In cats, having a short tail is recessive to having a long tail. If a mother cat is heterozygous for this trait and a father cat is homozygous dominant for having a long tail, what will most likely be true about their offspring?

A. All will have long tails.
B. All will have short tails.
C. About [tex]\frac{3}{4}[/tex] will have short tails.
D. About [tex]\frac{1}{2}[/tex] will have long tails.



Answer :

To determine the likelihood of the offspring's traits in cats where having a short tail is recessive to having a long tail, we need to analyze the genetic information from the parents.

Given:
- The mother cat is heterozygous for this trait, which means she has one dominant allele and one recessive allele. Her genotype is [tex]\(Ll\)[/tex].
- The father cat is homozygous dominant, meaning he has two dominant alleles. His genotype is [tex]\(LL\)[/tex].

Let's consider the possible offspring genotypes based on these parental genotypes:

1. The mother can pass on either the [tex]\(L\)[/tex] (long tail) allele or the [tex]\(l\)[/tex] (short tail) allele.
2. The father can only pass on the [tex]\(L\)[/tex] (long tail) allele, as his genotype is [tex]\(LL\)[/tex].

We can create a Punnett square to visualize the possible combinations of alleles from the parents:

[tex]\[ \begin{array}{c|cc} & L & L \\ \hline L & LL & LL \\ l & Ll & Ll \\ \end{array} \][/tex]

From this Punnett square, the potential genotypes of the offspring are:

- [tex]\(LL\)[/tex] (long tail): from the combination of [tex]\(L\)[/tex] from the mother and [tex]\(L\)[/tex] from the father.
- [tex]\(Ll\)[/tex] (long tail): from the combination of [tex]\(l\)[/tex] from the mother and [tex]\(L\)[/tex] from the father.

Now we interpret these combinations:
- [tex]\(LL\)[/tex] and [tex]\(Ll\)[/tex] both result in the phenotype of a long tail because the allele for a long tail ([tex]\(L\)[/tex]) is dominant over the allele for a short tail ([tex]\(l\)[/tex]).

Since both possible genotypes ([tex]\(LL\)[/tex] and [tex]\(Ll\)[/tex]) produce long tails, we conclude that all of their offspring will have long tails.

Therefore, the correct statement is:
- All will have long tails.

The resulting probability of offspring having long tails is 1.0 (or 100%), and the probability of having short tails is 0.0 (or 0%).