Scientists claim that globalization, immigration, cultural diffusion and the facilitated locomotion of the modern world must gradually homogenize the human population. Recessive traits, which depend on two copies of the same gene, are destined to go extinct. As for the dominant traits, these should become the norm. And the end result? Perhaps, a people very similar to the Brazilians of today. Understand why:

shortening distances

It is increasingly difficult to find human settlements with unique characteristics. Between the 1800s and 1960s, for example, the isolated population that lived in the hills of the US state of Kentucky stood out from the others by a somewhat unusual characteristic: the blue skin. Result of six generations of inbreeding (relationships between close relatives), all descendants of French martin fugate suffered from the same rare blood condition called methemoglobinemia. In it, a recessive gene pairs up and changes the molecular composition of the blood, generating a brown color instead of the traditional red. This change shows up on the skin in the form of a bluish tinge:

Hematologists' attempt to trace the family's mutant gene history fugate, as well as its preservation, confirmed the village's tradition of marrying off first cousins, uncles and nephews, and so on, through the generations. Dennis Stacy, family member whose great-grandparents on both sides are the same person, Henley Fugate, explains it simply: “In the old days, in eastern Kentucky, there were no roads. "

the family tale fugate it is a miniature version of the history of human unions since time immemorial. Local populations relate to each other, ensuring an exchange of genes that results in a group with physical similarities that ultimately identifies itself as a distinct race or ethnic group.

According to a Stephen Stearns, professor of ecology and evolutionary biology at Yale University, before the invention of the bicycle, the average distance between spouses' birthplaces in England averaged 1,6 km. During the last half of the 19th century, this distance reached an average of 48 km. With the advent of automobiles and airplanes in the following decades, the horizons of love kept expanding ever since.

"The distance between parents' birthplaces has continued to increase since the invention of the bicycle, making it easier now, if not the new rule, for parents to have been born on different continents," he said. Stearns.

As a result, traits generated by recessive genes, which must be passed on from both parents to manifest in their offspring, must gradually disappear.

Recessive genes tend to disappear

In the United States, for example, blue eyes have grown much less than brown eyes. A 2002 study by epidemiologists Mark Grant e Diane Lauderdale, found that only 1 in 6 white (non-Hispanic) Americans had blue eyes at that time. Just 100 years ago, more than half of the American population had blue eyes.

“The only explanation for the observed pattern that was consistent with the data presented was the breakdown of the preferential mating pattern,” he says. Diane. For those who don't know, this is the tendency of people to marry members of their same ancestral group, something that, apparently, has diminished over time.

Diane Lauderdale says blue eyes shouldn't die completely; they will simply settle to a low level, which reflects the chance of mating between two individuals who have recessive genes that result in blue eyes.

The miscegenation resulting from the ease of locomotion of the modern world should reduce other recessive traits characteristic of European and North American peoples, such as fair skin, blond and red hair, or freckles. The evolutionary biologist john mcdonald, from the American University of Delaware, states that it is not easy to predict how the mixture of genes affects physical appearance (it depends on the combination of several factors and genes), but the tendency is for dominant traits to remain. With this, fair skins should give way to darker tones, as well as hair coloring.

And we Brazilians, where do we get into this?

The genetic mixing taking place in the United States is also happening to a greater or lesser degree in other parts of the world, the researchers said. Even so, there are still places where migratory processes are less expressive, or with peoples that have unique physical characteristics adapted to the habitat – which confer evolutionary advantages to their owners – and which end up slowing down global miscegenation.

To Stearns, the perfect homogenization of the human race will probably never occur, but it is a fact that the inhabitants of Earth are getting closer and closer to a biotype with similar traits. The varied population, forged from the long-term mix of Africans, Americans and Europeans serves as an archetype for the future of humanity. He ends by saying: “A few centuries from now, we will all be like Brazilians”.

Source: LiveScience, scribol, sickchirpse, Wikipedia.