The mitochondrial genome Nucleoid, 75kb, 10 proteins, tRNA, rRNA, optional introns
Relaxed codon usage Variation in the code, trp, met, thr Mitochondrial genes Mitochondrial function required to grow on non-fermentable carbon sources, lactate,
glycerol, ethanol Mutations in nuclear genes that affect mito function: PET+ -> pet-
Mutations in mitochondrial DNA Wild-type, + Large deletions, Loss of mito genome, Single site mutations, , mit- (normal translation) Single site mutations, , syn- (deficient in translation)
Mito mutations give 4:0 segregation Segregation of mitochondrial genes
Mitochondrial fusion and fission Zur Anzeige wird der QuickTime Dekompressor Motion JPEG B bentigt.
Zur Anzeige wird der QuickTime Dekompressor Sorenson Video bentigt. Non-mendelian determinants 2 m plasmid, mitochondrial genes, RNA viruses,
+ prions, cytoplasmatic inheritance , , Sup35p [URE3], [ure3], Ure2p, deficiency in ureidosuccinate utilization Advantages of meiosis (sexual reproduction)
Chromosome mixing, 216=65536 possibilities Crossing over -> indefinite number of new combinations (45x2) Gene conversion Gene repair Generation of new alleles 2 different isolates of yeast differ every 100bp
meiosis MATa x MATMATa/MAT(2n)synthesis (4n) -> meiotic div. I -> meiotic div. II -> spores: MATa; MATMATa; MAT Zur Anzeige wird der QuickTime Dekompressor Video
bentigt. Classical genetics Monofactorial cross, ie. A (wt) x a (mut) 2:2 pattern of segregation if 4:0 -> mito
Complementation / non-compl. (in Dipl.) Nonallelic noncomplementation Allelic noncomplementation Supression Bifactorial cross, ie. AB x ab
If A and B are linked PD > NPD The distance of the markers A B determines the number of PD:NPD:T cM = (100/2)[(T+6NPD)/(PD+NPD+T)]
For map distances of up to 4 crossovers (45cM this is ok, >45cM Snow eq.) The number of T is proportional to the map distance If A is linked to the centromere
Centromer linkage of A and B Recombination
General recombination = Homologous recombination Order of events (I meiotic div):
1) Double strand break 2) Two chromatids from different chromosomes (maternal/paternal) cross over 3) Base pairing and strand invasion 4) Synthesis and gap repair
5) Resolution of Holiday junction Resolution of Holiday junction Gene
conversion Gene conversion
