I know, the title of my column is worthy of a science fiction novel, but it is still too early to turn the page and close the chapter of this planetary fight of which we are all a part. So let’s focus a little more on science than fiction.
In my previous column, I spoke about microbial time and this French study which had shown that in terms of the number of generations produced, one year in the life of the bacterium Escherichia coli is equivalent to nearly 84,000 human years. However, 84,000 years ago, there were other species of humans that lived on the planet. Yep, Sapiens had roommates in his Terran bungalow.
Allow me in this text to take the comparison a little further and tell how the story of the Sapiens variant may resemble that of Omicron, which has just arrived.
Like Omicron, humans are mutants, a variant of the Homo genus that has become Sapiens, “learned or wise”, thanks to a cognitive revolution. The most common attempt at an explanation evokes a climatic episode, a drought that would have pushed our arboreal ancestors to leave the foliage of trees to look for something to eat in open areas. This change in lifestyle would have gradually led to the onset of bipedalism which, in turn, was an anatomical precursor of language development, which is central to our intelligence.
Sapiens is a big-brained mutant standing on both legs, which allows him to see further ahead the prey he wants to hunt and the predators who want to eat him. The bipedalism has also made humans an enduring runner capable of chasing big game until they forfeit. Walking on two legs has also freed our arms, which will become tools of transport and powerful launching pads for projectiles. At arm’s length, Sapiens’ hands transformed into precision tools as effective as a Swiss Army Knife when it came time to build or craft things, including tools and weapons.
In women, bipedalism also caused a narrowing of the pelvis. Forcing her to give birth to one of the most immature babies in the mammalian world. As the head may not pass after this time, it must be forcibly evicted at the end of the nine-month lease.
A human infant is a howling digestive tract of which only 10% of the brain is wired. The advantage of giving birth to this almost virgin hard drive is that it can be programmed in family, community and schools to transfer a lot of knowledge.
It is by assimilating the intelligence of those who came before us that we become knowledgeable. In truth, explaining how Homo became Sapiens is quite complicated and more complex than what I have just summarized for you. It is an enormous interdisciplinary subject which still mobilizes a lot of neurons in the research on our origins.
Going back to my story, let’s just say that when, boosted by this cognitive revolution, Sapiens left Africa about 300,000 years ago, there were at least eight other species of humans on Earth, including Neanderthals, l man of Flores and that of Denisova. However, between 30,000 and 50,000 years ago, the other species of humans finished their bow to leave only Sapiens as the sole winner in the biosphere. The roommates were gone, he now had the planetary bungalow to himself, with thousands of pets, of course. And since he messed up the house, but that’s another story …
The Strongest…
Likewise, where are the variants that gave us the scares long before Omicron? They gave way in front of a stronger one in this musical chair which well describes the evolution of the virus. When a champion arrives, the less competitive mutants end up disappearing or surviving in the population pockets still sheltered from this stronger. Even the variant that emerged in almighty Britain failed to reap the lion’s share of occupying the biosphere. For once, in a race to colonize the planet, England did not have the last word. Even more ironic, the variant, dubbed Alpha, who appeared there was defeated by Delta, who allegedly ironically emerged in the former Indian colony.
What I’m trying to bring here is that this viral substitution process is similar in some ways to what played out during the odyssey of our own species. The meeting between Sapiens and Neanderthals is still of great interest to scientists. She is as passionate as the match currently being played between Delta and Omicron.
Why did this Neanderthal disappear with the arrival of the newcomer who ended up taking all the space? The hypotheses are numerous: the effect of climatic and faunal modifications on the survival of Neanderthals; its democracy in decline because of the dispersion in the territory; a genocide signed Sapiens; his diet less diversified and too meaty, which would have made him more vulnerable to faunal changes, etc. You will find another explanation in the excellent book by anthropologist Joseph Henrich entitled Collective intelligence – The success of Sapiens. The author says that the incredible abilities of the human species are based much more on our cumulative knowledge than on our individual intelligence.
In other words, it is teamwork and the ability to pass on and share findings and technological innovations that are our main strengths.
We are laying additional bricks on the incredible wall of knowledge, discovery and innovation left by our predecessors. This collective intelligence, even if it is often very difficult to discern on social networks, would be to the success of Sapiens what these mutations are to Omicron by allowing it to become the most contagious and to partially escape vaccines.
Even if the hypotheses on the disappearance of Neanderthals are numerous, one thing is certain: long remained away from visitors, the species has bowed out after only ten thousand years of spatial coexistence with the Sapiens.
The essential role of melanin and vitamin D
Our species inherited competitive advantages which opened the way to the indisputable superiority that would have led to the disappearance of Neanderthals. In fact, Neanderthals are often said to be extinct, but in truth, they are still there, as lighter-skinned Sapiens mutants (whites), or Toubabs in Wolof, still carry genes from said extinct. It is not known if the two species of humans waged war, but genetic archeology has largely proven that they made love. Part of the Neanderthals therefore slumber among the Toubabs, who are indeed variants of the original Sapiens, no offense to the hoods who still bother us with the purity of their race! Indeed, since the triumph of Sapiens, other mutations in its genome have generated these adaptive variants that are the Toubabs. How? ‘Or’ What ? A story of sunshine and vitamins tackled by Henrich in his book and which I must tell you.
If you are a human who lives near the equator where the sun is particularly fierce all year round, like Boucar’s ancestors, it is better to have dark skin and a lot of melanin to counter the harmful effects of ultraviolet rays on your health. . Indeed, UVB and UVA rays degrade vitamin B9, also called folic acid. However, this vitamin is very important during pregnancy. When a pregnant woman is deficient in vitamin B9, fetal malformations and premature delivery are never far away. The most well-known of these pregnancy problems linked to this vitamin deficiency is an abnormality in the closure of the neural tube called spina bifida. In men, vitamin B9 is important in sperm maturation. The presence of melanin therefore plays a major role in reproduction. We then understand the evolutionary importance of having darker skin in places with very strong sunshine throughout the year. The often very difficult life and the skin problems of African albinos under the hot sun are an example to remind us of the essential role of melanin.
When the Sapiens variant arrived in less sunny climates, another problem would quickly threaten its balance: vitamin D deficiency. Involved, moving away from the equator, melanin, which was an advantage, became less. adaptive. It blocks too much the UVB rays essential for the synthesis of vitamin D. Nature has therefore flanked the Sapiens with mutations allowing them to more efficiently synthesize vitamin D, which is essential for the health of bones, cartilage, teeth and to avoid rickets. This vitamin also plays a role in muscle health and even in mental health.
Moreover, before discovering the regular intake of vitamin D supplements during the winter, I went so far as to oddly attend tanning salons to chase away the grayness that made me smile at the end of autumn.
And if there is one thing that I repeat to all Africans like me that I meet in Quebec, it is to take vitamin D supplements, because for the same time of exposure to the sun, Toubab’s skin synthesizes this vitamin much more effectively than dark skin. But on the other hand, the low melanin content of the Toubab’s skin predisposes it to other health problems, less common in dark skin like Boucar’s.
It is therefore for this story of vitamin D that nature has selected in human populations variants with more or less fair skin in regions of the globe above 50 to 55 degrees latitude, says Joseph Henrich, who recalls throughout his book that culture shapes our genes and genes in turn shape culture. It is mainly for this reason that human variants with blue and green eyes appeared among the Toubab peoples of the sea around the Baltic. Indeed, in this region, the practice of agriculture already 6000 years ago was at the origin of other changes. By abandoning the life of hunter-gatherers, for diets based on cereals, some populations of the Baltic region have gone through periods of vitamin D deficiency. Without seafood and hunting products that were part of the menu of their ancestors hunter-gatherers and provided them with vitamin D supplements, the deficiencies manifested themselves. To counter these undesirable effects, numerous mutations have thus favored the emergence of Toubabs with even lighter skin in this region. A gene called HERC2, which is located on chromosome 15, contributed substantially to this change. In addition to further lightening the skin, this gene aids in the production of clear eyes by reducing the synthesis of melanin in the iris. In other words, by wanting to further lighten the skin to improve the synthesis of vitamin D in these Toubabs, nature has indirectly generated these other variants that are people with blue or green eyes.
These ocular phenotypes are side effects of the need to create “supertoubabs” to more effectively synthesize vitamin D absent from the diet. We suspected it, but it is now scientifically proven: Pamela Anderson is a mutant.
All this long text to say that our history, which is made up of mutations, replacements and variants, is not very different from that of the virus we are fighting. Even Santa is an adaptive variant and his beard has an evolutionary role. You didn’t know, but it serves to collect cookie seeds more efficiently than a Swiffer duster.
Happy Holidays !