EVOLUTION/LECTURE1file:///E|/CH5-MUTATION-SPRING-2008/CHAPTER_5_SPR_2008.html[12/8/2011 2:29:34 PM]Evolution(PCB 4674).Chapter 5. Mutations and genetic variation 1Main topics of lecture:I: Mechanisms responsible for generating new genes and new alleles1.- Introduction2.- Where new alleles come from3.- Where new genes come fromII: Chromosome alterations:4.- Inversions5.- PolyploidyIII: Measuring genetic variation in natural populations6.- Genetic variation in natural populations: An introduction7.- Determining genotypes using DNA8.- How much genetic diversity exists in a typical population?I: Mechanisms responsible for generating new genes and new alleles1.- Introduction1.1.- Mutations are the raw material of evolution. Without mutation there are no new genes,no new alleles, and eventually no evolution. Mutation is the ultimate source of the heritablevariation acted upon by natural selection and other evolutionary processes2.- Where new alleles come from2.1.- The instructions for making and running an organism are encoded in its heritablematerial: the molecule called deoxyribonucleic acid, or DNA. DNA is made ofdeoxyribonucleotides. Each on them contains:- 5-carbon sugar called deoxyribose- A phosphate group- A distinct nitrogen-containing base [Pyrimidines (Cytosine & Thymine) orpurines (adenine & guanine)- The four deoxyribonucleotides are routinely abbreviated to C, T, A, and Gdepending on their distinct nitrogen bases2.2.- Deoxyribonucleotides are linked by phosphodiester bonds that form between the
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