Definition of Dominant Gene

A dominant gene refers to a specific gene variant that is more likely to be expressed in an organism’s phenotype over another alternative gene variant, known as a recessive gene. Dominant genes are able to exert their influence even when present in only one copy within a pair of corresponding chromosomes.

Gene variants: Dominant and Recessive

Each gene can have different forms, known as gene variants or alleles. When an organism has two different alleles for a specific gene, one is usually dominant while the other is recessive. Dominant gene variants are more influential in determining the physical or physiological traits of an organism.

Expression in the Phenotype

Dominant genes are capable of producing a certain trait or characteristic when present in the chromosome pair. Even if a recessive gene allele is also present, the dominant allele takes precedence and determines the observable trait in the organism. The expression of dominant genes can override the presence of a recessive allele.

Significance in Human Genetics

Dominant genes are significant in human genetics as they can determine the presence of various traits or conditions. Some dominant genetic disorders, such as Huntington’s disease, result from the presence of a dominant gene. These disorders may appear in an individual even if only one affected parent passes down the dominant gene variant.