Okay, I totally don't get this. It says: In peas, the alele for green pods(G) is dominant over the alele for yellow pods(g). Below shows the phenotypes of offspring produced from a cross of two plants with green pods.
Green pods - 27 offspring
yellow pods - 9 offspring
What are the two genotypes of the parents? How do you know?
If both the plants have green pods, but some of the offspring came out with yellow, but most green, one must be GG and the other Gg. Ha! I answered my own question!
To determine the genotypes of the parents, we need to understand Mendelian inheritance and use the given information about the phenotypes of the offspring.
In this case, we have two phenotypes: green pods and yellow pods. The alele for green pods (G) is dominant over the alele for yellow pods (g).
Let's assign the genotypes of the parents as follows:
- Parent 1: Genotype = GG or Gg (has at least one dominant G alele)
- Parent 2: Genotype = gg (has two recessive g aleles)
Now, let's analyze the offspring data provided:
- 27 offspring have green pods
- 9 offspring have yellow pods
Since green pods are the dominant phenotype, we can conclude that all the offspring with green pods have at least one dominant G alele from one of the parents. This means that both the homozygous dominant (GG) and heterozygous (Gg) genotypes can result in the green pod phenotype.
On the other hand, the offspring with yellow pods must have received two recessive g aleles because yellow pods are the recessive phenotype. This implies that both the homozygous recessive (gg) genotype is necessary for the yellow pod phenotype.
Based on this information, we can deduce that Parent 1 (either GG or Gg) must have contributed a dominant G alele, while Parent 2 must have contributed a recessive g alele (gg). The exact genotypes of the parents cannot be determined with certainty without further information or additional offspring data.