Evolutionary dynamics of the chromatophore genome in three photosynthetic Paulinella species
Autor: | Sunju Kim, Debashish Bhattacharya, Hwan Su Yoon, Myung Gil Park, Ji-San Ha, Duckhyun Lhee |
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Jazyk: | angličtina |
Rok vydání: | 2019 |
Předmět: |
0301 basic medicine
Symbiogenesis lcsh:Medicine Genome Article Evolution Molecular 03 medical and health sciences 0302 clinical medicine Chromatophores Plastid Paulinella Amoeba Symbiosis lcsh:Science Gene Multidisciplinary biology Endosymbiosis Archaeplastida lcsh:R food and beverages biology.organism_classification 030104 developmental biology Evolutionary biology lcsh:Q Genome Protozoan 030217 neurology & neurosurgery Orthologous Gene |
Zdroj: | Scientific Reports, Vol 9, Iss 1, Pp 1-11 (2019) Scientific Reports |
ISSN: | 2045-2322 |
Popis: | The thecate amoeba Paulinella is a valuable model for understanding plastid organellogenesis because this lineage has independently gained plastids (termed chromatophores) of alpha-cyanobacterial provenance. Plastid primary endosymbiosis in Paulinella occurred relatively recently (90–140 million years ago, Mya), whereas the origin of the canonical Archaeplastida plastid occurred >1,500 Mya. Therefore, these two events provide independent perspectives on plastid formation on vastly different timescales. Here we generated the complete chromatophore genome sequence from P. longichromatophora (979,356 bp, GC-content = 38.8%, 915 predicted genes) and P. micropora NZ27 (977,190 bp, GC-content = 39.9%, 911 predicted genes) and compared these data to that from existing chromatophore genomes. Our analysis suggests that when a basal split occurred among photosynthetic Paulinella species ca. 60 Mya, only 35% of the ancestral orthologous gene families from the cyanobacterial endosymbiont remained in chromatophore DNA. Following major gene losses during the early stages of endosymbiosis, this process slowed down significantly, resulting in a conserved gene content across extant taxa. Chromatophore genes faced relaxed selection when compared to homologs in free-living alpha-cyanobacteria, likely reflecting the homogeneous intracellular environment of the Paulinella host. Comparison of nucleotide substitution and insertion/deletion events among different P. micropora strains demonstrates that increases in AT-content and genome reduction are ongoing and dynamic processes in chromatophore evolution. |
Databáze: | OpenAIRE |
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