Multilevel research strategies characterize contemporary molecular inquiry into biological systems. We outline conceptual, methodological, and explanatory dimensions of these multilevel strategies in microbial ecology, systems biology, protein research, and developmental biology. This review of emerging lines of inquiry in these fields suggests that multilevel research in molecular life sciences has significant implications for philosophical understandings of explanation, modeling, and representation.

Science is now studying biodiversity on a massive scale. These studies are occurring not just at the scale of larger plants and animals, but also at the scale of minute entities such as bacteria and viruses. This expansion has led to the development of a specific sub-field of “microbial diversity”. In this paper, I investigate how microbial diversity faces two of the classical issues encountered by the concept of “ biodiversity ”: the issues of defining the units of biodiversity and (...) of choosing a mathematical measure of diversity. I also show that the extension of the scope of biodiversity to microbial entities such as viruses and many other not-clearly-alive entities raises yet another foundational issue: that of defining a “lower-limit” of biodiversity. (shrink)

A distinction between different notions of “structure” and “function” is suggested for interpreting the overwhelming amount of data on microbiome structure and function. Sequence data, biochemical agents, interaction networks, taxonomic communities, and their dynamics can be linked to potential or actual biochemical activities, causal roles, and selected effects, respectively. This conceptual clarification has important methodological consequences for how to interpret existing data and approach open questions in contemporary microbiome research practice. In particular, the field will have to start thinking about (...) notions of function more directly. Also see the video abstract here https://youtu.be/j5pq5uGld1k. (shrink)

Pluralism is popular among philosophers of biology. This essay argues that negative judgments about universal biology, while understandable, are very premature. Familiar life on Earth represents a single example of life and, most importantly, there are empirical as well as theoretical reasons for suspecting that it may be unrepresentative. Scientifically compelling generalizations about the unity of life must await the discovery of forms of life descended from an alternative origin, the most promising candidate being the discovery of extraterrestrial life. Nonetheless, (...) in the absence of additional examples of life, we are best off exploring the microbial world for promising explanatory concepts, principles, and mechanisms rather than prematurely giving up on universal biology. Unicellular microbes are by far the oldest, metabolically most diverse, and environmentally tolerant form of life on our planet. Yet somewhat ironically, much of our theorizing about life still implicitly privileges complex multicellular eukaryotes, which are now understood to be highly specialized, fragile latecomers to Earth. The problem with pursuing a pluralist approach to understanding life is that it is likely to blind us to the significance of just those entities and causal processes most likely to shed light on the underlying nature of life. (shrink)

The human intestinal ecosystem, previously called the gut microflora is now known as the Human Gut Microbiota. Microbiome research has emphasized the potential role of this ecosystem in human homeostasis, offering unexpected opportunities in therapeutics, far beyond digestive diseases. It has also highlighted ethical, social and commercial concerns related to the gut microbiota. As diet factors are accepted to be the major regulator of the gut microbiota, the modulation of its composition, either by antibiotics or by food intake, should be (...) regarded as a fascinating tool for improving the human health. Scientists, the food industry, consumers and policymakers alike are involved in this new field of nutrition. Defining how knowledge about the HGM is being translated into public perception has never been addressed before. This raises the question of metaphors associated with the HGM, and how they could be used to improve public understanding, and to influence individual decision-making on healthcare policy. This article suggests that a meeting of stakeholders from the social sciences, basic research and the food industry, taking an epistemological approach to the HGM, is needed to foster close, innovative partnerships that will help shape public perception and enable novel behavioural interventions that would benefit public health. (shrink)

In this chapter, I am concerned with the concept of Intra-individual Genetic Hetereogeneity (IGH) and its potential influence on biodiversity estimates. Definitions of biological individuality are often indirectly dependent on genetic sampling -and vice versa. Genetic sampling typically focuses on a particular locus or set of loci, found in the the mitochondrial, chloroplast or nuclear genome. If ecological function or evolutionary individuality can be defined on the level of multiple divergent genomes, as I shall argue is the case in IGH, (...) our current genetic sampling strategies and analytic approaches may miss out on relevant biodiversity. Now that more and more examples of IGH are available, it is becoming possible to investigate the positive and negative effects of IGH on the functioning and evolution of multicellular individuals more systematically. I consider some examples and argue that studying diversity through the lens of IGH facilitates thinking not in terms of units, but in terms of interactions between biological entities. This, in turn, enables a fresh take on the ecological and evolutionary significance of biological diversity. (shrink)