The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Genetic variance is the observable diversity of a trait in a population which can be attributed to genetic heterogeneity. Genes can often exist in several different forms or alleles. Some of these alleles produce the same effect as others, but at certain times there are alleles present in a population which have an observable effect on the pheno type of the organism.
Genetic variance is a measure of the level of dissimilarity between alleles within a given population. Some characteristics show no genetic variance. These are ones that are usually highly conserved due to their importance. One example of such a characteristic would be the hemoglobin molecule responsible for the transport of oxygen around the body in humans. Any alteration in the geno type, and hence the pheno type, of this molecule would be fatal. Other characteristics can show a wide genetic variance, such as eye and hair color. These characteristics are less important, hence a greater variability is seen within the population.
Genetic variance is a measure within a population. Consequently, the genetic variance present within a species may be greater than encountered in any breeding population. This would be due to barriers halting the intermixing of genes between all the populations making up a specific species.