Congrats Dani! That's awesome news!

Many thanks to my co-authors @ndombrowski.bsky.social, @luisvalentin.bsky.social, @greening.bsky.social, @tweethinking.bsky.social, and @anja1.bsky.social!

Our results provide insight into a currently understudied DPANN lineage (Caliditerrarchaeota) and highlight similarities and differences in how DPANN halophiles achieved their tolerance to the hypersaline systems they inhabit.

Additionally, using gene trees from ALE analysis, we examined sisterhood rates across all archaea in the dataset. The results confirm higher rates of sisterhood in single gene trees for many DPANN-host pairs and reveal a potential association of Haloaenigmatarchaeaceae with Halarchaeoplasmatales.

However, for both lineages the gene with the highest increase in copy number was the Kef type K+ transporter, implicating this system as key in the adaptation to hypersaline environments for halophilic DPANN.

The results indicate for the Nanohaloarchaeota and Haloaenigmatarchaeaceae different genes were associated with transition to hypersaline environments. For Nanohaloarchaeota this includes oxygen tolerance and DNA repair systems. For Haloaenigmatarchaeaceae this includes a specific Na+ transporter.

Our analysis of public MAGs shows these DPANN are mostly sediment associated thermophiles with no signatures of halophily. We then used gene tree/species tree reconciliations to predict ancestral genome content and compare the two known DPANN halophiles to their last non-halophilic ancestors.