HMB265H1 Chapter Notes - Chapter 18: Homologous Chromosome, Transposable Element, Karyotype
19 Nov 2017
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HMB265H1 Full Course Notes
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Hmb265 lecture 18 readings - changes in chromosome structure. Mouse chromosome has several pieces of chromosomes from humans + vice versa. Ex: mouse chromosome 1 has sequences on human chromosomes 1, 2, 5, 6. = could construct mouse genome by breaking human genome up. Reorganize dna sequences within one or more chromosomes. Can affect gene activity/transmission by altering position, order of genes. Not b/c rearrangements + changes in chromosome # occur infrequently (b/c occur a lot) B/c genetic instabilities + imbalances produced by changes = selective disadvantage. Closely related spp differ by a few rearrangements. Distantly related spp differ by a lot of rearrangements. = there is correlation between karyotypic rearrangements + evolution of new spp. Reciprocal translocations = 2 non homologous chromosomes exchange parts) Chromosomal rearrangements are caused by dna breakage or aberrant crossing- over between repeated sequences. 2 events to cause (deletions, duplications, inversions, recip trans): [2] aberrant recombination at sites of repeated dna sequences.
