Question

A female wild type head top mates with a flat head top and produces all wild type head tops. The result of the following cross indicates that genotypically the offspring _____.

A. Are all homozygous recessive
B. Are all homozygous dominant
C. Are all heterozygous
D. Cannot be determined

Answer 1

The offspring of a cross between a homozygous wild type head top and a flat head top are all heterozygous, carrying both a dominant wild type allele and a recessive flat head allele.

Step-by-step explanation:

When a female wild type head top mates with a flat head top and all offspring are wild type head tops, it indicates the offspring are all heterozygous. This result stems from a cross between a homozygous dominant (wild type) parent and a homozygous recessive (flat head top) parent, where the dominant trait, wild type head top, is expressed in all F1 offspring. The genotypes of the F1 offspring would be one dominant allele for the wild type characteristic and one recessive allele for the flat head, which is not expressed in the phenotype due to the dominant nature of the wild type allele. Therefore, all F1 offspring from this cross are heterozygous.