Do Vertebrate Gut Metagenomes Confer Rapid Ecological Adaptation?

Recent studies highlight the large impact that gut microbiota has on host biology. The vertebrate gut microbiota is a plastic element that can vary considerably as a response to environmental change. This variation can influence host phenomes. Some gut microbiota changes have been demonstrated to confer benefits to their hosts, which might yield enhanced capabilities to acclimate and adapt to the novel conditions. Measuring the impact of gut microbiota variation on the hosts’ capacity to acclimate and adapt to novel environmental conditions will be necessary to assess the transcendence of gut microorganisms in the evolution of hosts. During times of rapid environmental change, survival of most vertebrate populations depends on their phenomic plasticity. Although differential gene-expression and post-transcriptional processes of the host genome receive focus as the main molecular mechanisms, growing evidence points to the gut microbiota as a key driver defining hosts’ phenotypes. We propose that the plasticity of the gut microbiota might be an essential factor determining phenomic plasticity of vertebrates, and that it might play a pivotal role when vertebrates acclimate and adapt to fast environmental variation. We contemplate some key questions and suggest methodological approaches and experimental designs that can be used to evaluate whether gut microorganisms provide a boost of plasticity to vertebrates’ phenomes, thereby increasing their acclimation and adaptation capacity. During times of rapid environmental change, survival of most vertebrate populations depends on their phenomic plasticity. Although differential gene-expression and post-transcriptional processes of the host genome receive focus as the main molecular mechanisms, growing evidence points to the gut microbiota as a key driver defining hosts’ phenotypes. We propose that the plasticity of the gut microbiota might be an essential factor determining phenomic plasticity of vertebrates, and that it might play a pivotal role when vertebrates acclimate and adapt to fast environmental variation. We contemplate some key questions and suggest methodological approaches and experimental designs that can be used to evaluate whether gut microorganisms provide a boost of plasticity to vertebrates’ phenomes, thereby increasing their acclimation and adaptation capacity. the ability of an individual to adjust its phenome to new environmental conditions to maintain fitness or moderate its loss. the ability of a population or species to adjust biologically so as to accommodate environmental variation by modifying the range of variability that it can cope with. the complete set of DNA of symbiotic microorganisms residing in the animal's gut. the genetic constitution of the specific arrangement of symbiotic microorganisms residing in the animal's gut in a given moment and under certain environmental conditions. community of microorganisms residing in the animal's gut. the complete set of DNA of an organism and its symbiotic microorganisms (host genome + symbiotic organisms’ metagenome). the complete set of nuclear and organellar DNA of the host organism. the specific genetic constitution of the genome of the host organism. the capacity of the gut microorganism community to change its composition (including addition or loss of microbial members and their genes, as well as changes in their relative abundances) or gene-expression pattern in response to the host's physiological changes and variations of the external environment. while all vertebrates have a genome, a gut metagenome and a phenome, each organism has its own genotype and exhibits different metagenotypes and phenotypes depending on genetic, developmental, and environmental conditions. the elements undergoing variation are the metagenome (changing from one metagenotype to another) and the phenome (changing from one phenotype to another). Therefore, we used the terms metagenomic plasticity and phenomic plasticity, rather than metagenotypic plasticity and phenotypic plasticity. the complete collection of observable or measurable physical, biochemical, or behavioral characteristics of organisms, as determined by genomic, metagenomics, and environmental influences. a specific observable or measurable physical, biochemical, or behavioral characteristic (e.g., ear length, blood type, foraging range). a set of phenomic characters related to a given biological or methodological framework (e.g., behavior, nutrition, morphology, energy metabolism). a specific phenome an organism exhibits in a given moment and under certain environmental conditions.