Is the more human evolution, the lighter the skin color? Is skin color related to intelligence?

In fact, molecular biology is really a savior. After it appeared, we found that the evolutionary route of human beings was completely different from what most people imagined and obsessed with, which destroyed all racist theories. The first amazing discovery is that all human beings are Homo sapiens from Africa, not Homo sapiens animals evolved from their own land. The second person's amazing discovery is that the genetic diversity of human beings is surprisingly low, and the genetic diversity of 7 billion human beings is even worse than that of a chimpanzee family in the Congo jungle.

▲ If you look closely, you will find that the appearance of Africans is very different.

The reason why genetic diversity is so low is that human history is too short. According to the current research results, Homo sapiens has not appeared for more than 350,000 years. Compared with the history of other species, it is like a newborn baby (annoying mosquitoes appeared 65.438+0.7 billion years ago, and they were all found in amber in the dinosaur era). All the ape-man fossils found in China, including Peking Man and Homo erectus belonging to Yuanmou Man, have lived on this continent for more than 6.5438+0 million years, making them the longest-lived ape-like animals in history.

Another reason why the genetic diversity of Homo sapiens is so low is that Homo sapiens leaving Africa is a very small group, only about 65438+100000. Although Africa's population now accounts for only 17% of the world's total population, the other 5.8 billion human beings are descendants of that 10000, so this has produced a very counterintuitive result-the genetic diversity of human beings in the other five continents is not as much as that in Africa, especially between Europeans and East Asians, and the genetic gap is almost negligible.

Double-line whitening

Homo sapiens rushed out of Africa 70,000 years ago and began to spread to Eurasia after conquering Neanderthals. One of them went north to Europe, and the other changed course halfway north, crossing Siberian snowfields and Mongolia to reach the east coast of Asia. This group spread continuously, and some of them crossed the frozen Bering Strait and entered America, that is, the indigenous people of America-Indians and Mayans, Aztecs and Incas.

The branch of Homo sapiens who stayed in East Asia is the main ethnic group in China, including Han nationality, Japanese race and Korean race. It used to be called "Mongolian", but now we prefer to call it East Asian.

Sunlight can bring vitamin D to the skin. Vitamin D is very important for the development of bones, but too strong sunlight can harm the skin, so African skin is rich in melanin to absorb ultraviolet rays. However, in high latitudes, sunshine is scarce and heavy clothes hinder it, so it is difficult to get enough sunshine. Therefore, for normal growth and development, Europeans and East Asians have evolved whitening methods.

However, in terms of scheme, the two are not the same. The two genes that have the greatest influence on the white skin color of Europeans are SLC24A5 and SLC45A2. Among them, a mutation A11t of SLC24A5 gene will destroy the synthesis of NCKX5 protein, and the mutation of SLC45A2 will destroy the synthesis of MATP protein. These two kinds of protein are closely related to the synthesis of melanin, which means that the gene mutation in Europe destroys the synthesis of melanin.

But East Asians are completely different. The gene that dominates our skin color is OCA2, which participates in the transport of tyrosine (the raw material of melanin synthesis) in melanocytes, and regulates the pH value of melanosome, thus regulating the maturity of melanosome. The more mature the melanosomes are, the darker the skin is, so the melanin of East Asians is an adjustable mechanism.

▲ From left to right are Africans, East Asians and Europeans.

Therefore, in the case of not accepting light at all, our skin color is not particularly different from that of whites, but it is not easy for Europeans to turn black in the sun, because it is really difficult for them to synthesize melanin. In western society, wheat color is considered as the healthiest color, but even so, sunbathing takes a long time. But we East Asians, in the strong sunlight, will easily turn the small knob of genes to the maximum, so it will become darker.

Intelligence is mainly influenced by the degree of civilization.

It can be seen that our skin color has no evolutionary relationship with the skin color of Europeans. Their ancestors evolved light-colored skin through different paths to adapt to the environment. The so-called "evolutionary ladder" research based on skin color is even more a joke. Of course, there is a certain consensus between us. After all, after the country becomes rich and strong, few people will think that China people are inferior to whites.

However, there are not a few people in China who ridicule the African people with their skin color and intelligence. This is actually wrong for two main reasons:

First of all, intelligence is completely trainable, and the level of education will significantly change the score of intelligence test.

Secondly, there are many factors that affect the development of human social civilization. Subjectively, the more developed the civilization, the more obvious the so-called "high intelligence" performance, and the speed of civilization development is greatly influenced by the geographical environment.