Question

The gene for petal color in a flower has incomplete dominance, so that individuals with two A1 alleles (A1A1) are black, individuals with two A2 alleles (A2A2) are white, and individuals with one of each allele (A1A2) are mottled. In a cross between two black flowers, what is the probability of getting a mottled offspring? (2

Answer 1

Answer:

The probability of getting a mottled offspring is 0%. There is no A2 allele involved in the cross.

Explanation:

Available data:

• The gene for petal color in a flower has incomplete dominance

• Two A1 alleles (A1A1) express black color

• Two A2 alleles (A2A2) express white color

• One of each allele (A1A2) express mottled color

In a cross between two black flowers, there is no allele A2, there are just two alleles A1. So, the cross is:

Parental)    A1A1    x    A1A1

Gametes)  A1   A1       A1   A1

Punnet Square)     A1         A1

                   A1    A1A1     A1A1

                   A1     A1A1     A1A1

F1 Phenotypes: 100% black flowers

F1 Genotype: 100% A1A1

There are 0% of probabilities of getting a mottled offspring.

Answer 2

Answer:

The probability is 0%.

Explanation:

We know that an individual with two A1 alleles (A1A1) are black, so if two black flowers are crossed that means two flowers with A1 (black)alleles, as these flowers do not have any A2 allele to give a mottled flower, the only type of flower that will come out from this cross is a black one.

We can see this with a Punnett square.

   ║A1        ║     A1    

A1║  A1A1  ║    A1A1    

A1║ A1A1   ║   A1A1