classification of mutations T. 23 final exam.txt

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classification of mutations T. 23 final exam.txt
2011-12-11 11:15:02
mutation classes

evol bio
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  1. Point mutations
    • single nucleotide substitution
    • a. transition: pur-->pur, pyr-->pyr (4 types)
    • b. transversion: pur-->pyr etc (8 types)
  2. Frameshift
    nucleotide insertion or deletion: causes nonsynonymous substitution (if in exons)
  3. Deletion
    • Loss of spacers: Not even transcription
    • Loss of introns: no translation
    • Loss of exon: no protein coding
    • or gene or chromosome loss (during recombination)
  4. Duplication
    • Gain of introns, exons or spacers (during recombination or transposable elements)
    • Tandem: gene duplicated tandemly, ie ABCDE chromosome adds ABBCDE in that order on the chromatid
    • Transposition: gene duplicated not next to itself, ie AB-CDE chromatid adds B at location under C so now chromatid is AB-CBDE
  5. Inversion
    • Reversal of normal chromosomal 5-3' direction of some DNA seq (during recomb or transposition)
    • Paracentric: NOT involving Centromere, ie AB-CDE chromatid (- is centromere) is now BA-CDE
    • Pericentric: involving Centromere, ie AB-CDE becomes AC-BDE
  6. Translocation
    • Movement of chromosomal regions to different chromosomes to DIFFERENT chromosomes (usually by transposition)
    • Reciprocal: the loss of one to another chromosome is reciprocated, ie AB-CDE + F-GH becomes FB-CDE + A-GH
    • Non-Reciprocal: ie, AB-CDE + F-GH becomes B-CDE + AF-GH