How many rDNA repeats are in the systematic sequence, and how are they represented?
When the systematic sequencing of the yeast genome was performed, only two repeats of the rDNA region on chromosome XII were sequenced. The RDN5, RDN37, RDN58, RDN25, and RDN18 loci shown on the chromosomal map are meant to represent an rDNA repeat unit. RDN37 represents the primary transcript that is processed into the 25S, 18S and 5.8S rRNAs. RDN25, RDN18, and RDN58 represent the 25S, 18S, and 5.8S rRNAs, respectively, and RDN5 represents the 5S rRNA. RDN1 is a Locus entry that represents an entire rDNA region, but it does not have associated sequence or position information and does not appear on the map.
