Lect_6_MutationVariation

Tcgatgat deamina6on of cytosine to uracil occurs

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Unformatted text preview: spots” Certain genomic sequences show higher muta6on rates 2 examples 1. Deamina6on of cytosine to uracil, which then pairs with an adenine: TCGCTGAT AGCGACTA TCGUTGAT TCGUTGAT AGCGACTA TCGATGAT deamina6on replica6on replica6on TCGTTGAT! TCGATGAT! Deamina6on of cytosine to uracil occurs readily. Some genomes recognize and repair uracil within DNA cytosine uracil Determinants of MUTATION pa;erns Muta.onal “hot- spots” Certain genomic sequences show higher muta6on rates 2 examples 2. Repetitive DNA, including repeats of 1, 2, or many base pairs results in “replication slippage” – changes in numbers of repeats ! ! GCAAAAAAAAAAAATG GCAAAAAAAAAAA-TG GCAAAAAAAAAAA-TG! CGTTTTTTTTTTTTAC CGTTTTTTTTTTTTAC CGTTTTTTTTTTT-AC! !!!! replica6on replica6on trinucleo6de repeats: CTG CAG CAG CAG CAG CAT ! ! CTG CAG CAG CAG --- CAT! GTC GTC GTC GTC GTC GTA ! ! GTC GTC GTC GTC --- GTA! Leu Gln Gln Gln Gln His ! ! ! Leu Gln Gln Gln - His !! ! ! ! ! replica6on 2x Determinants of MUTATION pa;erns CAG trinucleo6de repeats and Hun.ngton’s chorea. Dominant allele causes neurologic disorder. CAG encodes glutamine Normal: 6- 35 CAG repeats in gene encoding hun6ng6n protein Disease: >36 CAG repeats – polyglutamine tract causes aggregates of broken proteins in neurons Woody Guthrie singing about his Hun6ngton’s h]p://www.songaweek.com/mp3s/ 02262004_talkinghun6ngton.MP3 Determinants of MUTATION pa;erns How...
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This note was uploaded on 02/10/2014 for the course ECOL 335 taught by Professor Reinthal during the Spring '10 term at Arizona.

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