DNA BASE COMPOSITION OF GENUS HANSENULA

The DNA base ratio (GC content) of 46 cultures of Hansenula and allied yeasts which represented 26 species or varieties was studied. The GC content of Hansenula DNA ranged from 28.5 to 46.3%. Intrageneric variation reached 15.6-17.8% in Hansenula sensu Wickerham, 14.4-15.8% in Hansenula sensu Lodder and Kreger-van Rij, 13.4-14.8% in Hansenula emended by Novak and Zsolt, and 11.0-12.7% in Hansenula group (genus) of Tsuchiya et al. The frequency curve of the DNA base ratio demonstrated the presence of two large groups in the genus Hansenula. The first group had relatively high values of GC content with maximal frequency in a range of 40-42%. The second had relatively low values of GC content with the maximal frequency in a range of 32-34%. Species arranged in each line of the phylogenetic scheme of Hansenula proposed by Wickerham exhibited consistent DNA base ratios individually though exceptions were found, and so did the serological groups within Hansenula group (genus) of Tsuchiya et al. A taxonomic and phylogenetic evaluation of DNA base ratio was discussed in relation to the delimitation of the genus Hansenula by several workers and the existence of several groups having similar DNA base ratio within the genus. © 1969, Applied Microbiology, Molecular and Cellular Biosciences Research Foundation. All rights reserved.