Question

If a plant has a genotype of Aa, we would assume which is true?

1. The a allele is the wild‑type allele for this plant species.
2. The plant has round seeds.
3. This plant had to have one parent of AA genotype and one parent of aa genotype.
4. The A allele is dominant to the a allele.
5. The a allele is dominant to the A allele.

Answer 1

The genotype Aa suggests that the A allele is dominant to the a allele. Without additional information, we cannot infer the trait's expression, the parental genotypes, or which allele is the wild-type. option 4.

Step-by-step explanation:

If a plant has a genotype of Aa, it would imply that the A allele is dominant to the a allele. This is because dominant alleles are expressed in the phenotype even when only one copy is present, as is the case in a heterozygous individual with an Aa genotype. The dominance relationship between alleles is standard practice in genetics notation, where the dominant allele is typically represented by a capital letter and the recessive by a lowercase letter, as seen in the work of Gregor Mendel with pea plants. As for other assumptions, without additional context, we cannot determine the phenotypic outcome such as seed shape, nor the genotypes of the parents, since a heterozygous plant (Aa) could come from various combinations of parental genotypes such as AA x aa, Aa x Aa, Aa x AA, or Aa x aa. The statement that the a allele is the wild-type allele cannot be inferred without specific information about the alleles' prevalence and function in the natural population of the species in question.

Answer 2

4. The A allele is dominant to the a allele.

Step-by-step explanation:

In genetics, the dominant allele which is expressed when present in single or two copies is always written with an upper case letter. The corresponding allele whose expression is prevented in the presence of the dominant allele is written in the "lower case letter". This is called recessive allele. In the given genotype, one copy of "A" and one copy of "a" is present. This means that the allele written with upper case letter "A" is dominant over the allele "a". Nothing can be said about the genetic trait regulated by these two alleles of a gene.