The intergenic region between the Vicia faba chloroplast tRNACAA Leu and tRNAUAA Leu genes contains a partial copy of the split tRNAUAA Leu gene

Abstract

A cluster of three tRNA genes located on fragment Bam6a from Vicia faba chloroplast DNA has been sequenced: it contains the genes for tRNA_CAA^Leu, tRNA_UAA^Leu and tRNA^Phe. The two tRNALeu genes are separated by 443 by and are transcribed divergently from different DNA strands. The intergenic region contains a series of short repeats and a partial copy of the split tRNA_UAA^Leu gene which includes 100 by of the 5′ flanking region, 35 by of the 5′ exon and the first 42 by of the intron. It is possible that some of these duplications occurred upon the rearrangement of the two tRNA^Leu genes in broad bean (and in pea) or upon the deletion of one copy of the inverted repeat, since in all other higher plant chloroplast genomes studied so far these two tRNA^Leu genes are located far apart on the genome, one being in the inverted repeat region, the other one in the large single copy region. The tRNA^Phe and tRNA_UAA^Leu are encoded by the same DNA strand, and separated by 110 bp.