Solved Sample Paper 2 — Question 18

A dominant allele expresses itself while the recessive allele is masked in heterozygous condition. For example, when a plant with round (RR) seeds is crossed with a plant with wrinkled (rr) seeds, all F₁ plants are with round seeds. Here, the genes are in heterozygous condition i.e., Rr. Allele 'r' is present but is not expressed as its effect is masked by allele 'R'. Therefore, we can say that a trait may be inherited but may not be expressed.