Genetics Help Please!?

Question

1- In rabbits, short hair is due to a dominant allele (S) & long hair to a recessive allele (s). A cross between a short haired- female & a long haired male produces a litter of 1 long haired & 7 short haired offspring.
a- What are the genotypes of the parents?
b-What phenotypic ratio was expected in the offspring generation?
c-How many of the 8 offspring were expected to be long haired?
d-If the female had been homozygous short haired animal,how many of the 8 offspring would have been expected to be long haired?
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Should my punnett square be set up as Ss x ss? I think that's wrong... and I'm confusing myself. = /
I know it's probably a lot simpler then I'm making it seem.

I know it's a lot, but can someone please explain this to me, I would really appreciate it. Thank you! = )

Answer 1

a) The parents must be Ss (female) and ss (male) in order to get both long and short haired offspring.

b) with this cross, you would expect a 1:1 short to long hair ratio of the offspring.
S s
s Ss ss
s Ss ss

c) I imagine you can figure that one out using the above ratio, but it's 4.

d) If she has been homozygous short hair, there'd be no long haired offspring.
S S
s Ss Ss
s Ss Ss

Hope that helps...

-a Genetics TA

Answer 2

You are right in how your Punnet square should be set up. Clearly there is another factor involved and this is a bit of a trick set up. Just have some confidence, and answer the questions from the way you set up your Punnet square, it is correct.