In a plant in which fuzzy leaves (F) are dominant over smooth leaves (f), which of the following crosses will produce only offspring with smooth leaves?
A.
FF x FF
B.
Ff x Ff
C.
ff x ff
D.
Ff x ff.
The correct answer is:
C. ff x ff
Explanation:
In genetics, the letter F represents the dominant allele for fuzzy leaves, and f represents the recessive allele for smooth leaves. To produce only offspring with smooth leaves, both parents must carry only the recessive allele, f.
Here’s why:
- FF x FF: All offspring will have the genotype
FF, resulting in all fuzzy leaves becauseFis dominant. - Ff x Ff: This cross will produce a mix of genotypes (
FF,Ff, andff), so the offspring will include both fuzzy and smooth leaves. - ff x ff: Both parents are homozygous recessive, so all offspring will be
ffand will have smooth leaves. - Ff x ff: This cross will produce both
Ff(fuzzy) andff(smooth) offspring.
Therefore, the cross that produces only offspring with smooth leaves is ff x ff, as both parents are homozygous recessive and can only pass on the recessive allele f.