Lecture 7

Lecture 7 - Lecture 6 Mutations The nature of mutation What is a genetic change in terms of DNA How do mutations affect genes and how do we use

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Unformatted text preview: Lecture 6 31/1/08 Mutations The nature of mutation What is a genetic change in terms of DNA? How do mutations affect genes, and how do we use them to interpret gene function? The range of genetic variation Change in genome copy number (ploidy); change in chromosome number (aneuploidy); chromosome mutations; gene mutations ( ‘ point mutations ’ ). Types of point mutation: base pair substitutions. Know the difference between transition and transversion. Insertions and deletions (indels). Trinucleotide repeat expansion. How mutations affect genes: missense and nonsense changes. Resistance of genetic code to transitions. Mutations, alleles and polymorphisms. How do mutations arise? Mutagenesis Muller 1927: discovery that X-rays are mutagenic 1. “Spontaneous mutation” a. Errors in DNA replication (tautomers? wobble pairing?) (rare: error rate 1 in a billion) b. Spontaneous chemical changes e.g. depurination, deamination 2. Chemical mutagens (many kinds) a. Base modiFers e.g. Ethyl methane sulfonate. a....
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This note was uploaded on 05/31/2009 for the course BICD 100 taught by Professor Nehring during the Spring '08 term at UCSD.

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