{"entity": "researcher", "timestamp": "2026-08-20T20:45:58.652Z", "family": "Spang", "given": "Anja", "initials": "A", "orcid": "0000-0002-6518-8556", "affiliations": ["Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden. anja.spang@nioz.nl.", "NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, AB Den Burg, The Netherlands. anja.spang@nioz.nl."], "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/researcher/ee19a6765cb847caac5c440aeb15b509.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/researcher/ee19a6765cb847caac5c440aeb15b509"}}, "publications": [{"entity": "publication", "iuid": "c8f46e1c090a477882811bdc5543949a", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/c8f46e1c090a477882811bdc5543949a.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/c8f46e1c090a477882811bdc5543949a"}}, "title": "Chlamydial contribution to anaerobic metabolism during eukaryotic evolution.", "authors": [{"family": "Stairs", "given": "Courtney W", "initials": "CW", "orcid": "0000-0001-6650-0970", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/ed32f30aa29e4279aef72aed502d2a95.json"}}, {"family": "Dharamshi", "given": "Jennah E", "initials": "JE", "orcid": "0000-0003-4563-3939", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/b742e97795a94ac99217930b27640e3a.json"}}, {"family": "Tamarit", "given": "Daniel", "initials": "D", "orcid": "0000-0002-4940-719X", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/1bc6a5827d7147e097a520745682be8c.json"}}, {"family": "Eme", "given": "Laura", "initials": "L", "orcid": "0000-0002-0510-8868", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/bcca924f04e04ac3a760c09c432064df.json"}}, {"family": "J\u00f8rgensen", "given": "Steffen L", "initials": "SL", "orcid": "0000-0003-0240-7907", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/5e230b212e5248099306b14bc3cedd82.json"}}, {"family": "Spang", "given": "Anja", "initials": "A", "orcid": "0000-0002-6518-8556", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/ee19a6765cb847caac5c440aeb15b509.json"}}, {"family": "Ettema", "given": "Thijs J G", "initials": "TJG", "orcid": "0000-0002-6898-6377", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/6a7921cec2bb45a7a7b0454f41b5f1aa.json"}}], "type": "journal article", "published": "2020-08-00", "journal": {"title": "Sci Adv", "issn": "2375-2548", "volume": "6", "issue": "35", "pages": "eabb7258", "issn-l": "2375-2548"}, "abstract": "The origin of eukaryotes is a major open question in evolutionary biology. Multiple hypotheses posit that eukaryotes likely evolved from a syntrophic relationship between an archaeon and an alphaproteobacterium based on H2 exchange. However, there are no strong indications that modern eukaryotic H2 metabolism originated from archaea or alphaproteobacteria. Here, we present evidence for the origin of H2 metabolism genes in eukaryotes from an ancestor of the Anoxychlamydiales-a group of anaerobic chlamydiae, newly described here, from marine sediments. Among Chlamydiae, these bacteria uniquely encode genes for H2 metabolism and other anaerobiosis-associated pathways. Phylogenetic analyses of several components of H2 metabolism reveal that Anoxychlamydiales homologs are the closest relatives to eukaryotic sequences. We propose that an ancestor of the Anoxychlamydiales contributed these key genes during the evolution of eukaryotes, supporting a mosaic evolutionary origin of eukaryotic metabolism.", "doi": "10.1126/sciadv.abb7258", "pmid": "32923644", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC7449678"}, {"db": "pii", "key": "abb7258"}, {"db": "figshare", "key": "10.6084/m9.figshare.12387980"}], "notes": [], "created": "2026-08-20T11:58:33.078Z", "modified": "2026-08-20T11:58:33.306Z"}, {"entity": "publication", "iuid": "74aed50def0648688ba038dd1da365a3", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/74aed50def0648688ba038dd1da365a3.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/74aed50def0648688ba038dd1da365a3"}}, "title": "Proposal of the reverse flow model for the origin of the eukaryotic cell based on comparative analyses of Asgard archaeal metabolism.", "authors": [{"family": "Spang", "given": "Anja", "initials": "A", "orcid": "0000-0002-6518-8556", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/ee19a6765cb847caac5c440aeb15b509.json"}}, {"family": "Stairs", "given": "Courtney W", "initials": "CW", "orcid": "0000-0001-6650-0970", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/ed32f30aa29e4279aef72aed502d2a95.json"}}, {"family": "Dombrowski", "given": "Nina", "initials": "N"}, {"family": "Eme", "given": "Laura", "initials": "L", "orcid": "0000-0002-0510-8868", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/bcca924f04e04ac3a760c09c432064df.json"}}, {"family": "Lombard", "given": "Jonathan", "initials": "J"}, {"family": "Caceres", "given": "Eva F", "initials": "EF"}, {"family": "Greening", "given": "Chris", "initials": "C", "orcid": "0000-0001-7616-0594", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/1637996ba33748608349dbee48e8fdb9.json"}}, {"family": "Baker", "given": "Brett J", "initials": "BJ"}, {"family": "Ettema", "given": "Thijs J G", "initials": "TJG", "orcid": "0000-0002-6898-6377", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/6a7921cec2bb45a7a7b0454f41b5f1aa.json"}}], "type": "comparative study", "published": "2019-07-00", "journal": {"title": "Nat. Microbiol", "issn": "2058-5276", "volume": "4", "issue": "7", "pages": "1138-1148", "issn-l": "2058-5276"}, "abstract": "The origin of eukaryotes represents an unresolved puzzle in evolutionary biology. Current research suggests that eukaryotes evolved from a merger between a host of archaeal descent and an alphaproteobacterial endosymbiont. The discovery of the Asgard archaea, a proposed archaeal superphylum that includes Lokiarchaeota, Thorarchaeota, Odinarchaeota and Heimdallarchaeota suggested to comprise the closest archaeal relatives of eukaryotes, has helped to elucidate the identity of the putative archaeal host. Whereas Lokiarchaeota are assumed to employ a hydrogen-dependent metabolism, little is known about the metabolic potential of other members of the Asgard superphylum. We infer the central metabolic pathways of Asgard archaea using comparative genomics and phylogenetics to be able to refine current models for the origin of eukaryotes. Our analyses indicate that Thorarchaeota and Lokiarchaeota encode proteins necessary for carbon fixation via the Wood-Ljungdahl pathway and for obtaining reducing equivalents from organic substrates. By contrast, Heimdallarchaeum LC2 and LC3 genomes encode enzymes potentially enabling the oxidation of organic substrates using nitrate or oxygen as electron acceptors. The gene repertoire of Heimdallarchaeum AB125 and Odinarchaeum indicates that these organisms can ferment organic substrates and conserve energy by coupling ferredoxin reoxidation to respiratory proton reduction. Altogether, our genome analyses suggest that Asgard representatives are primarily organoheterotrophs with variable capacity for hydrogen consumption and production. On this basis, we propose the 'reverse flow model', an updated symbiogenetic model for the origin of eukaryotes that involves electron or hydrogen flow from an organoheterotrophic archaeal host to a bacterial symbiont.", "doi": "10.1038/s41564-019-0406-9", "pmid": "30936488", "labels": [], "xrefs": [{"db": "pii", "key": "10.1038/s41564-019-0406-9"}], "notes": [], "created": "2026-08-20T08:55:19.304Z", "modified": "2026-08-20T08:55:19.447Z"}]}