Join thousands of students who trust us to help them ace their exams!Watch the first video
Multiple Choice
In a monohybrid cross between two homozygous parents (one dominant and one recessive), what is the expected phenotype of the F1 offspring?
A
All offspring will display the dominant phenotype and be uniform.
B
All offspring will display the recessive phenotype.
C
The offspring will show a 3:1 ratio of dominant to recessive phenotypes.
D
Half of the offspring will display the dominant phenotype, and half will display the recessive phenotype.
Verified step by step guidance
1
Identify the genotypes of the two homozygous parents. One parent is homozygous dominant (e.g., $AA$) and the other is homozygous recessive (e.g., $aa$).
Determine the genotype of the F1 offspring by performing the cross: $AA \times aa$. Each offspring receives one allele from each parent, so all F1 genotypes will be heterozygous ($Aa$).
Recall that in a monohybrid cross, the dominant allele masks the recessive allele in heterozygous individuals, so the phenotype of $Aa$ will be the dominant trait.
Conclude that since all F1 offspring have the genotype $Aa$, they will all display the dominant phenotype and be uniform in appearance.
Understand that this result differs from a typical 3:1 ratio, which appears in the F2 generation after crossing two heterozygous F1 individuals.