Genetic characterization of CAI-4 and six histidine auxotrophs (his4.1 to his4.6) obtained by UV treatment. A. Electrokaryotypes. B. Analysis of the heterozygosity of the indicated loci (MTL, RBT7, CZF1, and PHR1). See text for details. Left: A map of Chr4, indicating the location of the several loci (Candida Genome Database), SfiI fragments (Chu et al., 1993) and centromere (elipse) (Sanyal et al., 2004).