Question

Two short-haired cats mate and produce six short- haired and two long-haired kittens. What does this information suggest about how hair length is inherited?

Answer 1

In the progeny, six kittens were short haired and two were long haired. The ratio of short to long haired kittens is 3:1 which is a classic monohybrid cross ratio. Here, short hair is inherited dominantly and long hair is inherited recessively. Both the parents are heterozygous for short hair trait (Ss). Cross between them:

Ss X Ss :

S s

S SS Ss

s Ss ss

Genotypically: 1 : 2 : 1

SS Ss ss

Phenotypically: 3 : 1 = 6 short and 2 long haired kittens

short hair long hair

Hence short hair is dominant over long hair in these cats.