Chapter 9 - Chapter 9 cytogenetics 1 Making a chromosome preparation a Uses cells that will divide in culture i White blood cells ii Fibroblasts

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Chapter 9 : cytogenetics 1. Making a chromosome preparation a. Uses cells that will divide in culture i. White blood cells ii. Fibroblasts iii. Germinal epithelium b. Notes i. Phytohemagglutanin (mitogen) ii. Calchicine ( disables the spindle) c. Steps 2. Chromosome Banding Methods a. Giemsa i. G banding ii. A-T rich regions b. Quinacrine Mustard i. Q bands ii. Fluorescent c. C bands i. Stains centromeres ii. Centromeric hetrochromatin d. R(reverse bands) i. G-C rich regions e. Named by Chromosome, arm, region, band 3. Karyotype a. An organized presentation of a chromosome set i. Human karyotype consists of 22 pairs of autosomes and 1 pair of sex chromosomes ii. Displayed as homologous pairs, from largest to smallest iii. When doing karyotypes there are groups you can place tehm into iv. Groups depend on size or shape 4. Chromatin a. Chromatin= dna + proteins i. Can be in different forms( condensed or uncondensed)
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Chapter 9 : cytogenetics b. Euchromatin i. Undergoes the normal process of condensation and decondensation during the cell cycle ii. Most chromosomal material is euchromatin (including genes) c. Heterochromatin i. Remains highly condensed throughout the cell cycle ii. Found at centromeres, telomeres, and inactive x in femalses iii. Most heterochromatin is transcriptionally inactive (no genes) iv. Constitutive heterochromatin 1. Always heterochromatin v. Facultative heterochromatin 1. Not always heterochromatin 2. Ex: the inactivated X chromosome 5. Euploidy a. Euploid variation is when the chromosome number varies by multiples of the complete haploid set n. i. Monoploid (n); Diploid (2n); triploid (3n); tetraploid (4n); pentaplod (5n); ii. >2n = polyploidy b. Autopolyploid- all of the chromosomes came from the same species c. Allopolyploid- the chromosomes came from different species as a result of hybridization d. Polyploids are: i. Common in plants ii. Fairly common in invertebrates iii. Rare in vertebrates iv. Not viable in mammels e. How polyploidy arises i. Triploid can arise via polyspermy 1. Allow more than one sperm to fertilize the egg ii. Tetraploidy can arise via endomitosis 1. the cell completes karyokinesis, but not cytokinesis iii. Even ploids produce chromosomally balanced gametes (4n, 6n…) 1. Even polyploids are fertile
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This note was uploaded on 06/28/2011 for the course BY 210 taught by Professor Powell during the Summer '08 term at University of Alabama at Birmingham.

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Chapter 9 - Chapter 9 cytogenetics 1 Making a chromosome preparation a Uses cells that will divide in culture i White blood cells ii Fibroblasts

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