Mutation
A mutation is any heritable change in the genome of an organism. For a population, heritable mutations provide the source of genetic variation, without which evolution could not occur: If all individuals of a species were genetically identical, every subsequent generation would be identical regardless of which members of the species reproduced successfully. For an individual organism, mutations are rarely beneficial, and many cause genetic diseases, including cancer. For researchers, mutations (either spontaneous or introduced) provide important clues about gene location and function.
Phenotypic Effects and Evolution
Mutations in the germ-line cells are heritable and provide the raw material upon which natural selection operates to produce evolution. Mutations in somatic cells, which are cells that are not germ line, are not heritable but may lead to disease in the organism possessing them.
Most mutations do not cause disease and are said to be "silent" mutations. This is for at least two reasons. First, most DNA does not code for genes, so changes in the sequence do not affect the types or amounts of protein made and there is no change in the phenotype of the organism. Second, most sexually reproducing organisms are diploid, meaning they possess two copies of every gene.
This is a free page. This page contains 201 words. This
article contains 2,432 words (approx. 8 pages at 300
words per page).
Read the rest of this Article with our Mutation Access Pass.
