Chromosomal location of a major tRNA gene cluster of Xenopus laevis

In Xenopus laevis, genes encoding tRNAPhe, tRNATyr, tRNAMet1, tRNAAsn, tRNAAla, tRNALeu, and tRNALys are clustered within a 3.18-kb (kilobase) fragment of DNA. This fragment is tandemly repeated some 150 times in the haploid genome and its components are found outside the repeat only to a limited extent. The fragment hybridizes in situ to a single site very near the telomere on the long arm of one of the acrocentric chromosomes of the group comprising chromosomes 13-18. All the chromosomes of this group also hybridize with DNA coding for oocyte-specific 5S RNA. The tRNA gene cluster is slightly proximal to the cluster of 5S RNA genes.