Question

A plant has dominant and recessive traits for flower color. The dominant color is amethyst (a), and the recessive trait is white (a). Which punnett square correctly shows two homozygous parents producing heterogeneous offspring?

1) a a a aa aa a aa aa
2) a a a aa aa a aa aa
3) a a a aa aa a aa aa
4) a a a aa aa a aa aa
5) a a a aa aa a aa aa

Answer 1

The correct Punnett square for homozygous parents producing heterozygous offspring would show one parent with genotype 'AA' and the other with 'aa', resulting in all offspring having the genotype 'Aa'.

Step-by-step explanation:

To answer the question about homozygous parents producing heterozygous offspring, we first need to understand the genetic notation for homozygous dominant, heterozygous, and homozygous recessive traits. In this example, the dominant flower color is amethyst, which we will represent as 'A', and the recessive color is white, which we will represent as 'a'. A homozygous dominant organism would have the genotype 'AA', and a homozygous recessive organism would have the genotype 'aa'. For two homozygous parents to produce heterozygous offspring ('Aa'), one parent must be homozygous dominant ('AA') and the other must be homozygous recessive ('aa'). Using a Punnett square, you would put 'A' from the homozygous dominant parent across the top and 'a' from the homozygous recessive parent down the side to show the potential combinations in their offspring.

The correct Punnett square for this cross would be:

A A
a Aa Aa
a Aa Aa

All the offspring are heterozygous with one dominant allele and one recessive allele, resulting in the genotype 'Aa'.