Changes

In [[biology]], a '''mutation''' is any physical change in the [[gene]]tic material of an [[organism]]. In most organisms, including humans, the genetic material is [[DNA]], while some viruses use [[RNA]]. Mutations can be caused by internal or external factors. 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. Somatic mutations are the root cause of [[cancer]]. 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.  

In [[biology]], a '''mutation''' is any physical change in the [[gene]]tic material of an [[organism]]. In most organisms, including humans, the genetic material is [[DNA]], while some viruses use [[RNA]]. Mutations can be caused by internal or external factors. 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. Somatic mutations are the root cause of [[cancer]]. 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.  

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.  

Common external factors include [[ultraviolet]] radiation, chemical [[mutagen]]s, or parasitic organisms (such as [[viruses]] or [[bacteria]]). Most internal causes of mutations stem from errors in reproduction of genetic material.  

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 descendents might survive under harsh conditions. Hypermutation also occurs in the human [[immune system]], so that our antibodies have more variation and can respond to a greater variety of invaders.  

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 descendents might survive under harsh conditions. Hypermutation also occurs in the human [[immune system]], so that our antibodies have more variation and can respond to a greater variety of invaders.