Changes

Merriam-Webster's online dictionary defines a '''mutation''' as  "a relatively permanent change in hereditary material involving either a physical change in [[chromosome]] relations or a biochemical change in the [[codons]] that make up [[Gene|genes]]; also : the process of producing a mutation." [http://www.m-w.com/dictionary/mutation]

 

In [[biology]] '''mutation''' is any physical change in the [[genetic material]] of an [[organism]]. In most cases this is either the [[DNA]] or [[RNA]] in the cell [[nucleus]]. In multicellular organisms there are two primary classes of mutation, [[germline mutations]] and [[somatic mutations]]. Germline mutations are those changes that can be passed down to offspring, while somatic mutations are mutations that only alter genetic material in the mutated organism. There is some evidence that changes outside of the cell's genetic material, such as the [[cytoplasm]], [[proteins]], or the cell [[membrane]] can also be inherited.

 

Mutations can be caused by internal or external factors. Common external factors include [[ultraviolet]] radiation, chemical [[mutagens]], or parasitic organisms (such as [[viruses]] or [[bacteria]]). Most internal causes of mutations stem from errors in reproduction of genetic material. Most of these errors are corrected by error-correcting [[ribosomes]] but some organisms will respond to harsh environments by increasing the rate of mutations. This is known as [[hypermutation]] and is hypothesized to aid organisms by creating wider variation in the [[gene pool]] of the population, increasing the chances that at least some decedents might survive under harsh conditions. 

 

Biology (7th Edition). Neil A. Campbell,Jane B. Reece. http://www.amazon.com/Biology-7th-Neil-Campbell/dp/080537146X.

[[Category:Biology]]

[[Category:Biology]]