Jul 16, 2023 03:35 PM
https://iai.tv/articles/rob-dunn-the-mic..._auid=2020
EXCERPTS (Rob Dunn): . . . one could easily argue, for example, that fungi have domesticated leaf-cutter ants as demonstrated by the extent to which they have altered the behaviour, diet, reproduction and even the shape and size of the ants. One could also argue, as I do here, that yeasts have domesticated humans.
[...] We now know that at some point around ten million years ago – about the time of the common ancestor of orangutans, gorillas, chimpanzees and humans – apes entered into a new relationship with yeasts. The relationship was sufficiently transformative so as to alter the genomes of every ape to have lived since, including every human.
It is thought that apes first encountered yeasts in rotten fruits. When fruits rot, they can become covered in filamentous fungi (AKA, mold), which is often unsafe to ingest. They can become colonized by lactic acid bacteria – like those found in yogurt – in which case they become acidic and safe to eat (think sauerkraut). Or they can become colonized by yeasts and become alcoholic. In practice, many tropical fruits are probably a mixture of lactic and alcoholic, like sour beer.
The drunken monkey hypothesis suggests that as apes spent more time on the forest floor (having become too big to move as readily among the trees as had their ancestors) that they began to eat more rotten fruit (Dudley 2014). The evolutionary evidence for this change is threefold. Roughly ten million years ago, apes evolved a version of the alcohol dehydrogenase gene capable of metabolizing alcohol forty times faster than the previous version.
The version of the gene allowed apes to get many more calories from alcohol than they might otherwise; this change, along with others we don’t yet fully understand, may have also made them more likely to get buzzed and hence to feel rewarded for their choice (Carrigan et al. 2015).
In addition, recent research by Claudia Staubert and colleagues has shown that at about the same time (give or take a few million years) apes also evolved new receptors for lactic acid, like that found in fermented fruits. Those receptors, when stimulated, trigger ape bodies to stop burning fat and also send signals to the immune system to calm down.
Both responses would benefit apes that were eating rotten fruit in that they would tell the body “stop burning fat, we’ve got sugar,” and “woah, the bacteria in this food aren’t dangerous (Peters et al. 2019).” Finally, recent research on which I collaborated has shown that at some point apes also evolved a preference for sour foods (Frank et al. 2022).
Here are hints of an interesting possibility, namely that yeasts and lactic acid bacteria were beginning to domesticate apes. They were starting to trigger changes in ape biology that would make the apes more likely to ingest fermented foods and thus carry the yeasts to new places, including new fruits. In short, they were triggering changes in ape biology that made the apes more like wasps... (MORE - missing details)
EXCERPTS (Rob Dunn): . . . one could easily argue, for example, that fungi have domesticated leaf-cutter ants as demonstrated by the extent to which they have altered the behaviour, diet, reproduction and even the shape and size of the ants. One could also argue, as I do here, that yeasts have domesticated humans.
[...] We now know that at some point around ten million years ago – about the time of the common ancestor of orangutans, gorillas, chimpanzees and humans – apes entered into a new relationship with yeasts. The relationship was sufficiently transformative so as to alter the genomes of every ape to have lived since, including every human.
It is thought that apes first encountered yeasts in rotten fruits. When fruits rot, they can become covered in filamentous fungi (AKA, mold), which is often unsafe to ingest. They can become colonized by lactic acid bacteria – like those found in yogurt – in which case they become acidic and safe to eat (think sauerkraut). Or they can become colonized by yeasts and become alcoholic. In practice, many tropical fruits are probably a mixture of lactic and alcoholic, like sour beer.
The drunken monkey hypothesis suggests that as apes spent more time on the forest floor (having become too big to move as readily among the trees as had their ancestors) that they began to eat more rotten fruit (Dudley 2014). The evolutionary evidence for this change is threefold. Roughly ten million years ago, apes evolved a version of the alcohol dehydrogenase gene capable of metabolizing alcohol forty times faster than the previous version.
The version of the gene allowed apes to get many more calories from alcohol than they might otherwise; this change, along with others we don’t yet fully understand, may have also made them more likely to get buzzed and hence to feel rewarded for their choice (Carrigan et al. 2015).
In addition, recent research by Claudia Staubert and colleagues has shown that at about the same time (give or take a few million years) apes also evolved new receptors for lactic acid, like that found in fermented fruits. Those receptors, when stimulated, trigger ape bodies to stop burning fat and also send signals to the immune system to calm down.
Both responses would benefit apes that were eating rotten fruit in that they would tell the body “stop burning fat, we’ve got sugar,” and “woah, the bacteria in this food aren’t dangerous (Peters et al. 2019).” Finally, recent research on which I collaborated has shown that at some point apes also evolved a preference for sour foods (Frank et al. 2022).
Here are hints of an interesting possibility, namely that yeasts and lactic acid bacteria were beginning to domesticate apes. They were starting to trigger changes in ape biology that would make the apes more likely to ingest fermented foods and thus carry the yeasts to new places, including new fruits. In short, they were triggering changes in ape biology that made the apes more like wasps... (MORE - missing details)