Who selected who?

 

Friday Race

One of the days the garbage truck comes by is Thursday, so early in the morning I swept up my dogs' poop to put in the trash. This Thursday, while I was doing it, I asked myself a question.

I think that's why in this race my wondering began with the relationship between dogs and humans. This relationship began about 15 thousand years ago, although some say it could be up to 30 thousand years ago. Apparently it started with little gray wolves (Canis lupus) that approached the surroundings of the human camps to feed on the waste. I say small since large wolves were dangerous and would have scared away humans.

Another interesting characteristic of these small wolves is that they had to be able to digest plant remains, since our waste contained not only meat. So these little wolves had to be able to digest starches, which is not something wolves do. Probably among the changes that allowed them to use starches were smaller size and docility.

Now, every relationship goes in two directions, among humans there must have been some who were not afraid of wolves, which are dangerous animals, so they approached these little wolves and lived with them. With this an interesting relationship began, the little wolves, now we call them dogs, had food and protection, the humans a faithful animal that took care of the camp and a good helper for hunting. But also, both species gained company that they greatly enjoyed.

This is how the first domestication appeared, curiously of a species that we did not use for food.

A few years ago the “Paleolithic Diet” was popular. The proponents of this diet said that we had to eat the foods that humans consumed in the Paleolithic, before agriculture, since the vegetables we grew were not part of our diet. 

I always made two criticisms; First, Paleolithic foods from what region? Humans consumed what was in each region, which was very different from one place to another. Second, if we grew something, it was undoubtedly part of our diet, domestication was not done “in a snap”, we knew the species we domesticated very well, they were ones that we used most intensively. 

Based on the knowledge we had of the species we used, we began to see how to take advantage of them in such a way that we ended up controlling their life cycles. This was related to another interesting thing, we were selecting the characteristics that best suited us in these species, a new type of selection appeared, no longer natural selection, an artificial, anthropogenic selection. So after several generations, domesticated organisms are totally different from their wild ancestors. Humans have made a selection of the genetic characteristics that suit us, which is why all domesticated species have been genetically modified, all of them.

But we must understand that domestication goes in both directions, in each region of the planet humans domesticated different species, so there was also selection for humans. The best example is what happened with human communities that domesticated cattle, in Europe and Southern Africa, independently. Obviously these humans now had a new food at their disposal, milk, rich in many things, including lactose. But it turns out that in humans only infants produce the enzyme to process lactose, lactase, when we stop consuming breast milk we stop producing that enzyme. So all humans should be lactose intolerant. Only very few people must have continued to produce lactase, these were selected by cattle in Europe and Southern Africa.

This happened everywhere, humans were selected based on the foods we consumed most frequently, those we had domesticated.

Many of the health problems currently experienced are related to this. With globalization, many foods are consumed in regions where humans are not adapted to them. For example, it is very clear that different communities are more susceptible to diabetes by consuming carbohydrates for which they were not selected.

One detail, we not only domesticate plants and animals, but also fungi and microorganisms. Think about the manufacturing of bread, antibiotics, or…

Let me think, I think I'll have to go for a beer to remember.

Ah, the question I asked myself yesterday while sweeping up my dogs' poop. In this relationship, who is the master of whom?