08-Cytogenetics04 - Outline Variation in chromosome...

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Unformatted text preview: Outline Variation in chromosome structure Single chromatid Cytogenetics Sturtevant Restitution Deletion Single chromosome: dicentric bridge Double breaks in same chromosome Bio 151 Investigations in Genetics and Evolution Prof. Kellar Autumn autumn@lclark.edu Bio 151 - Prof. Autumn 1 Deletion Inversion Double breaks in different chromosomes Variation in chromosome number Bio 151 - Prof. Autumn 2 Outline Variation in chromosome structure Single chromatid Restitution Deletion Calvin Bridges Homologs sometimes do not segregate Single chromosome: dicentric bridge Double breaks in same chromosome Deletion Inversion Double breaks in different chromosomes Variation in chromosome number Bio 151 - Prof. Autumn 3 Credit: DNA From the Beginning; http://vector.cshl.org/dnaftb/asp/ Bio 151 - Prof. Autumn 4 Breakage-fusion-bridge cycle Mitosis or Meiosis II Outline Variation in chromosome structure Single chromatid Restitution Deletion Breakage Single chromosome: dicentric bridge Double breaks in same chromosome Same! Sticky ends Sticky ends Deletion Inversion Fusion Double breaks in different chromosomes Variation in chromosome number Bio 151 - Prof. Autumn 5 Bio 151 - Prof. Autumn 6 Deletion & Inversion Inversion Chromosome Loops During Meiosis I Sticky ends Flip or delete Loop permits 1:1 pairing of homologs Paracentric inversion fuse Bio 151 - Prof. Autumn 7 Bio 151 - Prof. Autumn 8 Loop causes loss of recombinants Loop causes loss of recombinants Pericentric inversion Crossover Reason for cell death: Recombinants Dicentric or Acentric Reason for cell death: Recombinants Imbalanced Survives Dies Survives Bio 151 - Prof. Autumn 9 Bio 151 - Prof. Autumn 10 Dies Outline Variation in chromosome structure Single chromatid Restitution Deletion Double breaks in different chromosomes Chrom #1 Chrom #2 Single chromosome: dicentric bridge Double breaks in same chromosome Deletion Inversion Cross shape during synapsis at meiosis Loci on nonhomologous chromosomes line up Double breaks in different chromosomes Variation in chromosome number Bio 151 - Prof. Autumn 11 Bio 151 - Prof. Autumn 12 Segregation in Translocation Chromosomes Male's Gametes XY Centromeres: XXYY Parental Sterile Bio 151 - Prof. Autumn Sterile 13 Bio 151 - Prof. Autumn 14 Female's Gametes Problems with Triploidy Imbalanced gametes Disruption of sex-determing mechanism? Bio 151 - Prof. Autumn 15 Bio 151 - Prof. Autumn 16 Inversions of R Arm of Chrom. 2 in D. ananassae Majuro (Marshall Is.) Ponape Tutuila (E. Samoa) New Guinea Bio 151 - Prof. Autumn 17 ...
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This note was uploaded on 05/03/2010 for the course BIO 151 taught by Professor Autumn during the Spring '10 term at Lewis and Clark Community College.

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