Changes

==='''Spontaneous''' [[genetic mutations]]===

==='''Spontaneous''' [[genetic mutations]]===

These mutations change the [[gene]]s within the [[chromosome]]s of the organism and can result in new [[polypeptides]] being produced.  These abnormal polypeptides can have significant affects on the biochemistry of the organism, for example [[sickle cell anemia]] occurs because one [[base]] within the gene for beta-[[hemoglobin]].  Mutations may occur for several reasons such as [[chemical]] [[mutagens]] or exposure to [[ionizing]] [[radiation]], or with no apparent reason.  Although most mutations are harmful due to their random nature (see the example regarding sickle cell anemia), beneficial mutations may also occur.

These mutations change the [[gene]]s within the [[chromosome]]s of the organism and can result in new [[polypeptides]] being produced.  These abnormal polypeptides can have significant affects on the biochemistry of the organism, for example [[sickle cell anemia]] occurs because one [[base]] within the gene for beta-[[hemoglobin]].  Mutations may occur for several reasons such as [[chemical]] [[mutagens]] or exposure to [[ionizing]] [[radiation]], or because of errors made when DNA is copied inside a cell at the first stage of [[mitosis]].  Although most mutations are harmful due to their random nature (see the example regarding sickle cell anemia), beneficial mutations may also occur.

For example, there may be a spontaneous mutation in a [[germline]] ([[gamete]] producing) cell of an agouti (brown) rabbit that changes the allele so that it produces a polypeptide that dyes fur white and produces an [[albino]] rabbit.  There are also alleles that produce chinchilla and Himalayan coats<ref>Biology 2, Jones M. & Gregory J., 2001, Cambridge University Press, ISBN 0-521-79714-4</ref>

For example, there may be a spontaneous mutation in a [[germline]] ([[gamete]] producing) cell of an agouti (brown) rabbit that changes the allele so that it produces a polypeptide that dyes fur white and produces an [[albino]] rabbit.  There are also alleles that produce chinchilla and Himalayan coats<ref>Biology 2, Jones M. & Gregory J., 2001, Cambridge University Press, ISBN 0-521-79714-4</ref>