Question

Based on Mendel's original work, what can be inferred about the genotypes of the parents of the field of sunflowers with 774 tall (T) plants and 226 short (t) plants?

a) Both parents were heterozygous (Tt)
b) Both parents were homozygous dominant (TT)
c) One parent was homozygous dominant (TT) and the other homozygous recessive (tt)
d) One parent was heterozygous (Tt) and the other homozygous recessive (tt)

Answer 1

The parents of the sunflower plants are most likely both heterozygous (Tt) as their offspring follow Mendel's expected 3:1 phenotypic ratio of dominant to recessive traits.

Step-by-step explanation:

The genotypes of the parents in a field of sunflowers with 774 tall (T) plants and 226 short (t) plants can be inferred as both being heterozygous (Tt). This inference is based on the phenotypic ratio observed in the offspring, which is close to the expected 3:1 dominant to recessive ratio, a result of two heterozygous individuals mating according to Mendelian genetics principles.

When two heterozygous (Tt) parents are crossed, four possible combinations can result in their offspring: TT, Tt, tT, and tt. According to Mendel’s principles, the probability is that 25% will be homozygous recessive (tt) and therefore short, and 75% will have at least one dominant allele (T), resulting in a tall phenotype. This coincides with the observed numbers of tall and short plants (774 tall to 226 short), making option a) the most likely scenario for the genotypes of the parents.