Dictionary > Overdominance

Overdominance

Definition
noun
(genetics) A type of dominance characterized by a phenotype that is more pronounced in a heterozygote relative to that of the counterpart homozygote
Supplement
In genetics, dominance refers to a property of a gene (or allele) in relation to other genes or alleles wherein a gene (or allele) shows dominance as it suppresses the expression, or dominates the effects, of the recessive gene (or allele). According to the law of dominance proposed by Gregor Mendel, in a pair of genes or alleles in heterozygous condition, the allele that is expressed is described as dominant. In contrast, the allele that is not expressed is recessive. However, there are instances wherein the pattern of phenotypes does not follow the laws in inheritance proposed by Gregor Mendel. One of them is overdominance.
In overdominance, the heterozygote produced by two homozygote parents shows a phenotype that is more pronounced than that of the parents. Overdominance may also mean that the heterozygote has a higher fitness relative to the counterpart homozygotes. An example of this is a heterozygote for sickle cell anemia. The heterozygote individual would have less physiological effects of the condition and have partial resistance to malaria as opposed to the homozygotes suffering more from the deleterious effects of sickle cell anemia or have no similar protective resistance against malaria.
See also:

Related term(s):

Related form(s):

  • overdominant (adjective, of, relating to, or characterized by overdominance)

You will also like...

Independent Assortment and Crossing Over
Independent Assortment and Crossing Over

This tutorial describes the independent assortment of chromosomes and crossing over as important events in meiosis. Read..

Photosynthesis and respiration
Plant Metabolism

Plants are responsible for incredible feats of molecular transformation. Plant processes, such as photosynthesis, photop..

temperature - abiotic factor
Abiotic and Biotic Factors

This tutorial deals with the abiotic factors of the freshwater environment that determine what sort of life would be sui..

Lotic community of algal species
Lotic Communities & Algae

Lotic communities have conditions that are rather harsh for typical plants. Thus, the diversity of plant species in loti..

Gibberellins and Gibberellic Acid
Gibberellins and Gibberellic Acid

This tutorial describes the role of gibberellin family in plants. Find out the effects of gibberellin on plant growth an..

Human perception in action
Human Perception – Neurology

This tutorial investigates perception as two people can interpret the same thing differently. Know more about human perc..

Related Articles...

No related articles found

See all Related Topics