Answered

For a type of cat, short whiskers are dominant [tex]$(S)$[/tex] and long whiskers are recessive [tex]$(s)$[/tex]. The Punnett square below shows a cross between two cats. What is the phenotype ratio for this cross?

\begin{tabular}{|c|c|c|}
\hline & [tex]$S$[/tex] & [tex]$s$[/tex] \\
\hline [tex]$s$[/tex] & [tex]$Ss$[/tex] & [tex]$ss$[/tex] \\
\hline [tex]$s$[/tex] & [tex]$Ss$[/tex] & [tex]$ss$[/tex] \\
\hline
\end{tabular}

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



Answer :

Let's analyze the given Punnett square to determine the phenotype ratio from the cross between two cats.

The Punnett square provided is as follows:
\begin{tabular}{|c|c|c|}
\hline & [tex]$S$[/tex] & [tex]$s$[/tex] \\
\hline [tex]$s$[/tex] & [tex]$S s$[/tex] & [tex]$s s$[/tex] \\
\hline [tex]$s$[/tex] & [tex]$S s$[/tex] & [tex]$s s$[/tex] \\
\hline
\end{tabular}

From this Punnett square, we have the following:
- The top row and the left column represent the alleles from each parent cat.
- Inside the Punnett square, each cell represents the possible allele combinations for the offspring.

Here are the combinations:
1. Top left cell: [tex]\( S s \)[/tex] (short whiskers, as [tex]\(S\)[/tex] is dominant)
2. Top right cell: [tex]\( s s \)[/tex] (long whiskers, as both alleles are recessive)
3. Bottom left cell: [tex]\( S s \)[/tex] (short whiskers, as [tex]\(S\)[/tex] is dominant)
4. Bottom right cell: [tex]\( s s \)[/tex] (long whiskers, as both alleles are recessive)

Now, let's count the phenotypes:
- Short whiskers ([tex]\( S s \)[/tex]): 2 occurrences (top left and bottom left cells).
- Long whiskers ([tex]\( s s \)[/tex]): 2 occurrences (top right and bottom right cells).

Based on these counts, the phenotype ratio for short whiskers to long whiskers is:
- 2 short whiskers : 2 long whiskers

So the correct phenotype ratio provided in the options is:
C. 2 short, 2 long.