Making linkage analysis simple

Making linkage analysis simple (Do Ch. 5 problems!)

Bakers’ yeast A single-celled eukaryote

Haploid and diploid Fig. 5.14

Haploid and diploid Clonal (mitotic) growth Fig. 5.14

Haploid and diploid Fig. 5.14

Haploid and diploid Fig. 5.14

Why yeast?

Tetrad analysis Fig 5.15

Tetrad analysis Fig 5.15

Tetrad analysis Cannot make histidine Cannot make tryptophan Fig 5.15

Tetrad analysis Fig 5.15

Tetrad analysis Fig 5.15

Tetrad analysis Fig 5.15

Tetrad analysis Fig 5.15

Tetrad analysis Fig 5.15

Tetrad analysis Fig 5.15 NPD = 4 recombinant progeny

Tetrad analysis Fig 5.15

Tetrad analysis Fig 5.15 T = 2 recomb, 2 non-recomb

Tetrad analysis example Fig 5.15

Tetrad analysis example “Number of recombinants = NPD•4 + T•2” Fig 5.15

Tetrad analysis example “Number of recombinants = NPD•4 + T•2” “RF = NPD•4 + T•2 ” 4•Total # tetrads Fig 5.15

Tetrad analysis example “Number of recombinants = NPD•4 + T•2” “RF = NPD•4 + T•2 ” 4•Total # tetrads = NPD + 1/2T ” Total # tetrads Fig 5.15

Tetrad analysis example 2 Fig. 5.16

Tetrad analysis example 2 Fig. 5.16 If PD >> NPD, genes are linked.

Tetrad analysis If linked, second law does not hold; Fig 5.15 If linked, second law does not hold; << 50% recombinants

Tetrad analysis What if two crossovers? Fig 5.15

Accurate genetic distances? “Number of recombinants = NPD•4 + T•2” “RF = NPD•4 + T•2 ” 4•Total # tetrads = NPD + 1/2T ” Total # tetrads Where’s PD?

The real story: mapping functions Fig. 5.17 Do Ch. 5, problem 35…

Bread mold

Bread mold Fig. 5.14

Bread mold Each pair is identical Fig. 5.14

Mapping centromeric distance Fig. 5.21

Mapping centromeric distance Fig. 5.21

Mapping centromeric distance Number of meioses with second-division patterns = number of crossovers between locus and centromere Fig. 5.21