Figure 8.—

PCR method of detecting very small amounts of JAY291-derived chromosome I in strains with S288c- or YJM789-derived chromosomes. Although the sister spores of JSC2-1-10b and JSC2-1-12d were disomic for chromosome I and contained the JAY291-derived homolog, we could not detect this homolog using SPA. Consequently, to detect very small amounts of this homolog, we designed primers to specifically amplify DNA with this polymorphism. (A) Primer combinations DIST1.1F/DIST1.1R amplify a region ∼12 kb from the centromere of chromosome I. The 3′-end of DIST1.1R anneals to a 4-bp mismatch region that is present only in the JAY291 strain. (B) 1% agarose gel of a PCR products generated with the DIST1.1F/DIST1.1R primer pair. Genomic DNA from JAY291 was diluted into YJM789 genomic DNA in 10-fold serial dilutions from 10⁻¹ to 10⁻⁶ in lanes 3–8. The same analysis is shown with JAY291 genomic DNA diluted into S288c in lanes 11–16. Lanes 17 and 18 contain the products of the same PCR reaction with genomic DNA from spores JSC2-1-10b and JSC2-1-12d, showing that these samples have the JAY291-specific sequence.