Transfer RNA genes in pieces are an ancestral character

Abstract

Randau & Soll (2008) suggest that the anticodon loop region of transfer RNA (tRNA) genes is the target site of a huge variety of mobile genetic elements and that this resulted in the evolution of tRNA genes in pieces. They therefore suggest that the presence of introns in the anticodon loop might not be a plesiomorphic trait that is important in tRNA origin (Di Giulio, 2006), but an acquired trait, as it endowed tRNA genes with a precious protection mechanism against the integration of viruses and other autonomous genetic elements, in that the intron removed the integration site of these mobile genetic elements. Similarly, Randau & Soll maintain that split and permuted tRNA genes might also have been able to prevent the integration of mobile genetic elements, as their attachment sites were evidently disrupted and hence restricted their propagation within the genome, thus conferring a selective advantage. This evolution should not have been possible …