Summary
A primary focus of recent research in eukaryotic evolution is the origin of organelles in the eukaryotic cell, particularly mitochondria and plastids. These organelles originated through endosymbiosis, integrating a bacterium into a eukaryotic host. Mitochondria arose from an ancestral alpha-proteobacterium early in eukaryotic evolution. At the same time, plastids originated later from a cyanobacterium and have since spread among eukaryotic lineages via secondary endosymbiosis, wherein a eukaryote engulfs a plastid-bearing alga and retains its photosynthetic machinery. Much work and thought has gone into understanding the endosymbiotic origin of organelles, but very little into how this process goes in reverse. But to understand one, you also need to understand the other. Genomic data from systems where endosymbiotically derived organelles have been substantially functionally reduced or lost entirely show that some of our expectations for what might result at the genomic level are misleading and how this circles back to mislead us about the processes by which the organelles arose in the first place.
Brief biography
Patrick J. Keeling is an evolutionary biologist and professor in the Department of Botany at the University of British Columbia. He was born in Owen Sound, Ontario. He earned a BSc in Genetics from the University of Western Ontario and a PhD in Biochemistry from Dalhousie University. He completed postdoctoral research at the University of Melbourne and Indiana University before joining UBC in 1999. Dr. Keeling studies the phylogeny, genomics, and molecular evolution of protists. His research focuses on the impact of endosymbiosis and horizontal gene transfer on the eukaryotic tree of life. Protists - microbial eukaryotes with complex, nucleus-bearing cells - are central to his work. His discoveries have significantly advanced our understanding of eukaryotic diversity and evolution. Many scientific societies have recognized his contributions across disciplines, including protistology, mycology, phycology, and botany. He has led research networks in microbial biodiversity in programs supported by the Canadian Institute for Advanced Research, the Tula Foundation and the UBC Biodiversity Research Centre. He has served as president of both the International Society of Protistologists and the International Society of Evolutionary Protistology.