Question

Using the product rule of probability, calculate the odds of getting an individual that receives the bb genotype and therefore shows the recessive trait, white flowers. A) 1/4 X 1/4 = 1/16 B) 1/2 X 1/2 = 1/4 C) 1/4 + 1/4 = 1/2 D) 3 X 1/4 = 3/4; 1 - 3/4 = 1/4

Answer 1

Answer:

B) 1/2 X 1/2 = 1/4

Explanation:

It happens when both the parents are heterozygous for the trait. The cross related to this result is shown as under:

                          Father           Mother

                             Bb       x        Bb

                             /   \                 /   \

Gametes:           B      b            B      b

                          |        |              |       |

Probability:      1/2     1/2          1/2    1/2

The probability of formation of 'b' gamete from father is 1/2 because there are only two gametes 'B' and 'b' and out of these two one will be assorted as 'B' and another one as 'b' and from mother also the probability of formation of 'b' gamete is 1/2.

Now the assortment of gametes with each other is an independent event i.e. any gamete from father can fuse with any gamete of mother so the overall probability of formation of 'bb' genotype will be 1/2 x 1/2 = 1/4.