{"title":"The Last Universal Common Ancestor of Ribosome-Encoding Organisms: Portrait of LUCA.","authors":"Patrick Forterre","doi":"10.1007/s00239-024-10186-9","DOIUrl":null,"url":null,"abstract":"<p><p>The existence of LUCA in the distant past is the logical consequence of the binary mechanism of cell division. The biosphere in which LUCA and contemporaries were living was the product of a long cellular evolution from the origin of life to the second age of the RNA world. A parsimonious scenario suggests that the molecular fabric of LUCA was much simpler than those of modern organisms, explaining why the evolutionary tempo was faster at the time of LUCA than it was during the diversification of the three domains. Although LUCA was possibly equipped with a RNA genome and most likely lacked an ATP synthase, it was already able to perform basic metabolic functions and to produce efficient proteins. However, the proteome of LUCA and its inferred metabolism remains to be correctly explored by in-depth phylogenomic analyses and updated datasets. LUCA was probably a mesophile or a moderate thermophile since phylogenetic analyses indicate that it lacked reverse gyrase, an enzyme systematically present in all hyperthermophiles. The debate about the position of Eukarya in the tree of life, either sister group to Archaea or descendants of Archaea, has important implications to draw the portrait of LUCA. In the second alternative, one can a priori exclude the presence of specific eukaryotic features in LUCA. In contrast, if Archaea and Eukarya are sister group, some eukaryotic features, such as the spliceosome, might have been present in LUCA and later lost in Archaea and Bacteria. The nature of the LUCA virome is another matter of debate. I suggest here that DNA viruses only originated during the diversification of the three domains from an RNA-based LUCA to explain the odd distribution pattern of DNA viruses in the tree of life.</p>","PeriodicalId":16366,"journal":{"name":"Journal of Molecular Evolution","volume":" ","pages":"550-583"},"PeriodicalIF":2.1000,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Molecular Evolution","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1007/s00239-024-10186-9","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/8/19 0:00:00","PubModel":"Epub","JCR":"Q4","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The existence of LUCA in the distant past is the logical consequence of the binary mechanism of cell division. The biosphere in which LUCA and contemporaries were living was the product of a long cellular evolution from the origin of life to the second age of the RNA world. A parsimonious scenario suggests that the molecular fabric of LUCA was much simpler than those of modern organisms, explaining why the evolutionary tempo was faster at the time of LUCA than it was during the diversification of the three domains. Although LUCA was possibly equipped with a RNA genome and most likely lacked an ATP synthase, it was already able to perform basic metabolic functions and to produce efficient proteins. However, the proteome of LUCA and its inferred metabolism remains to be correctly explored by in-depth phylogenomic analyses and updated datasets. LUCA was probably a mesophile or a moderate thermophile since phylogenetic analyses indicate that it lacked reverse gyrase, an enzyme systematically present in all hyperthermophiles. The debate about the position of Eukarya in the tree of life, either sister group to Archaea or descendants of Archaea, has important implications to draw the portrait of LUCA. In the second alternative, one can a priori exclude the presence of specific eukaryotic features in LUCA. In contrast, if Archaea and Eukarya are sister group, some eukaryotic features, such as the spliceosome, might have been present in LUCA and later lost in Archaea and Bacteria. The nature of the LUCA virome is another matter of debate. I suggest here that DNA viruses only originated during the diversification of the three domains from an RNA-based LUCA to explain the odd distribution pattern of DNA viruses in the tree of life.
期刊介绍:
Journal of Molecular Evolution covers experimental, computational, and theoretical work aimed at deciphering features of molecular evolution and the processes bearing on these features, from the initial formation of macromolecular systems through their evolution at the molecular level, the co-evolution of their functions in cellular and organismal systems, and their influence on organismal adaptation, speciation, and ecology. Topics addressed include the evolution of informational macromolecules and their relation to more complex levels of biological organization, including populations and taxa, as well as the molecular basis for the evolution of ecological interactions of species and the use of molecular data to infer fundamental processes in evolutionary ecology. This coverage accommodates such subfields as new genome sequences, comparative structural and functional genomics, population genetics, the molecular evolution of development, the evolution of gene regulation and gene interaction networks, and in vitro evolution of DNA and RNA, molecular evolutionary ecology, and the development of methods and theory that enable molecular evolutionary inference, including but not limited to, phylogenetic methods.