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#TreeOfLife

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Lukas VFN 🇪🇺

Scientists figure out why there are so many colorful #birds in the #tropics and how these colors spread over time phys.org/news/2024-07-scientis

Transitions between colour mechanisms affect speciation dynamics and range distributions of birds nature.com/articles/s41559-024

"They found that iridescent, colorful feathers originated 415 times across the #bird #TreeOfLife, and in most cases, arose outside of the tropics– and that the ancestor of all modern birds likely had iridescent feathers, too"

photo of a tropical bird with iridescent feathers
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Frank Aylward

Happy to share the latest manuscript from our lab, in which we propose that eukaryotes evolved from a genomic chimera of Asgard archaea and giant viruses.

biorxiv.org/content/10.1101/20

This is a controversial topic, but we believe we have strong evidence to suggest a critical viral role in eukaryogenesis.

bioRxiv · Chimeric Origin of Eukaryotes from Asgard Archaea and Ancestral Giant VirusesThe details surrounding the evolution of complex cells remain some of the most enduring mysteries in biology. Recent evidence has demonstrated that Asgard archaea are the closest cellular relatives of eukaryotes, but several eukaryotic enzymes involved in key cellular processes lack phylogenetic affinity with archaea. In particular, phylogenies of eukaryotic DNA and RNA polymerases often support a 3-domain topology that is not consistent with an archaeal origin. Here we present comprehensive phylogenetic analysis of eukaryotic family B DNA polymerases and multimeric RNA polymerases and show that these core subunits of these enzymes are derived from the ancestors of modern giant viruses (phylum Nucleocytoviricota). Specifically, we show that the eukaryotic delta polymerase (Polδ), a key processive polymerase required for genome replication in all eukaryotes, clusters within an ancient viral clade, strongly supporting a viral origin. By contrast, the other eukaryotic processive polymerase (Polε), clusters within an Asgard archaeal clade. Together, these observations provide a strong and direct link between early eukaryotes, Asgard archaea, and giant viruses. Lastly, we provide a comprehensive phylogenetic analysis of eukaryotic multimeric RNA polymerases to confirm that RNA polymerase II, which is responsible for mRNA transcription in eukaryotes, is also derived from the ancestors of modern giant viruses. In total, our results support a model of eukaryogenesis in which complex cells emerged from a genomic chimera of Asgard archaea and an ancient viral lineage. ### Competing Interest Statement The authors have declared no competing interest.
#viruses#protists#eukaryotes
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