A Physical Map of Chromosome 7 of Candida albicans

As part of the ongoing Candida albicans Genome Project, we have constructed a complete sequence-tagged site contig map of chromosome 7, using a library of 3840 clones made in fosmids to promote the stability of repeated DNA. The map was constructed by hybridizing markers to the library, to a blot of the electrophoretic karyotype, and to a blot of the pulsed-field separation of the SfiI restriction fragments of the genome. The map includes 149 fosmids and was constructed using 79 markers, of which 34 were shown to be genes via determination of function or comparison of the DNA sequence to the public databases. Twenty-five of these genes were identified for the first time. The absolute position of several markers was determined using random breakage mapping. Each of the homologues of chromosome 7 is approximately 1 Mb long; the two differ by about 20 kb. Each contains two major repeat sequences, oriented so that they form an inverted repeat separated by 370 kb of unique DNA. The repeated sequence CARE2/Rel2 is a subtelomeric repeat on chromosome 7 and possibly on the other chromosomes as well. Genes located on chromosome 7 in Candida are found on 12 different chromosomes in Saccharomyces cerevisiae.