Making linkage analysis simple
Making linkage analysis simple
(Do Ch. 5 problems!)
Bakers’ yeast
A single-celled eukaryote
Tetrad analysis
NPD = 4 recombinant progeny
Fig 5.15
Tetrad analysis
Fig 5.15 T = 2 recomb, 2 non-recomb
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 ”
Total # tetrads
4•Total # tetrads
= NPD + 1/2T ”
Fig 5.15
Tetrad analysis example 2
Fig. 5.16
Tetrad analysis example 2
If PD >> NPD, genes are linked.
Fig. 5.16
Tetrad analysis
Fig 5.15
If linked, second law does not hold;<< 50% recombinants
Accurate genetic distances?
“Number of recombinants = NPD•4 + T•2”
“RF = NPD•4 + T•2 ”
Total # tetrads
4•Total # tetrads
= NPD + 1/2T ”
Where’s PD?
The real story: mapping functions
Fig. 5.17
Do Ch. 5, problem 35…
Bread mold
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Mapping centromeric distance
Fig. 5.21
Mapping centromeric distance
Fig. 5.21
Mapping centromeric distance
Fig. 5.21 Number of meioses with second-division patterns = number of crossovers between locus and centromere