Lecture.19.Fall.2013

Find or create mutations that affect different

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Unformatted text preview: so good and/or useful: – Source of genetic variation and the raw material of evolution no mutation=no evolution – Mutations have been used to unravel the principles of inheritance • Gregor Mendel and different garden pea variants • Thomas Hunt Morgan and mutant fruit flies The importance of mutations Mutations are useful for probing fundamental biological processes 1. Find or create mutations that affect different components of a biological system 2. Map the mutation to identify the mutant gene 3. Leads to an understanding of the genes that regulate the system and an understanding of the biological process. 4. Analogous to figuring out how an automobile works by breaking different parts of a car and observing the effects. •e.g. break the radiator and the engine overheats, indicating that a functional radiator cools the engine. Categories of mutations: germline vs. somatic nonreprodutive, not passed on to offspring, not gamete gametes, can be passed on every single cell will carry that mutation • When we speak of mutations: • we are usually speaking of germ-line mutations • in cells that produce gametes. • These affect all cells in the resulting organism Categories of mutations • Somatic cell mutations: • cannot be passed on to the next generation • frequently do not have a large effect on phenotype. • Somatic mutations that stimulate cell division can increase in number and spread. • This is the basis for all cancers. Chromosome rearrangements vs. single-gene mutations • Chromosome rearrangements: large-scale genetic alterations that affect chromosome structure or the number of chromosomes. aneuploidy, translocation, deletions, ect • Single-gene mutations: relatively small DNA lesions that affect a single...
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This document was uploaded on 02/25/2014.

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