BIOL 202 Lecture Notes - Lecture 14: Chromosomal Rearrangement, Chromosome Abnormality, Chromosome
3 Dec 2014
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Lecture 14: chromosome changes and rearrangements in human. Many human diseases are caused by mutations in single genes. For an organism or a cell: euploid : aneuploid: a chromosome is over- or under-represented polyploid: diploid : tetraploids: four sets of chromosomes. Rearrangements : an abnormal chromosome (trisomy; genetic imbalance) extra set of chromosomes (plants) two sets of chromosomes (human, mammals) (deletion, translocation, duplication) Using intercalating agents, each chromosome get a specific look (banding pattern). Karyotype : (g banding) 23 human chromosome pairs. 22 autosomal pairs (1-22 ; based on length) + x + y. From the act cytogenetics laboratory manual second edition (1991) Margaret j. barch, editor; chapter 8, figure 4a. And by labelling each chromosome with a specific dye: Congenital malformation (many organs, 90% die within 6 months) Meiosis is the culprit (and differentiates men and women! ) During all these years in meiosis, the chromosomes may become unpaired, and subsequently chromosomes non-disjunction will occur.
