Law of dominance

Definition

The law of dominance states that in a heterozygote, one allele will mask the expression of another allele. This dominant allele will be expressed in the phenotype, while the recessive allele's effect is not observed.

5 Must Know Facts For Your Next Test

1. The law of dominance was first formulated by Gregor Mendel based on his experiments with pea plants.
2. In a heterozygous individual, only the dominant trait is observed in the phenotype.
3. The recessive trait can reappear in subsequent generations if two recessive alleles are inherited.
4. Dominance does not imply superiority or increased fitness; it merely describes which allele is expressed.
5. The law of dominance applies to traits governed by single genes with two alleles where one is dominant and one is recessive.

Review Questions

• What happens to the recessive allele in a heterozygous organism according to the law of dominance?
• Who first formulated the law of dominance and through what kind of experiments?
• Can a recessive trait appear in future generations if so, how?

Related terms

Homozygous: An organism with two identical alleles for a particular gene.

Heterozygous: An organism with two different alleles for a particular gene.

Phenotype: The observable characteristics or traits of an organism resulting from the interaction of its genotype with the environment.