Question 3 of 10

For a certain breed of cat, short tails are dominant [tex]\((T)\)[/tex] and long tails are recessive [tex]\((t)\)[/tex]. The Punnett square below shows a cross between two parents. What is the phenotype ratio for this cross?

\begin{tabular}{|c|c|c|}
\hline & [tex]$t$[/tex] & [tex]$t$[/tex] \\
\hline [tex]$T$[/tex] & [tex]$T t$[/tex] & [tex]$T t$[/tex] \\
\hline [tex]$t$[/tex] & [tex]$t t$[/tex] & [tex]$t t$[/tex] \\
\hline
\end{tabular}

A. 2 long, 2 short
B. 0 long, 4 short
C. 3 long, 1 short
D. 4 long, 0 short



Answer :

To determine the phenotype ratio for this cross, let's analyze the given Punnett square:

[tex]\[ \begin{tabular}{|c|c|c|} \hline & $t$ & $t$ \\ \hline $T$ & $Tt$ & $Tt$ \\ \hline $t$ & $tt$ & $tt$ \\ \hline \end{tabular} \][/tex]

From the Punnett square, we can observe the resulting genotypes for the offspring of these two parents:

1. [tex]\(Tt\)[/tex]
2. [tex]\(Tt\)[/tex]
3. [tex]\(tt\)[/tex]
4. [tex]\(tt\)[/tex]

Next, let's count the occurrences of each genotype:
- [tex]\(Tt\)[/tex]: 2 times
- [tex]\(tt\)[/tex]: 2 times

Now, we need to translate these genotypes into the corresponding phenotypes.

- Genotype [tex]\(Tt\)[/tex] (heterozygous) results in a short tail, as the trait for short tails is dominant.
- Genotype [tex]\(tt\)[/tex] (homozygous recessive) results in a long tail, as the trait for long tails is recessive.

From the counts we determined:
- 2 offspring have the genotype [tex]\(Tt\)[/tex], which corresponds to the short tail phenotype.
- 2 offspring have the genotype [tex]\(tt\)[/tex], which corresponds to the long tail phenotype.

Thus, the phenotype ratio is:
- 2 short tails
- 2 long tails

The correct answer is:
A. 2 long, 2 short