1. The mitochondrial genome Nucleoid, 75kb, 10 proteins, tRNA, rRNA, „optional“ introns Relaxed codon usage Variation in the code, trp, met, thr

2. 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

3. Segregation of mitochondrial genes

4. Mitochondrial fusion and fission

6. Non-mendelian determinants 2 µm plasmid, mitochondrial genes, RNA viruses, + prions, cytoplasmatic inheritance    , , Sup35p [URE3], [ure3], Ure2p, deficiency in ureidosuccinate utilization

7. Advantages of meiosis (sexual reproduction) Chromosome mixing, 2 16 =65’536 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

8. meiosis MATa x MAT  MATa/MAT  (2n)  synthesis (4n) -> meiotic div. I - > meiotic div. II -> spores: MATa; MAT  MATa; MAT 

9. 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

10. Bifactorial cross, ie. AB x ab

12. 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

14. If A is linked to the centromere

15. Centromer linkage of A and B

16. 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

17. Resolution of Holiday junction

18. Gene conversion