On the last common ancestor and early evolution of eukaryotes: reconstructing the history of mitochondrial ribosomes.

摘要: Understanding early evolution is a major challenge for the post-genomic era. A promising way to tackle this issue analyze evolutionary history of key cellular systems through phylogenomic approaches. The current availability genomic data from representatives diverse lineages (especially eukaryotes), together with ever growing number proteomic characterizations now provides ample material apply type analyses trace back origin and three domains life. Here, we have reconstructed composition ancestral mitochondrial ribosome in Last Eukaryotic Common Ancestor (LECA) investigated its subsequent six eukaryotic supergroups. We infer that LECA possessed was already much larger than bacterial ancestor, 19 additional specific proteins, indicating certain amount time occurred between initial endosymbiosis at mitochondrion diversification present-day Subsequently, ribosomes appear undergone very dynamic different lineages, involving loss sets ribosomal protein-coding genes, their transfer host genome, as well acquisition many novel components. This chaotic such fundamental machinery puzzling, especially when compared cytosolic, or chloroplastic ribosomes, which are more stable. Intriguingly, archaeal also show nature, multiple independent losses among lineages.