User:Knarfy/mt-tRNA Enoplea

Armless mt-tRNAs in Enoplea (Nematoda)
Mitochondrial transfer RNAs (mt-tRNA) are RNA molecules that are required for the protein biosynthesis in mitochondria. Animal mitogenomes usually encode 22 mitochondrial tRNA genes. In contrast to their nuclear counterparts, mitochondrial tRNA evolve rapidly at sequence level and exhibit a variety of deviations from the common clover-leaf structure. Such "bizarre" mitochondrial tRNAs with incomplete clover-leaf structures have long been known in particular in the Nematoda. For example, in Caenorhabditis elegans, 20 of the 22 mt-tRNA are T-armless, and the two serine tRNAs lack the D-arm.

Computational studies of Enoplea mitogenomes discovered aberrant mitochondrial tRNA genes that have a length of only about 40 nucleotides. They lack both the D- and T-stem. Instead, these short mt-tRNA sequences formed D- and T-stem replacement loops and share only the acceptor stem and the anticodon stem with common tRNA sequences.

These armless, minimal mt-tRNAs code for Alanine, Arginine, Asparagine, Cysteine, Histidine, Isoleucine, Phenylalanine, Threonine, Tyrosine, and Valine. While not all Enoplea have the same set of degenerated genes, the members of the genus Romanomermis share 9 of the 10 genes in the aberrant genes.