Imagining a world without species

Categorizing species can get especially hazy at small, microbial scales. After all, the classical definition of species as interbreeding individuals with sexually viable offspring doesn't apply to asexual organisms. Examining shared DNA doesn't help either: collectively, E. coli bacteria have only 20 percent of genes in common. The classification process gets even trickier as many microbes work so closely that it is unclear what to call separate organisms, let alone separate species.

The woes of classification generate contentious debates in the biology community. But, for postdoctoral fellow Mikhail Tikhonov, one field's contentious debate is another's theoretical playground. In new research, he asks: Could organism interactions be described without mentioning species at all?

Key question: “how does evolution act on the structure within a community, rather than on a species?"

This question is not only interesting on a theoretical level, but could have real-world implications in understanding and treating human disease. While some diseases (like pneumonia or meningitis) have specific culprits, many others (like obesity or type II diabetes) seem to be associated to a community-level dysfunction of our microbiome -- the highly diverse bacterial communities that live on and inside our bodies. To understand these diseases, researchers must understand how the system works as a whole.

See:

Mikhail Tikhonov. Theoretical microbial ecology without species. Physical Review E, 2017; 96 (3) DOI: 10.1103/PhysRevE.96.032410

 Posted by Dr. Tim Sandle