Ribosomal RNA genes of Trypanosoma brucei. Cloning of a rRNA gene containing a mobile element

Abstract

An ordered restriotion map of the ribosomal RNA genes of Trypanosome brucei bruoei is presented. Bgl II fragments of T.B.brucei genomio DNA were clomed into pAT 153, and the clones containing rDNA identified. Restriotion maps were established and the sense strands identified. One clone was shown by heteroduplex mapping to contain a 1.1 kb inserted sequence which was demonstrated to be widely distributed throughout the genomes of members of the subgenus Trypanozoon. However, in two other subgenera of Trypanosoma, Nannomonss and Schisotrypanum, the sequence is far less abundant. Analysis of the genomic DNA from two serodemes of T.b.brucel showed that the sequence was present in the rRNA of only one of them, implying that the sequence is a mobile element and that its appearance in rDNA is a comparatively recent occurrence.