Selection Maintains Photosynthesis in a Symbiotic Cyanobacterium Despite Redundancy With its Fern Host.

ABSTRACT: Vertically inherited symbionts experience different physical, chemical, and population genetic environments than free-living organisms. As a result, they can experience long-term reductions in effective population size (Ne) and weaker purifying selection on genes that are less important in the host-associated environment. Over time, these forces result in gene loss. A comparative genomic approach using independently evolved symbiotic bacteria and free-living relatives can reveal which genes are important in the symbiotic state. We apply this approach to understand why some diazotrophic cyanobacteria evolving as vertically inherited symbionts of photosynthetic eukaryotic hosts have lost their ancestral capacity for photosynthesis while others have retained that capacity. We look specificall

SUBMITTER: Friar L 

PROVIDER: S-EPMC12362246 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature