Genetics-Gene Expression

Genetics-Gene Expression - Genetics Exam next Tuesday H/wk...

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Genetics- 11/6/07 * Exam next Tuesday * H/wk due this week is from Dangl’s pp lecture from Thursday * Bacterial genetics, phage, regulation, today’s stuff, etc. is on next exam ** Gene Expression ** -transcription, recombination, gene conversion, epigenetics, …? study all of these by mating type (yeast) (interconversion) How does a single cell convert mating type? yeast come in 2 types: a and alpha they divide as haplotype: 1-2-4 exponential growth - so as a single celled organism what is a life strategy for you to increase your survival? to become diploids! (instead of haploids, which is what these yeast are, so as to be able to express recessive traits) how do u do this?: switch your own mating type ( mating type interconversion: converting one mating type into another for a single celled organism to go from haploid to diploid organism) many fungi don’t have separate chromosome to determine sex (like we do) its determined by a couple of genes on a chromosome (determined by a and alpha) so how do you interconvert? u must more info on sex determination somewhere else in the chromosome (HMLalpha and HMRa 1 is on the left arm and the other is on the right arm of the chromosome) usually the MATa gene is active and determines sex? And the HMLalpha and Ra are kept inactive if they weren’t silent, the haploid cell would be a/alpha as well (i.e. it would look just like a diploid cell) so they mating type is MATa its got info for alpha hanging out on the left side of it and info for HMRa on the right side diploid cell a/alpha (an a/alpha diploid?)? so what a single celled organism must go change mating type HOW? by crossovers or some sort of recombination so ur MATa and u wanna switch to MATalpha u need homology (but the a and alpha and MATa do have a lot of homology as is, so we’re good) they need to know right vs. left (i.e. which side to recombine with) (if it was MATa and tried to recombine with the side that had the HMRa gene, it would be futile b/ c you’re already a!!) thus, the cell knows how to differentiate b/w left and right!! thus, it must know something about the structure of the chromosome!! (its not determining this just by reading the info) if ur MATalpha u always get ur info from the right and if ur MATa u always get ur info from the left during recombination so to start this whole process u need to make a nick or a double strand cut
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This note was uploaded on 03/26/2008 for the course BIOL 202 taught by Professor Kieber-hogan during the Fall '08 term at UNC.

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Genetics-Gene Expression - Genetics Exam next Tuesday H/wk...

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