combinations, 2 will be AA so the probability is 2/4.
In case of gene B, out of the 4 probable allelic combinations, 1 will be bb so the probability is 1/4.
In case of gene C, out of the 4 probable allelic combinations, 1 will be CC so the probability is 1/4.
So, the total probability of getting AA bb CC = 2/4 x 1/4 x 1/4 = 1/32.
(c) AaBbCc × AaBbCc -> AaBbCc
AA Aa Aa aa BB Bb Bb bb CC Cc Cc cc
↓ ↓ ↓
2/4 2/4 2/4
In case of gene A, out of the 4 probable allelic combinations, 2 will be Aa so the probability is 2/4.
In case of gene B, out of the 4 probable allelic combinations, 2 will be Bb so the probability is 2/4.
In case of gene C, out of the 4 probable allelic combinations, 2 will be Cc so the probability is 2/4.
So, the total probability of getting AaBbCc = 2/4 x 2/4 x 2/4 = 1/8.
(d) aaBbCC × AABbcc->AaBbCc
Aa Aa Aa Aa BB Bb Bb bb Cc Cc Cc Cc
↓ ↓ ↓
4/4 = 1 2/4 4/4 = 1
In case of gene A, out of the 4 probable allelic combinations, 4 will be Aa so the probability is 4/4 = 1.
In case of gene B, out of the 4 probable allelic combinations, 2 will be Bb so the probability is 2/4.
In case of gene C, out of the 4 probable allelic combinations, 4 will be Cc so the probability is 4/4 = 1.
So, the total probability of getting AaBbCc = 1 x 2/4 x 1 = 1/2.
