The discovery of new intron-containing human tRNA genes using the polymerase chain reaction

Introns in transfer RNA genes are rare in vertebrates. Until now, the only intron-containing human tRNA genes were believed to be those coding for tRNA(Tyr). All of these introns are inserted 3' to the anticodon position in these genes. We have designed polymerase chain reaction primers that can amplify all of the tRNA(Tyr) genes for cloning and sequencing by using the conserved portions of the gene coding for the structural part of the tRNA. Our preliminary results have revealed five tRNA(Tyr) genes, each of which contains a different intron. We used the same technique to amplify, clone, and sequence the human genes for tRNA(Leu)CAA. This has resulted in the discovery that this human tRNA gene family also has introns inserted 3' to the anticodon. This polymerase chain reaction technique is useful in detecting new families of intron-containing tRNA genes as well as identifying sequence variations in the introns of individual genes.