A tall pea plant results from a dominant tall allele while the short phenotype results from two recessive alleles. What is the frequency of short offspring (pp) when a tall pea plant with one tall allele (Pp) is cross-pollinated with a short pea plant (pp)?(1 point)

Question

Responses

0.75
0.75

0.25
0.25

1.0
1.0

0.5

Answer 1

To determine the frequency of short offspring (pp) when crossing a tall pea plant with genotype Pp (heterozygous) and a short pea plant with genotype pp (homozygous recessive), we can set up a Punnett square.

• The Pp parent can contribute either a P (tall) or a p (short) allele.
• The pp parent can only contribute a p (short) allele.

Here’s the Punnett square for the cross:

      P        |        p
----------------|----------------
   p   |     Pp     |      pp  
----------------|----------------
   p   |     Pp     |      pp  

From the Punnett square, we see the following genotypes for the offspring:

• 2 Pp (tall)
• 2 pp (short)

Out of a total of 4 offspring:

• 2 are short (pp).

Thus, the frequency of short offspring (pp) is:

\[ \text{Frequency of } pp = \frac{2 \text{ (pp)}}{4 \text{ (total offspring)}} = 0.5 \]

Therefore, the answer is 0.5.