Morgan Gaïa

I am an evolutionary microbiologist interested in viruses and their evolutionary relationships to cellular organisms. I obtained my PhD in Microbiology in December 2013 at Aix-Marseille University in Pr. La Scola’s group, on the isolation and characterization of new giant viruses and related virophages. I then joined Patrick Forterre’s group (Institut Pasteur / Paris-Saclay University) until late 2019 to work on the Tree of Life and the co-evolution between giant viruses and eukaryotes, essentially through phylogenetic and phylogenomic approaches. After two years of postdoc in the LAGE group, I joined the team as a permanent researcher to study the evolutionary, functional, and biogeographical interactions between eukaryotes and their viruses, notably giant viruses.

Evolutionary and functional interactions between eukaryotes and their viruses

Since their discovery in 2003, giant viruses regularly draw the attention of the scientific community over their stunning features, from giant viral particles and genomes to their genomic content. They have shaken the very definition of viruses and led to new concepts, such as the virocell. They nonetheless seem particularly abundant in many environments, especially aquatic ones. They belong to the Nucleocytoviricota (formerly known as the NucleoCytoplasmic Large Dna Virus, or NCLDV assemblage), a group that perfectly illustrates a new vision of the viral world, much wider than before: indeed, the Nucleocytoviricota collectively infect the entire eukaryotic diversity, from marine protists to mammals. Some are infamous for their associated pathologies, such as the Smallpox or the swine fever; others for their implication in important ecologic cycles, notably the carbon pump. They however share an ancient common origin: they could have notably played a major role in the emergence of modern eukaryotes (the viral eukaryogenesis hypothesis), highlighting the often underestimated importance of viruses and cells co-evolution in shaping the diversity of life on our planet. 

This project aims at deciphering the evolutionary and functional interactions between eukaryotes, giant viruses and related elements by leveraging large metagenomic and metatranscriptomic resources. It notably involves exploring the origin and evolution of Nucleocytoviricota and related viruses, the Tree of Life, and the horizontal transfers between viruses and their hosts.

Other LAGE members involved : Tom Delmont, Eric Pelletier, Olivier Jaillon.

Past experiences

2021-nowResearch Scientist (Genoscope, Laboratory of genomic analysis of eukaryotes)
Project: Evolutionary and functional interactions between eukaryotes and their viruses
Research group: Dr. Patrick Wincker
2019-2021Post-doctoral researcher (Genoscope, Laboratory of genomic analysis of eukaryotes)
Project: Evolutionary and functional analyses of marine eukaryotes and giant viruses
Research group:  Dr. Patrick Wincker
2014-2019Post-doctoral researcher (Molecular Biology of Extremophiles; Institut Pasteur – I2BC; Univ. Paris-Sud)
Project 1: Tree of Life reconstruction
Project 2: Evolutionary relationships between giant viruses and eukaryotes
Research group: Pr. Patrick Forterre
2010-2013PhD thesis (Infectious and Emerging Tropical Diseases Research Unit – URMITE; Aix-Marseille Université; France)
Project : Isolation and characterisation of giant viruses and virophages – Director : Pr. Bernard La Scola


  • V Da Cunha, M Gaïa, P Forterre (2022) The expanding Asgard archaea and their elusive relationships with Eukarya. mLife
  • V Da Cunha*, M Gaïa* (*co-first), H Ogata, O Jaillon, TO Delmont, P Forterre (2022) Giant viruses encode actin-related proteins. Molecular Biology and Evolution 39(2), msac022
  • S Kijima, TO Delmont, U Miyazaki, M Gaïa, H Endo, H Ogata (2021) Discovery of viral myosin genes with complex evolutionary history within plankton. Frontiers in Microbiology 12, 1450
  • P Forterre, M Gaïa (2021) Les virus géants et l’origine des ARN polymérases des eucaryotes. Médecine & Sciences 37(3), 230-233
  • H Kaneko, R Blanc-Mathieu, H Endo, S Chaffron, TO Delmont, M Gaïa, N Henry, R Hernandez-Velazquez, C Hao Nguyen, H Mamitsuka, P Forterre, O Jaillon, C de Vargas, MB Sullivan, CA Suttle, L Guidi, H Ogata (2021) Eukaryotic virus composition can predict the efficiency of carbon export in the global ocean. Iscience 24(1), 102002
  • AC Woo, M Gaïa, J Guglielmini, V Da Cunha, P Forterre (2021) Phylogeny of the Varidnaviria morphogenesis module: congruence and incongruence with the tree of life and viral taxonomy. Frontiers in Microbiology 12, 1708
  • P Forterre, M Gaïa (2021) The Origin of Viruses. Encyclopedia of Virology, Fourth Edition 1, 14-22
  • J Guglielmini, AC Woo, M Krupovic, P Forterre, M Gaïa (2020) Reply to Ku and Sun: Ancestors of modern giant and large eukaryotic dsDNA viruses infected proto-eukaryotes. Proceedings of the National Academy of Sciences 117(6), 2749-2750
  • J Guglielmini, AC Woo, M Krupovic, P Forterre, M Gaïa (2019) Diversification of giant and large eukaryotic dsDNA viruses predated the origin of modern eukaryotes. Proceedings of the National Academy of Science 116(39), 19585-19592
  • P Forterre, M Gaïa, V Da Cunha (2019) Engineered bacterium fuels evolution debate. Nature 571(7765), 326-327 -letter
  • M Gaïa, V Da Cunha, P Forterre (2018) Opinion: Archaea is our evolutionary sister, not mother. Scientist 32(6), 23-24
  • P Forterre, V Da Cunha, M Gaïa (2018) Universal tree of life. eLS, 1-7
  • V Da Cunha*, M Gaïa* (*co-first), A Nasir, P Forterre (2018) Asgard archaea do not close the debate about the universal tree of life topology. PLoS Genetics 14(3), e1007215
  • M Gaïa, V Da Cunha, P Forterre (2018) The tree of life. Molecular mechanisms of microbial evolution, 55-99
  • V Da Cunha*, M Gaïa* (*co-first), D Gadelle, A Nasir, P Forterre (2017) Lokiarchaea are close relatives of Euryarchaeota, not bridging the gap between prokaryotes and eukaryotes. PLoS Genetics 13(6), e1006810
  • P Forterre, M Gaïa (2016) Giant viruses and the origin of modern eukaryotes. Current opinion in microbiology 31, 44-49
  • M Gaïa, S Benamar, M Boughalmi, I Pagnier, O Croce, P Colson, D Raoult, B La Scola (2014) Zamilon, a novel virophage with Mimiviridae host specificity. PLoS One 9(4), e94923
  • I Pagnier, DGI Reteno, H Saadi, M Boughalmi, M Gaïa, M Slimani, T Ngounga, M Bekliz, P Colson, D Raoult, B La Scola (2013) A decade of improvements in Mimiviridae and Marseilleviridae isolation from amoeba. Intervirology 56(6), 354-363
  • M Gaïa, I Pagnier, A Campocasso, G Fournous, D Raoult, B La Scola (2013) Broad spectrum of mimiviridae virophage allows its isolation using a mimivirus reporter. PLoS One 8(4), e61912
  • M Gaïa, P Colson, C Desnues, B La Scola (2013) The virophage concept. eLS