7th joint conference "Joint Microbiology & Infection Conference 2024" of the DGHM and VAAM

Abstract: Large scale surveys of natural microbial communities (metagenomics) or isolate genomes have revealed species clusters around 95% Average Nucleotide Identity (ANI) of shared genes. That is, members of the same species tend to show >95% ANI among themselves and <85% to members of other species with a clear scarcity (gap) of genome pairs showing between 85-95% ANI. We have recently reported a similar ANI gap within species, around 99.5% ANI, revealing that discrete, intraspecies units may also exist. We suggested referring to these units as genomovars (Rodriguez-R, mBio 2024), and to employ a higher ANI value (99.9%) and level of shared genes (>99% of total genes) to define strains (Viver, Nat. Comms. 2024). To further understand and model these patterns of diversity, however, the underlying genetic and/or ecological mechanisms that maintain discrete units at the species and intraspecies levels need to be elucidated. By analyzing closely related isolate genomes from the same or related samples we show that high ecological cohesiveness among the genomes, coupled to functionally and spatially (across the genome) unrestricted homologous recombination, likely underly these ANI units. Therefore, our results represent a departure compared to previous models of microbial speciation that attributed speciation to either recombination or ecological cohesiveness but not their combined effect. 

What is a species and a strain? The data has shown us the answers!

Salon Echter

Kostas Konstantinidis

Einsätze

Di, 04.06.2024