In guinea pigs, rough coats (with lots of swirly cowlicks) are dominant over smooth coats. If a male homozygous dominant guinea pig is crossed with a female heterozygous guinea pig, what are the possible genotypes and phenotypes of the offspring? Complete the Punnett square and the percentages of rough and smooth coated offspring.

Question

***Please follow all Punnett square rules to complete this question. (Letters and numbers, only)

Please use the following: Rough = R and Smooth = r

Answer 1

The possible genotypes of the offspring can be determined by the following Punnett square:

R R x R r
--------------
R R | R R
R r | R r

The possible genotypes of the offspring are: RR and Rr.

The possible phenotypes of the offspring are: Rough and smooth.

Since rough coats (R) are dominant over smooth coats (r), all the offspring with the genotype RR will have a rough coat phenotype.

The offspring with the genotype Rr will also have a rough coat phenotype because rough is dominant over smooth.

Therefore, the percentages of rough and smooth coated offspring are as follows:

- Rough (RR): 50%
- Rough (Rr): 50%

There will be no smooth coated offspring in this particular cross.