A map of genes encoding the human ribosome. The 22 autosomes and two sex chromosomes are shown as vertical lines, on which are positioned 75 rp genes (RP...), five ribosomal RNA gene clusters (rRNA), and two 5S RNA gene clusters (5SRNA). To the right of each chromosome are listed rp gene STSs, nearby markers, and approximate distances (in centiMorgans and/or centiRays) from the most distal short-arm marker on maps constructed at Généthon and the Whitehead Institute/MIT Center for Genome Research (Hudson et al. 1995). (Maps shown as of November 1997; for updated maps seehttp://www-genome.wi.mit.edu/cgi-bin/contig/phys_map). Because of the inherently statistical nature of RH mapping, we have high confidence in marker orders only where markers are separated by at least 15 centiRays. On distal 19q, for example, RPS5, RPL28,and RPS9 appear to be clustered within 10 centiRays and thus cannot be ordered with confidence. Our present data are most consistent with the order RPS5—RPL28—RPS9—qter (as shown), but higher resolution mapping experiments, while confirming the proximity of the three genes, strongly suggest the order RPS9–RPL28–RPS5–qter (N. Kenmochi, G. Lennon, S. Higa, and L. Ashworth, unpubl.). For the Y chromosome, where no genetic map is available, deletion map intervals (Vollrath et al. 1992) are listed. Our assignment of RPL29 to 3p conflicts with a recent report that it maps to 3q29-qter (Garcia-Barcelo et al. 1997). (*) On chromosome 17, RPL23A andRPL38 were localized to the indicated intervals, but their distances from flanking markers could not be meaningfully estimated.