Figure 3: Limited, yet widely dispersed biogeographic distribution of ‘Ca. Kryptonia’ genomes and CRISPR spacers.

All genomic content from the ‘Ca. Kryptonia’ GFMs and SAGs was used to comprehensively search the collection of 640 Gb of assembled metagenomic data from 4,290 environmental samples, including 169 samples from geothermal springs and hydrothermal vents denoted by red triangles (temperature ⩾50 °C). Marked circles are as follows: (A) Great Boiling Spring, Nevada^20,21; (B) Dewar Creek Spring, Canada¹⁹; (C) Jinze pool, Yunnan Province, China²²; and (D) Gongxiaoshe pool, Yunnan Province, China²². Significant matches were determined for sequences ⩾250 bp in length and with ⩾75% identity threshold for non-ribosomal genomic regions. For metagenomic contigs mapping to the ‘Ca. Kryptonia’ ribosomal operon, a 97% identity threshold was used to capture only high-quality matches to ‘Ca. Kryptonia.’ For CRISPR spacers, only significant matches allowing for up to 3 bp mismatch along the entire length of the spacer were considered. The ‘Ca. Kryptonia’ genomic hits can be found in Supplementary Data 4 and the manually curated spacer hits can be found in Supplementary Data 3.