Compare and contrast the following terms:

dominant and recessive

Key Concepts

Dominant Alleles

Dominant alleles are variants of a gene that express their traits even when only one copy is present in the genotype. This means that if an individual has at least one dominant allele for a trait, that trait will be observed in the phenotype. For example, in pea plants, the allele for purple flowers is dominant over the allele for white flowers.

Recessive Alleles

Recessive alleles are gene variants that only express their traits when two copies are present in the genotype. If an individual has one dominant and one recessive allele, the dominant trait will mask the effect of the recessive one. Using the pea plant example, white flowers appear only when the plant has two recessive alleles for that trait.

Mendelian Inheritance

Mendelian inheritance refers to the patterns of inheritance first described by Gregor Mendel, which include the principles of dominance and recessiveness. According to these principles, traits are inherited independently and can be predicted using ratios based on the alleles present in the parents. This framework helps explain how dominant and recessive traits are passed on through generations.