If you have ever taken a look at the biological classification, you probably have noticed that there are many species that encompass subspecies . For example. There are two types of elephants; Africans and Asians. Another good example of this variety of subspecies within the same animal species is the genus Canis . The Canis includes all species of dogs , from the wolf to the fox, including the jackal. Then it is correct to think that all species are part of a larger group of gender. However, what happens with the human being? Why is there only a single human species?
Actually there was a time when the human being was divided into several species, they even cohabited. It is the case of Neanderthals and Denisovans that even had offspring.
When man was not a single human species
Surely you have heard of more than one occasion Homo neanderthalensis , known as Neanderthal, you may even have a slight idea of what it looked like. But have you ever heard of the mutual cousin of Homo Sapiens and Neanderthals? Denisova's hominid
In 2018, in the Altai mountains of Siberia, a group of paleoanthropologists who were searching for the Denisova cave, came across some fascinating remains; the tooth of an adult and the pinky of a child, both 40,000 years old.
For two years they were analyzing these remains, until finally two years later they managed to decipher the mitochondrial DNA of the little finger bone. It must be borne in mind that mitochondrial DNA can only be transmitted by the mother and this suggested that the bone belonged to a girl of about 5 or 7 years who was Neanderthal by only 50%. Maybe the other percentage belonged to a Denisovan.
There is a great debate about whether Denisovans are a more human species or , Conversely, they are a subspecies of Neanderthal but they were different enough for paleoanthropologists to consider investigating these differences.
In 2016, Samantha Brown, of the Oxford University , published the results that she had obtained in a genetic study that she had carried out in a fragment of bone found in the denisova cave. According to this analysis, the fragment investigated belonged to a 13-year-old girl whose mother was Neanderthal, based on the result of mitochondrial DNA.
In addition, with this study, they could also access nuclear DNA that is inherited from both parents. Access to this DNA allows researchers to also know the genetic information of the father.
It was not until 2018, when Viviane Slon, of the Max Planck Institute for Evolutionary Anthropology, discovered that this 13-year-old prehistoric teenager had Neanderthal and Denisovan DNA. As it was discovered at first, with the mitochondrial DNA, that his mother was Neanderthal, so his father had to be a Denisova hominid.
Human hybrids
Actually this hypothesis is not new. The idea has existed for a long time that there was not a single human species and that they also crossed each other. But this latest discovery sheds new light on this mystery. The fact of having found hybrid DNA in such a small sample suggests that miscegenation was very common during this era, the Pleistocene.
Surely the Neanderthals were not the only human species that mixed with the Denisovans , since we can assure that Denisova's hominid DNA survives to this day, specifically in the region of Melanesia, on the Pacific island .
Between 4% and 6% of the DNA of Melanesia we can link it to the Denisovans. Just as the Europeans show signs of Neanderthal, the Melanesians do not, suggesting that the Denisova hominids could mix, in this case, with other species such as Homo Sapiens.
Up to this point, we have already told you about three different species of the same genus; the homo. Each of these three species were strong enough to keep their genes alive today, but the reality is that there were not only these three species. Actually there were many more prehistoric humans and what we have not yet discovered is why some survived and others did not.
Patrick Roberts of the Max Planck Institute for the Science of Human History and Brian Stewart of the University of Michigan have a new theory. What caused some species to evolve and others did not have anything to do either with having a greater brain, or with the ability of language even with technological developments. If we had this in mind, any of the species had something to contribute; Many of them developed fire, Homo Sapiens managed to leave Africa, Neanderthals in Europe used cutting-edge technology such as aspirin and had developed the art of painting.
So, why is the human being of today, as the only human species, able to survive and survive the DNA of other species?
The answer is generalization. Researchers know that the current human being is a "generalist specialist" that is, they can assume any possible role. Some of our distant cousins were able to survive in extreme climates, so we were able to find a way to, if not survive, adapt. With that adaptation, we mixed with the local population and we took their DNA in our future generations.
What did you think of the article? As we explained at the beginning, do you think that the human being has always been a single human species divided into subspecies, or were different species within the same genus? Give us your hypothesis, we will be happy to read them.