ELECTROPHORETIC KARYOTYPES OF PHAFFIA-RHODOZYMA STRAINS

Electrophoretic karyotypes of strains from the astaxanthin-producing y east Phaffia rhodozyma have been established. Intact chromosomal DNA m olecules released from protoplasts were separated by orthogonal field alternation gel electrophoresis (OFAGE) and contour clamped homogeneou s electric field (CHEF). Both small and large chromosomal DNA molecule s were resolved simultaneously by optimizing the running conditions. E lectrophoretic karyotypes among the Phaffia isolates examined differed significantly. Seven to thirteen chromosomal bands, ranging in size f rom 0.83 Mb to 3.50 Mb, were resolved, giving total genome sizes of ab out 15.4 to 23.2 Mb. Ribosomal DNA has been assigned to chromosomal ba nds using a heterologous gene probe.