Karyotype and isozyme profiles do not correlate in Kluyveromyces marxianus var. marxianus

Diverse karyotypes were found for Kluyveromyces marxianus var. marxianus (anamorph = Candida kefyr) when analysed by pulsed-field gel electrophoresis. Two classes were discernible. One class was represented by six or seven chromosome-sized bands ranging from 1000 to 2400 kbp, the other by 9–17 bands including both smaller and larger pieces of DNA. The isozyme and protein profiles of K. marxianus var. marxianus were distinct from those of K. lactis. Two strains, originally derived from the same isolate of K. marxianus var. marxianus, showed identical isozyme patterns but slightly differing karyotypes. For identification of K. marxianus var. marxianus, the isozyme profiles provide a more stable character than the electrophoretic karyotypes.