Question

An F1 individual resulting from a cross between a homozygous dominant parent and a homozygous recessive parent is always:

a) Homozygous dominant
b) Homozygous recessive
c) Heterozygous
d) Hemizygous

Answer 1

An F1 individual from a cross between a homozygous dominant and homozygous recessive parent is always heterozygous. A recessive trait is only observed in homozygous individuals for that trait, whereas a heterozygous individual will display the dominant trait.

Step-by-step explanation:

An F1 individual resulting from a cross between a homozygous dominant parent and a homozygous recessive parent is always c) Heterozygous. This is because the offspring will inherit one dominant and one recessive allele for the trait in question. Therefore, the genotype of the F1 progeny will be Aa, where 'A' represents the dominant allele and 'a' represents the recessive allele.

A recessive trait will be observed in individuals that are c) homozygous for that trait. This means the individual must have two copies of the recessive allele (aa) to exhibit the recessive phenotype. When these heterozygous F1 individuals are self-crossed, the resulting F2 generation will show a 3:1 ratio of dominant to recessive phenotypes, because the dominant trait masks the presence of the recessive allele in heterozygous individuals (Aa).