Chromosome R

Click here to view the physical map.

The physical map of chromosome R was constructed using the data from 210 probes.  Chromosome R contains 41 Assembly 19 sequence contigs. The minimum size of this chromosome is 2,287,713 bp as determined in the Assembly 20 contig; this includes only one copy of the rDNA. The optical map suggests that the rDNA cluster in strain SC5314 can be large as 349 Kb. The copies on the two homologues are not always the same size, so chromosome R can appear in two places on a CHEF gel, and the largest CHEF band is usually one of the chromosome R homologues. Chromosome R has four SfiI fragments, M+K, U, B, and D in that order. Fragment U contains the ribosomal DNA cistron cluster, there can be as many as 110 copies of this cistron per diploid cell. Chromosome R has one MRS between the K and U Sfi I fragments.  The centromere is about 140 Kb to the left of the rDNA, in contig 19-10057, with a possible lone RB2 another 35 Kb to the left of that.

This is a schematic drawing of the chromosome R of strain 1006. The thin lines are SfiI site, the thick lines are MRS locations.