Identification of a Non-Canonical Ciliate Nuclear Genetic Code Where UAA and UAG Code for Different Amino Acids

• DOI: 10.1101/2022.12.16.520718
• Publication Date: 2022-12-18T05:10:10Z
• Authors: Jamie McGowan; Estelle S. Kilias; Elisabet Alacid; James Lipscombe; Benjamin H. Jenkins; Karim Gharbi; Gemy G. Kaithakottil; Iain C. Macaulay; Seanna McTaggart; Sally D. Warring; Thomas A. Richards; Neil Hall; David Swarbreck
• Keywords: Genetic Code; Stop codon; ENCODE

Abstract The genetic code is one of the most highly conserved features across life. Only a few lineages have deviated from “universal” code. Amongst variants reported to date, codons UAA and UAG virtually always same translation, suggesting that their evolution coupled. Here, we report genome transcriptome sequencing novel ciliate, belonging Oligohymenophorea class, where translation stop changed specify different amino acids. Genomic transcriptomic analyses revealed has been reassigned encode lysine, while glutamic acid. We identified multiple suppressor tRNA genes with anticodons complementary codons. show retained UGA codon enriched in 3’UTR immediately downstream coding region genes, there functional drive maintain tandem Using phylogenomics approach, reconstructed ciliate phylogeny mapped changes, highlighting remarkable number independent changes within Ciliophora group protists. According our knowledge, this first variant