FIG. 4.

Chromosome copy number changes are frequent in aneuploid strains. Strains RM1000 2, CAI-4 F2, and CAI-4 F3 were transformed by LiOAc-heat shock transformation (A to C), and CAI-4 F3 was transformed by electroporation transformation (D). Chr1 and -2 copy numbers were predicted by quantitative real-time PCR. Because the different strains have different numbers of Chr1 and Chr2 (e.g., CAI-4 F2 parental chromosome copy numbers are two for Chr1 and three for Chr2), purple bars indicate that the transformants have not changed relative to the parental chromosome copy number; green bars indicate that transformants did have a change in chromosome copy number relative to the parent. Over half of the CAI-4 F2 and CAI-4 F3 transformants analyzed had a chromosome copy number that differed from that of the parent, while for nearly all RM1000 transformants, chromosome copy number resembled that of the parent (rightmost columns). CAI-4 F3 transformed by electroporation protocol also exhibited a large number of isolates that had an altered chromosome copy number relative to the parent.