Neanderthal neurograstronomy

There is a genetic basis to the food that we enjoy eating. Some people – which I call strange people – think cilantro has a strange, soapy taste at least partially because of a particular polymorphism in a odor receptor gene (OR6A2).

soapy cilantro

The question of why we enjoy certain foods and flavors is not solely a genetic one, but also a conceptual one. Take the questions of why we like spicy food. Other animals do not: they will eat spicy food but would rather prefer not to, thanks. If you ask people what the best spiciness level is, they will tell you that it is whatever is right below their pain threshold. A smidgen too much and it is unbearably hot. A smidgen too little and it is bland as they come. The molecule that gives something its spiciness is capsaicin which stimulates the same receptors that give information about the warmth of food. It is possible, then, that this is a byproduct of our adaptation to prefer cooked food. Food that has been roasted is digested more quickly and provides more calories.

But knowledge of genetics can give us insight into those we do not have direct experience with. We now have genomic sequence data from one Denisovan and two Neanderthals. Do they experience food similarly to modern humans?

In many ways, yes. One change that probably occurred after the invention of cooking is a reduction in certain masticatory muscles. Once you can cook, your needs to chew really really hard are reduced. And a gene responsible for this, MYH16, is expressed in chimpanzess (no fire) but not in humans (plenty of fire). It turns out that MYH16 is also not expressed in the Denisovan and Neanderthal samples.

We can also look at a taste receptor, such as TAS2R38 which responds to phenylthiocarbamide (PTC). This is a flavor that, depending on your genetic makeup you either cannot taste at all, or that tastes very bitter. There is variation across populations: 98% of people indigenous to the Americas can taste it while only 42% of those indigenous to Australia and New Guinea cannot. Interestingly, chimpanzees can also taste it but they do so in a different manner.

None of the Denisovan or Neanderthals had the human mutation that allowed PTC-tasting. But that shouldn’t stop them from tasting it: one of the Neanderthals had a different mutation from either humans or chimpanzees on the gene. This is convergent evolution at work, people.

Even more interestingly, the AMY1 is a gene responsible for the enzyme that starts the digestion of starch. Starch is responsible for something like 70% of the calories in human agricultural population. The more copies we have of this gene, the more of the enzyme we have in our saliva. Chimpanzees have two copies: humans have around 6 or 7 of them. And these Denisovans and Neanderthals? Only two!

You are what you eat, and what you eat is influenced by what you are. It’s pretty fun that we can get at what a Neanderthal enjoyed eating by looking at the genetics of their taste receptors…

References

Perry, G., Kistler, L., Kelaita, M., & Sams, A. (2015). Insights into hominin phenotypic and dietary evolution from ancient DNA sequence data Journal of Human Evolution DOI: 10.1016/j.jhevol.2014.10.018

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