Tag Archives: pathogen

Bigger is Better

Population size impacts host-pathogen coevolution (2021) Papkou et al. 2021, Proc B, https://doi.org/10.1098/rspb.2021.2269

Image credit: Kbradnam, CC BY-SA 2.5, via Wikimedia Commons

The Crux

Host-pathogen interactions are maybe best characterized as a battle – a pathogen (a parasite that causes disease) doing what it can to maximize how much it can get from a given host organism, and a host doing what it can to defend itself from this endless attack. As a result, hosts and pathogens are locked in an endless evolutionary battle, whereby hosts evolve to better defend themselves and pathogens evolve to better attack the host. A key factor in this battle is population size, as this affects the evolutionary potential of a given population of organisms to respond to selection.

The larger a population of hosts, the more novel genetic variants there are, which are simply organisms with different genetic make-ups, which can be the result of mutations popping up or through combinations with other genetic variants within the population. The more variation there is, the more diverse the population is, and the more chance it has of carrying the genes that could help it respond to a new threat, like a pathogen.

This means that a larger host population is more likely to have a genetic variant that is able to defend itself from these pathogens. That variant will then be selected for and the host population will become more resistant to that pathogen over time. While a lot of theory has been dedicated to understanding these coevolutionary battles, actual experimental evidence is lacking. Today’s authors used a model system to conduct evolutionary experiments to test the effect of host population size on host-pathogen coevolution.

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An Ugly Truth: Pandemics and the Livestock Trade

Image Credit: Hippopx, CC0 1.0, Image Cropped.

Ever since COVID-19 hit, things have changed for people the world over. Many governments enforced lockdowns on their citizens, certain products are harder to get than before (looking at you toilet paper hoarders), and there has been an enormous and terrible loss of life. A wet market in China is suspected to be the source of the outbreak, but one thing to consider as we move forward is that the risk of another outbreak from other animal markets remains high.

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What the Hell is On My Plant: A Botanist’s Guide to Metagenomics

Image Credit: Mislav Marohnić, CC BY 2.0, Image Cropped

If you’re unlucky, you already know that humans possess a skin microbiome. It sounds gross, but it’s simply an entire ecosystem of  microbes like bacteria living on our skin (maybe it is gross). Some of them help us, others might make us sick, for example when they enter open wounds. Plants have a similar set-up, hosting different ecosystems of bacteria on their leaves.

Hopefully, at this point I’ve made your skin crawl (because as you now know, it is literally crawling). But that microbiome can actually tell us some fascinating things about the animal or plant we’re looking at. So today, I’ll go through exactly what metagenomics is, and some of the information we can glean from a plant’s surface (I am a botanist after all).

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