Is humanity degenerating?

According to scientists regarding the fact that humanity is degenerating, there really is cause for concern. And this reason - the so-called weak mutations, each of which has little effect on the life and health of an individual, but when they accumulate a lot - the effect is quite palpable.

©Depositphotos
It must be said that everyone has weak mutations. Each child carries in its genome, probably, about ten such mutations that his parents did not have. Therefore, it is clear that if some kind of natural selection was not at all (this can, of course, only be imagined, since it always exists in life), then this species would simply become unviable soon enough.

Imagine, for example, that we are trying to save one such endangered species and we have only a male and female left. After they have a progeny (we will admit that in each generation we can for some reason only get two individuals - a male and a female), we will cross them among themselves. Discarding for simplicity the problem of inbreeding (crossing closely related forms within a single population of organisms), we get another generation - new males and females. Cross again, again we get one male and one female. After many generations, the number of accumulated mutations will become very high, the next offspring will be extremely weakened and unviable (recall the results of the closely related marriages of the royal dynasties - NS). As a result, the population will simply die out.

King of Spain Charles II (Obsessed) because of bad heredity was extremely painful / ©Depositphotos

Without selection, any species must quickly degenerate and die. Simply because: 1) mutagenesis can not be stopped; 2) the majority of non-neutral mutations are harmful.

This shows experiments. One of them was conducted in 1997 by evolutionary biologists on the Drosophila fly. The researchers acted like a scheme described above: in a random order, one female and one male from each generation were taken and crossed. After 30 generations, the experimenters' flies came to a miserable state - their fertility and life expectancy decreased drastically. In addition, they became listless and "did not even buzz".

Fly-Drosophila / ©Depositphotos

There is reason to believe that for the past 100 years people (at least residents of developed countries) have found themselves in conditions reminiscent of this experiment. Thanks to the development of medicine, the invention of antibiotics, the solution of the food problem and the growth of the standard of living, the mortality rate (and, later, the birth rate) fell sharply.

Weak health ceased to be a real obstacle to the continuation of the genus. Moreover, natural selection today generally has little effect on humans, at least if it comes to developed countries. So the danger of accumulation of harmful mutations in the human population is indeed evident. But what is the magnitude of the disaster?

For accurate estimates of data is not enough, but we still have some reasons for restrained optimism. And the thing is that modern data testify: the influence of the genotype in modern people still remains. Even if our character, happiness in family life and political views, of course, are not absolute, but clearly correlate with heredity, what can we say about reproductive success. A man whose genotype has accumulated a lot of faint mutations, on average, is weaker, more sickly, stupid and ugly than many of his contemporaries. No matter how terrible it may sound, it's true. Such a child, among other things, literally costs more than his parents, and therefore they will think hard before giving birth to the second. Let, thanks to the achievements of medicine, our weak and unhappy man survive and leave offspring - this is still not enough that the selection does not work. Selection will cease to be effective only if such a person on average leaves exactly the same amount - up to a fraction of a percent! - children, how much and healthy, strong, intelligent, beautiful, symmetrical, delivered to parents only joy (so they wanted to give birth to one more). Let it be only a fraction of a percent, but the reproductive success of such people burdened with genetic load, even in the most advanced countries, will still be lower than for carriers of fewer weaker-than-normal mutations. The selection did not stop, it only became weaker, but it did not disappear and will never disappear, as long as we live in our biological bodies, and not become robots.

©Depositphotos
So, everyone knows (and scientists are even more so) that the reproductive success of both men and women in the modern world clearly depends on external attractiveness. This example is not only a vital observation, but also a lot of scientific research.

There is also selection at the embryonic level: a fertilized cell overloaded with harmful mutations, as a rule, is "rejected" even in the early stages of pregnancy, as a result of which a woman may have a miscarriage. True, this, of course, is not enough to save mankind from degeneration, since the same processes were observed in Drosophila - and, nevertheless, they did not save the flies participating in the experiment from their sad future.

It remains to pin great hopes on the technology of in vitro fertilization (IVF) - the conception of in vitro, which involves the creation of several "spare" zygotes (fertilized eggs) that grow to one of the earliest stages of development, and then the most healthy ones for transplantation into the body are selected from them future mother.

In fact, natural selection has actually become weaker. However, today, perhaps, we do not need a strong one. After all, the number of mankind for today is incredibly high - more than seven billion. Such a number can not boast of any kind of terrestrial vertebrates of our size in the history of the planet Earth. Meanwhile, the population size has the most direct relation to the effectiveness of the selection action on the weak mutations: the larger the population, the less chance of a weak mutation to spread in the gene pool.

In addition, the huge size of the population gives mankind a chance and the fact that in our gene pool there will be rare useful mutations, which, perhaps, will help the best adaptation of the whole species. Despite the development of medicine, no one canceled the special selectivity of individual citizens with regard to the choice of a sexual partner. I personally really hope for the princesses. If only they did not become illegible in connections. Dear Princesses! Remember, please, that when choosing a life partner, political correctness is inappropriate. You deserve more. Carefully follow the fitness indicators. Do not confuse genuine big, beautiful and expensive peacock tails with cheap fakes. "

Relatively speaking, very beautiful and successful ladies, as a rule, tend to choose exactly such gentlemen, and vice versa - ugly, poorly educated and unsuccessful marry losers and their whole life endure (this principle exists in nature).

Not always the mortality rate, moreover, correlates with the effectiveness of natural selection. Thus, children died of smallpox in the Middle Ages did not necessarily all have been weak, as well as those who died as a result of numerous wars and famine - they may have simply been unlucky. Today, in general, people become richer, many achieve the achievements of modern medicine, so this "leveling" can help to ensure that natural selection will be more responsive to genes, of course, the "best" individuals.