2023-05-10 20:33:07
Dhen modern man, tens of thousands of years ago, when half the world was still being shaken by ice ages, sometimes sought a liaison with the coarser-looking but soon to be extinct Neanderthals, apparently worked to his advantage. The nose is perhaps an example of this. Many of today’s South Americans and also a number of Asians carry gene segments in their genome that shape the shape and size of the nose and are said to clearly come from Neanderthals.
ATF3 – which stands for “Activating Transcription Factor 3” – is the corresponding gene on chromosome one. It is extremely important evolutionarily. On the one hand, it has been proven to regulate the regeneration of nerve tissue after a serious injury. On the other hand, during the development of the fetus, it also indirectly controls the shape of those parts of the middle region of the skull that will later form the base of the nose. What’s more, this bone region also determines how big the nose will be in the end and how it is shaped. Their genetic makeup is similar in Homo sapiens and other prehistoric humans, but by no means the same.
The different nose heights in modern humans (left) and Neanderthals.
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Image: Dr Kaustubh Adhikari, UCL
Ironically, the gene sequence present in Neanderthals – and thus the corresponding construction instructions – has now been discovered in many representatives of Homo sapiens. A British research group at University College London has this in the current issue of the journal „Conservation Biology“ reported. The aim of the scientists was to identify the genes that are crucial for facial formation. In their project, they subjected almost six thousand predominantly South Americans of different origins to a genetic analysis. Using various portrait photos and after meticulously measuring the parts of the face, they compared the key facial features with the occurrence of gene variants that could be relevant to facial development. The result was 42 face-shaping genes, 33 of which were previously unknown.
One molecular feature – ATF3 – then caught the attention of scientists. Because the ATF3 variant found in a large number of subjects, who also had a high nasal base typical of Neanderthals and at the same time a larger nasal base, were also equipped with the Neandertal version of the ATF3 gene. The fact that the nose of the South Americans in question is not nearly as massive also shows that ATF3 is by no means the only form-forming hereditary trait.
Advantages of moving out of Africa?
But what should the Neanderthal residues in the nose gene be good for? As a review of other gene databases by the British research team revealed, the Neanderthal gene sequences of ATF3 are also distributed in Asia, but hardly (still?) in Europe. How this unequal distribution came about is a mystery. It is at least clear to the scientists that there must be a reason for the preservation of the Neanderthal variant. Their argument: Since the inheritance of this particular variant has persisted in millions upon millions of people and through thousands of generations, the Neanderthal heritage should have provided an advantage, according to the researchers, at least for a while. Exactly what that was, one can only speculate.
The British genetic researchers believe, however, that it has to do with the climate that prevailed when Homo sapiens migrated north from Africa. It is possible that a larger nose brought functional advantages with changing temperatures and humidity – under harsh environmental conditions. Form, design and therewith the size of the nose has long been discussed as a body trait associated with different climates. A similar climate-relevant gene, which the researchers found earlier in modern humans, albeit in a variant that belongs to the long-extinct eastern Denisovans, ensures greater storage of fat in the body. In addition, however, it also contributes to the formation of plumper lips. The faces of many of today’s people are therefore definitely the product of the prehistoric mixed “marriages” of different human ancestors.
#nose #jewelry #precious #heirloom