Predictions: evolutionary trajectories and planet medicine.

The age of synthesis: prediction of bacterial evolutionary trajectories

Conventional scientific wisdom dictates that evolution is a process that is sensitive to many unexpected events and influences, and is therefore essentially unpredictable. On the other hand, considering the bulk of recent knowledge about bacterial genetics and genomics, population genetics and population biology of bacterial organisms, and their sub‐cellular elements involved in horizontal gene transfer, we should eventually face the possibility of predicting the evolution of bacterial evolution. The importance of such type of approach is self‐evident in the case of the evolution of antibiotic resistance, and bacterial–host interactions, including infections. Prediction of bacterial evolution could provide similar clues as weather prediction – higher possibilities of certainty in the closer and more local frames. Indeed, there is a local evolutionary biology based on local selective constraints that shapes the possible local trajectories, even though in our global world, some of these locally originated trends might result in global influences. In the case of adaptive functions (as antibiotic resistance genes in pathogenic bacteria), some of the elements whose knowledge is critical for predicting evolutionary trajectories are: (i) the origin and function of these genes in the chromosome of environmental bacterial organisms; (ii) their ability to be captured (mobilized) by different genetic platforms, and to enter in particular mobile genetic elements; (iii) the ability of these mobile genetic elements to be selected and spread among bacterial populations; (iv) the probability of intra‐host mutational variation and recombination; (v) the probability of re‐combinatorial events among of these and other mobile elements, with consequences in selectable properties and bacterial host‐range; (vi) the original and resulting fitness of the bacterial clones in which the new functions are hosted, including its colonization power and epidemigenicity; (vii) the results of interactions of these bacterial hosts with the microbiotic environment in which they are inserted; and (viii) the selective events, as the patterns of local antibiotic consumption, or industrial pollution, and in general, the structure of the environment that might influence the success of particular complex genetic configurations in which the adaptive genes are hosted (Baquero, 2004). Dealing simultaneously with all these sources of evolutionary variation is certainly a challenge. Such a type of complex structure has evolved along all biological hierarchical levels, creating specific ‘Chinese‐boxes’ or ‘Russian‐dolls’ patterns of stable (preferential) combinations, for instance encompassing bacterial species, phylogenetic subspecific groups, clones, plasmids, transposons, insertion sequences and genes encoding adaptive traits (Baquero, 2008). Assuming a relatively high frequency of combinatorial events, the existing trans‐hierarchical combinations are probably the result on the local availability of the different elements (pieces) in particular locations (local biology), the local advantage provided by particular combinations, and also the biological cost in fitness of some of them. More research is needed to draw the interactive pattern of biological pieces in particular environments (grammar of affinities). Such a complex frame required for predicting evolutionary trajectories (Martínez ) will be analysed (and integrated) by considering heuristic techniques for the understanding of multi‐level selection. The application of new methods – based on covariance, and contextual analysis, for instance using Price's equation derivatives – should open an entirely new synthetic way of approaching the complexity of living world.

The age of planet medicine

Because of the increasing, apparently unavoidable influence of human species on the ecology of our planet Earth, and the necessary counteraction of a modified planet on human health and style of life, the entire planet should be considered as something requiring medical care. The future human medicalization requires the planet medicalization. The refined medical methodology should be escalated to the planet dimension, starting by defining the signs and symptoms of illness, studying the pathogenesis and pathophysiology of planet illness, trying to evaluate their possibilities to invade other regions, establishing specific methods for diagnosis using all available technologies, from genetics to image analysis, and try to make ecological and evolutionary predictions. This will be followed by applying specific interventions (not excluding surgery), treatments, or even isolation procedures and intensive care technology, and recommending or imposing prevention measures. As we are examining the safety of drugs or foods for humans, we should do the same for anything influencing the planet. Of course microbiologists have a big role to start this process – as medical and environmental microbiologists know each other and are progressively closer, and because they have the tradition of being involved in global problems – international health. Microbiologists are also mastering one of the key issues to start with Planet Medicine, the microbial diversity. Changes in microbial diversity might constitute one of the bases of altered planet symptomatology (Baquero, 2003). Of course for starting such a process a totally new way of measuring microbial biodiversity should be developed, forgetting the stupid Linnean way of defining biological evolutionary units (species?). Bacteria cannot have 10 000 species (or less) if Arthropods have 10 000 000. Something is wrong. Population biology and population genetics should be expanded from organisms to any other evolutionary unit. What is clear is the importance of measuring microbial biodiversity, as microbes are critical in the basic functions of Nature, including nutrient recycling. Cyanobacteria constitute up to 70% of the total phytoplankton mass, and are responsible for more that 25% of the total free O2 and about an equivalent proportion of CO2 fixation. Why the changes in size of apparently little Amazonias do not appear every day in the lay press, as the big one? Are we unable to recognize the symptoms leading to biological catastrophes?