retain a highly conserved, SNP-poor core genome. Analysis of SNPs across depths indicates progressive isolation with burial, while a subset of core genes shows signatures of positive selection. Collectively, the data support depth-associated selection acting alongside drift across Lake Cadagno's persistent sedimentary lineages.IMPORTANCEThroughout the subsurface, multiple examples of "evolutionary stasis" have been reported in microbial lineages that exhibit lower rates of metabolic activity and cellular turnover. This study uses an ~8,000-year sedimentary record of Lake Cadagno to evaluate how persistent populations of cosmopolitan bacteria and archaea have changed with burial and identifies signals of progressive genetic isolation along with positive selection of population-specific subsets of core genes with depth. Together, these changes show that Lake Cadagno's persistent populations are not in stasis but diverge over time and burial.
Rodríguez et al. (Tue,) studied this question.