Additional assignment of the human 5S rRNA genes to chromosome region 1q31

A major fraction of the human 5S rRNA genes has previously been assigned to chromosome region 1q42.11-->q42.13 (Sørensen et al., 1991). Through in situ hybridization of different tritiated probes to metaphase spreads, we have demonstrated that a minor fraction of the 5S rRNA genes is localized at band 1q31. This fraction amounts to 25-30% of the genes found in the region 1q42.11-->q42.13. Results obtained with the chromosomes of a balanced translocation carrier involving this region indicate that the major cluster is localized in band 1q42.13.