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



Answer :

GinnyAnswer
To determine the phenotype ratio for the given cross, we need to first identify the possible genotypes and then determine the corresponding phenotypes.

The Punnett square is structured as follows:

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

Let's break down the genotypes and their corresponding phenotypes:
- TT: This genotype is homozygous dominant. Cats with this genotype will have short tails.
- Tt: This genotype is heterozygous. Cats with this genotype will also have short tails since short tails are dominant.
- tt: This genotype is homozygous recessive. Cats with this genotype will have long tails since long tails are recessive.

Now, let's count the number of each genotype from the Punnett square:
- TT: There is 1 square with this genotype.
- Tt: There are 2 squares with this genotype.
- tt: There is 1 square with this genotype.

Next, let's count the number of each phenotype:
- Short tail (dominant phenotype):
- 1 (TT) + 2 (Tt) = 3
- Long tail (recessive phenotype):
- 1 (tt) = 1

Therefore, the phenotype ratio for this cross is 3 short tails to 1 long tail.

So, the correct choice is:
D. 3 short, 1 long

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