Kathryn (Katy) Appler

Diversity, ecology, cell biology and evolution of the Asgard archaea - Nature Reviews Microbiology The Asgard archaea have become a cornerstone of archaeal research, particularly for studies aiming to unravel the origin and early evolution of eukaryotes. This Review outlines the current state of th...

Just over ten years after the discovery of the first Asgard archaeal genomes, we revisit the rapid expansion of this remarkable archaeal lineage. From diverse genomes and metabolisms to eukaryotic signature proteins and the first cultured representatives.
www.nature.com/articles/s41...

Congratulations to Stephan and everyone involved!

Check out his thread to learn more 🧵

Finally out in @natmicrobiol.nature.com: Prediction of eukaryotic cellular complexity in Asgard archaea using structural modelling. Great work by @stephkoe.bsky.social @kassipan.bsky.social @jvhooff.bsky.social

www.nature.com/articles/s41...

Scientists are one step closer to understanding the origins of complex life on Earth after shedding new light on a mystery about our microbial ancestors. https://cnn.it/4srOEWd

Mysterious Asgard microbes may point to origins of complex life | CNN Scientists are trying to understand how complex life emerged on Earth about 2 billion years ago. Our microbial ancestors could be the key.

www.cnn.com/2026/03/04/s...

Can't miss this amazing study on the ribosome structure of the Haloferax archaeon 👏🏼👏🏼👏🏼!! Congrats to my good friend @diorgeps.bsky.social and all the other ppl involved!!

New preprint! We propose "anergiobiosis" to describe microbial life at thermodynamic limits as a way of separating the physiological state from questions about aeonophilic extremophile specialization. ecoevorxiv.org/repository/v...
#Microbiology #Extremophiles #SubsurfaceMicrobiology #MicroSky

Thanks Reinier!!!

Thanks, Pia! Hope you are doing well!!

Thanks!!

Thanks Basile 😊

Thanks Miguel!!

Thanks, Pedro! Congrats to you too!

Thanks, Anthony!!

Oxygen metabolism in descendants of the archaeal-eukaryotic ancestor - Nature Sequencing of marine sediments finds 136 newly identified Heimdallarchaeia and several novel lineages, and indicates that Heimdallarchaeia evolved distinct metabolic capabilities from other Asgardarchaeota, in conditions that may have given rise to early eukaryotes.

Nature research paper: Oxygen metabolism in descendants of the archaeal-eukaryotic ancestor

go.nature.com/4rSfRRw

Oxygen metabolism in descendants of the archaeal-eukaryotic ancestor - Nature Sequencing of marine sediments finds 136 newly identified Heimdallarchaeia and several novel lineages, and indicates that Heimdallarchaeia evolved distinct metabolic capabilities from other Asgar...

#NatMicroPicks

Aerobic archaeal-eukaryotic ancestor? 🦠🫁

The ancestor of eukaryotes may have combined hydrogen metabolism with aerobic respiration, shaping early cellular complexity.

#MicroSky

www.nature.com/articles/s41...

Oxygen metabolism in descendants of the archaeal-eukaryotic ancestor - Nature Sequencing of marine sediments finds 136 newly identified Heimdallarchaeia and several novel lineages, and indicates that Heimdallarchaeia evolved distinct metabolic capabilities from other Asgar...

Hot eukaryogenesis news (is there any other kind?) - hydrogen production and aerobic respiration may have been present in the Asgard-eukaryotic ancestor - paper in @nature.com www.nature.com/articles/s41...

Thanks, I cannot wait for our next project! 😊

Oxygen metabolism in descendants of the archaeal-eukaryotic ancestor - Nature Sequencing of marine sediments finds 136 newly identified Heimdallarchaeia and several novel lineages, and indicates that Heimdallarchaeia evolved distinct metabolic capabilities from other Asgar...

New research in @nature.com funded by our Life Sciences division: "Oxygen metabolism in descendants of the archaeal-eukaryotic ancestor." https://www.nature.com/articles/s41586-026-10128-z

Thanks for all of your wonderful work on this project! I very much enjoyed working together and hope we can again soon!

Eukaryogenesis in light of an expanded catalogue of Asgard genomes. a, Simplified, scaled timeline spanning from before the Last Asgard archaea Common Ancestor (LAsCA) to today. Thin bands mark predicted time ranges of relevant events (for example, GOE), thicker bands represent processes (for example, eukaryogenesis), and brackets indicate the period shown in b. The timeline further highlights milestones, including potential early eukaryotic fossils60 and the modern-day co-occurrence of Heimdallarchaeia and Alphaproteobacteria observed in this study (interaction likely originated earlier).

Fig. 1 | Expanded genomic diversity of Asgard archaea. a, Maximum-likelihood phylogeny based on 47 non-ribosomal markers (NM47)using the WAG + C10 + R4 model with 100 nonparametric bootstrap pseudoreplicates, including 869 Asgardarchaeota MAGs and 309 outgroup genomes. The blue branches (lower right) indicate the new Asgardarchaeota classes, Ranarchaeia, and the recently proposed Asgardarchaeia4. The concentric rings denote (in to out): the predicted genome size, metabolic guilds based on Pfam clustering, sampling locations, and black stars on the outside mark MAGs added by this study. Asgard, Asgardarchaeia; Atabey, Atabeyarchaeia; Baldr, Baldrarchaeia; Frey/Jord, Frey/Jordarchaeia; Gerd, Gerdarchaeales; Heimdall, Heimdallarchaeaceae; Hel, Helarchaeales; Hermod, Hermodarchaeia; Hod, Hodarchaeales; Kari, Kariarchaeaceae; Loki, Lokiarchaeales; Njord, Njordarchaeales; Odin, Odinarchaeia; Ran, Ranarchaeia; Sif, Sifarchaeia; Thor, Thorarchaeia; Wukong, Wukongarchaeia. b, SR4-recoded phylogeny of the same genome set inferred with the model GTR + C60 + G and 100 nonparametric bootstrap pseudoreplicates (Methods). This updated catalogue constitutes a large increase in the medium- to high-quality publicly available genomes (completeness >50% and contamination and redundancy <10%) with 65.3% from the Guaymas Basin and 34.7% from the Bohai Sea. The encircled numbers represent MAGS added by this study. The scale bars in bothsubpanels represent the average number of substitutions per site.Map created in BioRender; Appler, K. https://biorender.com/147ieoc(2025).

Our work is published today: ‘Oxygen metabolism in descendants of the archaeal-eukaryotic ancestor’. This was a huge effort lead by @katyappler.bsky.social. Extremely grateful to have been a part of this amazing project! 😊🦠🧬

Links: www.nature.com/articles/s41...
www.nature.com/articles/s41...

I will add if there's any wonder how much work this study was just have a look at the 170 pages SI file! static-content.springer.com/esm/art%3A10...

Research centers in the Great Lakes region change the scope of global freshwater ecology | Great Lakes Echo A new study examines the uniqueness of work that research centers conduct in the Great Lakes region, highlighting their importance amid dramatic changes in federal funding.

new study of #GreatLakes research centers, w/ some nice quotes from CIGLR colleagues: "Research centers in the region also work together as a collaborative that complements each of them, and so the network of research centers is vital, Moerke said."...

greatlakesecho.org/2026/02/16/r...

A Break in a Longstanding Mystery about Origin of Complex Life Breathe easy. It appears our microbial ancestors used oxygen, too.

Some of our earliest microbial ancestors, the Asgard archaea, were able to use oxygen, says new study in @nature.com. It may solve a mystery about how complex life first arose.

#AsgardArchaea #MicrobialEcology #Eukaryogenesis #TexasScience @utmsi.bsky.social @archaeal.bsky.social

A pilot in a submersible vehicle collecting sediments samples in 30 meters of water looking for Asgards (microbial relatives of eukaryotes)

One of the biggest questions in biology is how complex cells evolved about 2 billion years ago. Here's my new story on how scientists are solving the mystery of eukaryotes like us. Gift link: nyti.ms/4qMbo22

Finally out in @nature.com: a new piece of the puzzle of how complex life evolved. Lead by @archaeal.bsky.social & @katyappler.bsky.social. Great collab with @greening.bsky.social and @kassipan.bsky.social. More pieces to follow soon! www.nature.com/articles/s41...

How Microbes Got Their Crawl

Check out some of our research 🤯

How Microbes Got Their Crawl www.nytimes.com/2026/02/18/s...

New paper from my team detailing a greatly expanded genomic database of Asgard archaea revealing of high energy metabolism those related to eukaryotes! Led by @katyappler.bsky.social lots of help from @jameslingford.bsky.social @valdeanda.bsky.social @kassipan.bsky.social doi.org/10.1038/s415...

Oxygen metabolism in descendants of the archaeal-eukaryotic ancestor - Nature Sequencing of marine sediments finds 136 newly identified Heimdallarchaeia and several novel lineages, and indicates that Heimdallarchaeia evolved distinct metabolic capabilities from other&nbsp;Asgar...

At long last! Check out the link to our publication in@nature.com to learn more. doi.org/10.1038/s415...

I am grateful for how far this work has come and excited to see the story continue to unfold. I look forward to what we might discover next!
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