MUTATION AND VARIATION

MUTATION AND VARIATION - germ and soma . Mutations in your...

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MUTATION AND VARIATION Mutation is the ultimate source of variation. Without variation there could be no evolution, so mutations are of great importance to evolution. Important to point out that existing variation can be reshuffled by a variety of mechanisms that we don't always consider as mutations leading to increases or decreases in variation and thus altering the potential for evolution. Mutation = a heritable change . This is often followed by the qualifier "in the DNA" or "in the genetic material". This is redundant with the term "heritable" but points out an important genetic issue: The mutations which are of primary concern are those in the germ line as these are the one that will be passed on. August Weismann was the first to point out the distinction between
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Unformatted text preview: germ and soma . Mutations in your arm or knee cap are not going to get passed on because the germline is sequestered relatively early in development: SOMA SOMA SOMA SOMA GERM / -----> GERM / -----> GERM / -----> GERM / -----> Weismann's doctrine was a serious blow to Lamarkian inheritance of acquired characteristics. However, in plants and some animals (clonal ones in particular) the germline is not sequestered into a single part of the part of the organism so somatic mutations can be inherited (a mutation during the differentiation of a branch on which a flower will develop: all pollen and ovules made by that flower will have a genotype different from the rest of the plant. Think about corals, too)....
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