Congruence of evidence for a Methanopyrus-proximal root of life based on transfer RNA and aminoacyl-tRNA synthetase genes

A methanogen hosted the origin of the genetic code

“…This is compatible with the suggestion that methanogenesis is a very early pathway in the history of life (Brocks et al, 1999;Battistuzzi et al, 2004;Bapteste et al, 2005;Ueno et al, 2006). Finally, this observation also corroborates the hypothesis that the LUCA was a methanogen (Xue et al, 2005;Wong et al, 2007).…”

Phylogenetic Utility of RNA Structure: Evolution's Arrow and Emergence of Early Biochemistry and Diversified Life

“…Results showed that both Bacteria and Eukarya were each monophyletic, while Archaea was paraphyletic and occupied a basal position in the universal tree. Interestingly, this archaeal rooting of the tree of life again supports previous studies based on tRNA (Xue et al, 2003(Xue et al, , 2005Di Giulio, 2007;Wong et al, 2007;Sun and CaetanoAnoll es, 2008b; F.-J. Sun and G. Caetano-Anoll es, unpublished) and proteomes Wang and Caetano-Anoll es, 2009).…”

“…Since evolution's arrow and the rooting of the tree of life are central and unavoidable issues of evolutionary biology, we discuss how the use of RNA structural evidence can be developed and improved to gain insights into deep evolution of ancient molecules. We will show that these studies consistently and congruently identify the same or similar basal groups in different systems (Xue et al, 2003(Xue et al, , 2005Wong et al, 2007;Sun and Caetano-Anoll es, 2008b;Sun and Caetano-Anollés, 2009). We summarize these results and discuss the tree rooting strategy and the role of thermodynamics in life.…”

“…These observations provide strong support to the very early origin of the archaeal lineage. Moreover, evolutionary studies of transfer RNA (tRNA) also challenged the popular Bacteria-rooting scenario by rooting the tree of life at various groups in Archaea (Xue et al, 2003(Xue et al, , 2005Di Giulio, 2007;Wong et al, 2007;Sun and Caetano-Anoll es, 2008b;Sun and Caetano-Anollés, 2009). To date, the rooting of the tree of life and the origins of diversified life remain controversial, mostly due to our inability to root trees and distinguish between base and crown group taxa that are both extinct and extant (see Chapters 1 and 4) but also because of limited phylogenetic signal in sequences.…”

On the formation of Asp‐tRNAAsn by aspartyl‐tRNA synthetases

“…Evidence supporting CET is multifaceted and continues to grow. Recently Sauerwald et al (7) discovered that the hyperthermophilic archaeal methanogens, which based on their tRNA and aaRS genes are close to LUCA, (4,5) do not have a CysRS, but rely on pretran synthesis from O-phosphoSertRNA Cys for Cys-tRNA Cys production. This important discovery furnishes additional support for the CET postulate that Ser was the precursor for Cys, and the UGN codon box was originally a Ser-family box.…”