Draw a Punnett square of an Ss x ss cross. The Sallele codes for long stems in pea plants and the s allele codes for short stems. If S is dominant to s, what percentage of the offspring would you expect to have each phenotype?

Question

Draw a Punnett square of an Ss x ss cross. The Sallele codes for long stems in pea plants and the s allele codes for short stems. If S is dominant to s, what percentage of the offspring would you expect to have each phenotype?

• 50% Long Stem/50% Short Stem
- 75% Long Stem/25% Short Stem
• 100% Long Stem/0% Short Stem
• 25% Long Stem/75% Short Stem

Answer 1

Here is the Punnett square for an Ss x ss cross:

s s
S Ss Ss

From this Punnett square, we can see that 50% of the offspring would have long stems (Ss genotype) and 50% would have short stems (ss genotype).

So, the expected phenotype percentages would be:
• 50% Long Stem/50% Short Stem for this cross.