Question

Sometimes there can be more than one desirable gene. You are going to give two plants of your favorite tomato variety to a friend, and you want both of them to have the desirable allele at each of two genes. At gene one, you know the parents are both heterozygotes; at gene two, the mother is heterozygous and the father is homozygous for the desirable allele. What is the probability of any given seed being heterozygous for both genes?

Answer 1

1/4 or 25%

Step-by-step explanation:

This question illustrates a cross involving two genes coding for two desirable traits in a tomato plant. Let's assume that the desirable traits are coded for by the dominant alleles B and C.

According to the question, the female parent is heterozygous for both genes B and C i.e. will have a genotype, BbCc while the father is heterozygous for Gene B and homozygous for the desirable trait in gene C I.e. will have a genotype, BbCC

N.B: Dominant alleles B and C are responsible for the desirable traits.

In a cross between parents: BbCc and BbCC, each parent will produce gametes according to Mendel's law of segregation. The possible gamete combinations are:

BbCc - BC, Bc, bC and bc

BbCC - BC, BC, bC and bC

Using these gametes in a punnet square (see attached image), 16 possible seed offsprings will be produced. However, out of the 16 possible offsprings, 4 of them will likely be heterozygous for both genes i.e. possess a genotype, BbCC.

Hence, 4/16 = 1/4 is the probability of a given seed to be heterozygous for both genes.

Answer 2

The odds are 50% of both the heterozygous (mother) and the homozygous (father)

Expla

This happens thanks to Mendel's theory of segregation, the father of genetics, where he mentions that there is always a 50% chance of inheriting certain traits from either the father or the mother, the only thing that could influence which characteristics is more problabe its appearance in the new tomato plants, it will be a gene that is stronger with respect to another, what we call the predominant gene, which increases the chances of appearing in new generations, however there is also the possibility of inherit genes from past generations.