Allele Member Function
Date: Winter 2011-2012
Does a single allele function at all if it is not paired off with a corresponding allele at the gene locus?
We oftentimes inherit two different forms of a gene from each of our parents - the different versions of the gene are known as "alleles". In some instances only one of the inherited alleles is functional. In many (if not most) circumstances having only one functional copy of a gene is sufficient to avoid disease. Diseases averted by having only one functional allele are known as "recessive" as these diseases are avoided by inheriting a single functional "dominant" version of the gene. Examples of recessive diseases include cystic fibrosis and sickle-cell disease.
Genes contain information which cells within the body use to construct proteins. While having only one functional gene does usually reduce the amount of a corresponding protein made by cells, this reduced amount of protein is in many cases enough for cells to live a normal and healthy life. The chances of inheriting two copies of rare non-functional alleles increases substantially if the parents are genetically similar. For this reason, among others, consanguineous (i.e. incestuous) relationships are generally taboo.
Ethan Greenblatt, PhD
Sure. Each one acts independently and both make their product, unless one is silenced (turned off).
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Update: June 2012