Question

in certain breeds of cats, kinked tails are due to a recessive allele (t) of a particular gene, and a normal long tail is due to its dominant allele (t). what percentage of the offspring of a normal heterozygous cat and a kinked - tail cat would be expected to have a normal long tail?

Explanation:

Step1: Determine the genotypes of the parents

The normal heterozygous cat has the genotype \(Tt\) (since it has a normal long tail which is dominant and is heterozygous). The kinked - tail cat has the genotype \(tt\) (because kinked tail is recessive and for a recessive trait to be expressed, the genotype must be homozygous recessive).

Step2: Set up the Punnett square

Gametes of \(Tt\)	Gametes of \(tt\)
\(t\)	\(t\)

The possible genotypes of the offspring are obtained by combining the gametes:

• \(T\times t=Tt\)
• \(T\times t=Tt\)
• \(t\times t = tt\)
• \(t\times t=tt\)

The genotypes of the offspring are \(Tt\) and \(tt\) in a \(1:1\) ratio.

Step3: Determine the phenotype based on genotype

Since \(T\) (normal long tail) is dominant over \(t\) (kinked tail), the \(Tt\) genotype will result in a normal long - tail phenotype and \(tt\) will result in a kinked - tail phenotype.
The proportion of \(Tt\) (normal long tail) offspring is \(\frac{1}{2}\) or \(50\%\)

Answer:

50%