The multidisciplinary framework of holobiont biology has flourished to integrate modes of genomic and functional variation that emphasize the centrality of microorganisms to the biosphere and the science of microbiome- based solutions for wide-ranging host activities, spanning agricultural production, conservation biology, and human diseases
Research Summary
In nature, there are no animals or plants without a microbiome, and most microbes are beneficial or harmless to their hosts. As such, the terms holobiont (the collection of host and associated microbial cells) and hologenome (all multispecies genetic material in the holobiont) are important to this new conceptual change because they unify microbial symbiosis into the structure, function, and evolution of macroorganisms. Host organisms are thus defined to contain other organisms—viruses, bacteria, protozoa, and fungi—and their genomes. The functional relevance of these host-microbe associations will vary from inconsequential to harmful or essential, depending on the interactive milieu of members in the holobiont system.
This newly appreciated complexity in host-microbe associations is an inflection point for the life sciences that few could have predicted just a couple of decades ago. A major line of research in our laboratory harkens back to Darwin’s Origin of Species, but in the present-day light of symbiosis. We ask:
- How do closely related animal species vary in their microbial communities?
- Does host genetic variation affect these microbiome differences?
- And what is the role of bacterial symbiosis and microbiomes in animal speciation?
To put this work in context, the origin of species is most often studied with genetic approaches that quantify the number and types of nuclear genes involved in reproductive isolation. Yet in 1927 after discovering that mitochondria were bacterial derived, Dr. Ivan Wallin suggested that bacterial symbionts were fundamental to host evolution. In the 1970’s, Dr. Lee Ehrman showed for the first time that hybrid sterility between fly species could be cured with antibiotics. In the 1990’s, Dr. Lynn Margulis advocated that microbial symbiosis is central to speciation, though she never conducted experiments on this topic. The field then lay dormant with few exceptions. We are now pursuing a comprehensive set of studies on how symbiosis and the microbiome help drive the origin of new animal species.
Select Publications
- Bordenstein, S.R. and the Holobiont Biology Network (2024) The disciplinary matrix of holobiont biology. Science 386(6723): 731-732
- Miller, A.K., C.S. Westlake, K.L. Cross, B.A. Leigh, and S.R. Bordenstein (2021) The microbiome impacts host hybridization and speciation. PLOS Biology 19(10): e3001417
- Van Opstal, E. and S.R. Bordenstein (2019) Phylosymbiosis impacts adaptive traits in Nasonia wasps. mBio 10 (4) e00887-19
- Brooks AW, Kohl KD, Brucker RM, Van Opstal EJ, and Bordenstein SR (2016) Phylosymbiosis: Relationships and functional effects of microbial communities across host evolutionary history. PLOS Biology
PLOS Biology Open Highlight – Evolving as a Holobiont
- Shropshire, J.D. and Bordenstein SR (2016) Speciation by symbiosis: The microbiome and behavior. mBio
- Brucker, RM and Bordenstein SR. (2013) The hologenomic basis of speciation: Gut bacteria cause hybrid lethality in the Genus: Nasonia. Science
- Brucker, RM and Bordenstein SR. (2012) The roles of host evolutionary relationships (Genus: Nasonia) and development in structuring microbial communities. Evolution
- Brucker, RM and Bordenstein SR. (2012) Speciation by Symbiosis. Trends in Ecology and Evolution