Multiple Alleles - Research Article from Macmillan Science Library: Genetics

This encyclopedia article consists of approximately 3 pages of information about Multiple Alleles.
This section contains 610 words
(approx. 3 pages at 300 words per page)
Buy the Multiple Alleles Encyclopedia Article

Multiple Alleles

Alleles are alternative forms of a gene, and they are responsible for differences in phenotypic expression of a given trait (e.g., brown eyes versus green eyes). A gene for which at least two alleles exist is said to be polymorphic. Instances in which a particular gene may exist in three or more allelic forms are known as multiple allele conditions. It is important to note that while multiple alleles occur and are maintained within a population, any individual possesses only two such alleles (at equivalent loci on homologous chromosomes).

Examples of Multiple Alleles

Two human examples of multiple-allele genes are the gene of the ABO blood group system, and the human-leukocyte-associated antigen (HLA) genes.

The ABO system in humans is controlled by three alleles, usually referred to as IA, IB, and IO (the "I" stands for isohaemagglutinin). IA and...

(read more)

This section contains 610 words
(approx. 3 pages at 300 words per page)
Buy the Multiple Alleles Encyclopedia Article
Copyrights
Macmillan
Multiple Alleles from Macmillan. Copyright © 2001-2006 by Macmillan Reference USA, an imprint of the Gale Group. All rights reserved.
Follow Us on Facebook