Oct 4, 2018 10:56 PM
https://aeon.co/ideas/i-holobiont-are-yo...gle-entity
EXCERPT: . . . These organisms together make up what’s known as a holobiont: a combination of a host, plus all of the resident microbes that live in it and on it. The concept has taken off within biology in the past 10 years [...] Some of the microorganisms kill each other with toxins, while others leak or release enzymes and nutrients to the benefit of their neighbours. As they compete for space and food, cohabiting microbes have been found to affect the nutrition, development, immune system and behaviour of their hosts. The hosts, for their part, can often manipulate their resident microbiota in many ways, usually via the immune system.
You yourself are swarming with bacteria, archaea, protists and viruses, and might even be carrying larger organisms such as worms and fungi as well. So are you a holobiont, or are you just part of one? Are you a multispecies entity, made up of some human bits and some microbial bits – or are you just the human bits, with an admittedly fuzzy boundary between yourself and your tiny companions? The future direction of medical science could very well hinge on the answer.
[...] The ecological and evolutionary views make for very different predictions about how a holobiont will change over time. Evolutionary theory predicts that the parts of a unit of selection will tend to cooperate: to sacrifice their own interests for the good of the whole. Ecological theory, by contrast, predicts competition and exploitation: parts will cooperate only insofar as it benefits them. Think of the differences between an ant colony and a motley assortment of insects fighting over scarce resources.
A dominant view in medicine treats the body as a battleground where any invaders are bad and must be exterminated. But in an ecosystem, there are no bad guys, just species playing different roles. If the ecological account of holobionts is true, a human host is more like a habitat to be managed, with the right balance and competition between different kinds of microbes being an important consideration. [...]
However, the evolutionary version of holobionts gives us reason to stick to an expanded version of the ‘us versus them’ picture of medicine. It’s just that now we have a few more allies on our side that we need to take care of. The evolutionary framework might also provide some justification for the calls for a return to a palaeomicrobiome that existed before the modern diet – for that would literally help to return a missing part of ourselves.
As things stand, the evidence leans heavily towards a more ecological interpretation of holobionts. Most of the partners come together anew each generation, and don’t interact in the ways that are necessary for higher-level integration into organismic wholes. [...] But it potentially varies from holobiont to holobiont. There is still a long and exciting scientific road ahead [...]
MORE: https://aeon.co/ideas/i-holobiont-are-yo...gle-entity
EXCERPT: . . . These organisms together make up what’s known as a holobiont: a combination of a host, plus all of the resident microbes that live in it and on it. The concept has taken off within biology in the past 10 years [...] Some of the microorganisms kill each other with toxins, while others leak or release enzymes and nutrients to the benefit of their neighbours. As they compete for space and food, cohabiting microbes have been found to affect the nutrition, development, immune system and behaviour of their hosts. The hosts, for their part, can often manipulate their resident microbiota in many ways, usually via the immune system.
You yourself are swarming with bacteria, archaea, protists and viruses, and might even be carrying larger organisms such as worms and fungi as well. So are you a holobiont, or are you just part of one? Are you a multispecies entity, made up of some human bits and some microbial bits – or are you just the human bits, with an admittedly fuzzy boundary between yourself and your tiny companions? The future direction of medical science could very well hinge on the answer.
[...] The ecological and evolutionary views make for very different predictions about how a holobiont will change over time. Evolutionary theory predicts that the parts of a unit of selection will tend to cooperate: to sacrifice their own interests for the good of the whole. Ecological theory, by contrast, predicts competition and exploitation: parts will cooperate only insofar as it benefits them. Think of the differences between an ant colony and a motley assortment of insects fighting over scarce resources.
A dominant view in medicine treats the body as a battleground where any invaders are bad and must be exterminated. But in an ecosystem, there are no bad guys, just species playing different roles. If the ecological account of holobionts is true, a human host is more like a habitat to be managed, with the right balance and competition between different kinds of microbes being an important consideration. [...]
However, the evolutionary version of holobionts gives us reason to stick to an expanded version of the ‘us versus them’ picture of medicine. It’s just that now we have a few more allies on our side that we need to take care of. The evolutionary framework might also provide some justification for the calls for a return to a palaeomicrobiome that existed before the modern diet – for that would literally help to return a missing part of ourselves.
As things stand, the evidence leans heavily towards a more ecological interpretation of holobionts. Most of the partners come together anew each generation, and don’t interact in the ways that are necessary for higher-level integration into organismic wholes. [...] But it potentially varies from holobiont to holobiont. There is still a long and exciting scientific road ahead [...]
MORE: https://aeon.co/ideas/i-holobiont-are-yo...gle-entity
