Table 5: Shared CRISPR spacers between landfill datasets.

Each dataset’s host spacers were dereplicated by CD-Hit at 100% identity for this analysis. Shared spacers required exact matches. Reverse complement matches were included in this analysis.

Dataset	Number of host spacers	Spacers shared with SO_2016	Spacers shared with SO_2017	Spacers shared with NEUS_2019	Spacers shared with CA_2019
SO_2016	5,361	N/A	1,252	162	6
SO_2017	11,812	1,252	N/A	174	10
NEUS_2019	17,581	162	174	N/A	17
CA_2019	7,223	6	10	17	N/A