genome size

Edge evidence

• effective population size regulates reductive genome evolution RO:0002211

  Large Ne strengthens selection against superfluous DNA; small Ne permits drift-driven loss in symbionts.

  • DOI:10.1038/nrmicro3331 Batut et al. compare reductive genome evolution at both ends of the population-size spectrum.
• reductive genome evolution causes genome size biolink:causes

  Reductive evolution sets the observed genome length.

  • DOI:10.1038/ismej.2014.60 Giovannoni et al. link streamlining theory to small genomes in abundant free-living microbes.
• ocean depth positively associated with genome size

  Average genome size of marine communities increases with ocean depth.

  • DOI:10.1038/s41467-023-36988-x Ngugi 2023: AGS increases with depth across epipelagic, mesopelagic and bathypelagic metagenomes.
• soil pH negatively associated with genome size

  Low-pH soils host communities with larger average genomes.

  • DOI:10.1101/2021.11.17.469016 Chuckran 2023: negative AGS-pH relationship in soil; strengthened after microbial-DNA correction (R2 0.32->0.57).
• horizontal gene transfer increases genome size RO:0002213

  HGT is a driving force behind genome expansion, adding accessory gene content.

  • DOI:10.1038/s41559-024-02357-0 Dmitrijeva 2024: HGT described as driving force behind genome expansion; ~42.5% of genes affected by HGT per species.
• mobile genetic elements mediates horizontal gene transfer

  MGEs (plasmids, phages, ICEs, transposons, insertion sequences) carry out HGT.

  • DOI:10.1111/1462-2920.16630 Kogay 2024: MGEs crucial for horizontal gene transfer, including plasmids, ICEs, transposons, IS and phages.
• gene loss decreases genome size RO:0002212

  Loss of protein-coding genes reduces genome length.

  • DOI:10.1038/s41467-024-50368-z Dong 2024: KO-abundance changes track genome size, indicating protein-coding gene loss and genome reduction.
• metabolic versatility positively associated with genome size

  Greater metabolic versatility is correlated with larger genomes.

  • DOI:10.1038/s41564-023-01465-0 Piton 2023: soil bacterial trait axis of metabolic versatility strongly positively correlated with genome size (R2=0.64).