Formation of chimeric genes with essential functions at the origin of eukaryotes

BMC Biology

Debashish Bhattacharya¹  James O. McInerney²  Philippe Lopez³  Jananan S. Pathmanathan³  Eric Bapteste³  Raphaël Méheust³ 

[1] Department of Biochemistry and Microbiology, Rutgers University;Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre;Sorbonne Universités, UPMC Univ Paris 06, CNRS, Evolution Paris Seine - Institut de Biologie Paris Seine (EPS - IBPS);

关键词: Eukaryogenesis;    Evolutionary transition;    Chimeric genes;    Evolutionary genomics;    Endosymbiosis;   

DOI  :  10.1186/s12915-018-0500-0

来源: DOAJ

【 摘 要 】

Abstract Background Eukaryotes evolved from the symbiotic association of at least two prokaryotic partners, and a good deal is known about the timings, mechanisms, and dynamics of these evolutionary steps. Recently, it was shown that a new class of nuclear genes, symbiogenetic genes (S-genes), was formed concomitant with endosymbiosis and the subsequent evolution of eukaryotic photosynthetic lineages. Understanding their origins and contributions to eukaryogenesis would provide insights into the ways in which cellular complexity has evolved. Results Here, we show that chimeric nuclear genes (S-genes), built from prokaryotic domains, are critical for explaining the leap forward in cellular complexity achieved during eukaryogenesis. A total of 282 S-gene families contributed solutions to many of the challenges faced by early eukaryotes, including enhancing the informational machinery, processing spliceosomal introns, tackling genotoxicity within the cell, and ensuring functional protein interactions in a larger, more compartmentalized cell. For hundreds of S-genes, we confirmed the origins of their components (bacterial, archaeal, or generally prokaryotic) by maximum likelihood phylogenies. Remarkably, Bacteria contributed nine-fold more S-genes than Archaea, including a two-fold greater contribution to informational functions. Therefore, there is an additional, large bacterial contribution to the evolution of eukaryotes, implying that fundamental eukaryotic properties do not strictly follow the traditional informational/operational divide for archaeal/bacterial contributions to eukaryogenesis. Conclusion This study demonstrates the extent and process through which prokaryotic fragments from bacterial and archaeal genes inherited during eukaryogenesis underly the creation of novel chimeric genes with important functions.

【 授权许可】

Unknown