Mutants

from: le Nouvel Observateur, 23-03-2014.

Fabien Gruhier
translation: doxa-louise


Could We Be Mutants?
Mankind is now changing at a pace which has little to do with Darwinian evolution.Interview with the biologist Jean-François Bouvet, whois publishing a fascinating essai on current mutations.

Obs In a few decades, 'Homo Sapiens' seems to have really changed, without ever having experienced true genetic mutations.

J-F Bouvet Yes, that is what interests me, and is the object of my book, because we have never seen anything like it, not with man, not with any other species; this change, happening 'live', under our very eyes. Because evolution, in its true speed, operates in an invisible fashion.

But the current lot of humans have become - on average, and at breathtaking speed on the biological time-scale - taller, and more obese; they live much older; the age of puberty is lower, especially for girls, while the sperm of boys contains 40% les spermatozoa than forty years ago; these same boys now show a diminution of ano-genital distance, that which separates the anus from the posterior base of the testicular envelope, a measure of feminization - just as the accompanying lowering of testosterone levels, reported by many studies; and consequent to living indoors, and looking at near screens instead of far horizons, the proportion of the near-sighted is explosive.

Our intestinal flora is being modified to the tune of new foods, making us inapt at digesting old ones - thus multiplying allergies. These changes are occuring at an extremely fast pace. Even if we have little 'evolved', it has become impossible to say that modern man has not changed since the Neolithic.

Obs Might humanity, with increasingly artificial living conditions, have escaped nature, hence Darwinian evolution?

J-F Bouvet It is true in good part: thanks to the progress of medecine, many humans, which nature woud have condemned, attain reproduction age, and thus propagate their genes. Although natural selection has not completely disappeared and offers some resistance.

We can see this with certain illnesses, such as malaria, which kills children before the age of reproduction - and thus stops them from reproducing their vulnerability with respect to the parasite. And the fact of eating increasingly soft foods, cut-up beforehand, reduces the role of the mastication apparatus, which grows smaller - and raises problems with wisdom teeth which have become useless.

But it is clear that we are less and less 'children of Darwin', and that other change factors are at work - by mores, medecine, nutrition and especially ... buying power man is thus under the influence of things that are dependent upon him.

We have factors here which are, for many, potentially reversible: thus, the lengthening of life expectancy, coupled with the economic crisis, might well be at risk to not sustain itself - and, in the meantime, to translate into a gain in years ... of illness. Inserm statistics already show that, for France, life expectancy without chronic illness is diminishing.

Obs There is thus not much to be gained in extrapolating the future of mankind with Darwinian concepts?

J-F Bouvet No, because we have no idea what the constraints for our species will be. Man will always seek to adapt, but to what? To what demands climatic, economic, sanitary, demographic, nutritional, energetic will he have to respond...? We don't know.

The British daily The Sun had tried in 2012 such an exercise, with accompanying drawings, to draw the factorized-portrait of Homo Sapiens year 3000: quite tall, but degenerate, with s teeth and testicules, long arms and a reduced brain ( caused by ever-present computers), and large eyes (for communication more visual than oral), etc. But we have here tabloïd ravings, without the least scientific underpinnings, anyway impossible.

Obs Contrary to what we thought after the long-awaited de-coding of the human genome, the human animal - no more than any individual from another species - cannot be reduced to his genes. And two clones are never quite identical.

J-F Bouvet Indeed, the given has changed quite a bit, and one must today deal with epigenetics - the way in which genes express themselves, or not, or diffrently, as a function of the conditions encountered in the environment, or the personnal history of the individual.

Thus our genes are inflenced in their mode of expression, for example by chemical pollution. Theyr are thus modualted, and transmitted as such to their descendants - like a bit of 'unrebooted' computer memory.

This is the manner in which chemical attacks - like those due to endocrine disruptors, or to medecines which inhabit our universe - become, the most genetically possible, transmitted to our descendants. This has been shown with mice: there is a transmission of acquired charactersistics, which recalls somewhat the discredited theories ofthe biologist Lamarck.

Obs But follows that it is impossible to create a series of true clones, which liberates us from an old fear.

J-F Bouvet Yes, but only to replace it with a new one, scientifically validated for this one through experimentation on animals: over many generations, a number of perverse effects are inherited, undesirable, from toxic substances ascendants have been exposed to.Will these nasty modifications perpetuate themselves indefinitely, until finally the genes involved re-assert themselves (in their initial state)? We don't know, but until now, experimenting over generations of mice, this return to normal has not been seen.

Even if we could miraculously rid ourselves, they would remain dispersed in our lands, waters, soils. And especially, through epigenetics, even dismantled, they would continue to act on our desendants, through effects we call intergenerational.

Obs The size, and height of humans, has changed quite a bit over millenia, and even over centuries, not always as expected.

J-F Bouvet At least in most of the developed counties today, humans are getting dramatically taller. On deduces from this that the phenomena is caused by better food and living conditions. We have proof, a contrario, by a comparison between North abd South Korea.

After a hefty half-century of a closed border, the result, unfortunately, is probing: North Korean teen-agers are on average 20 centimeters shorter than their South Korean counterparts. Only dictators Kim Jong-il and Kim Jong-un, father and son, could permit themselves such a conclusive 'scientific' experiment - on humans, rather than rats!

Obs Mankind's emergence, even correctly fed, has not always been straightforward...

J-F Bouvet In fact, it is a kin od yo-yo: during the Paleolithic, men and women were as tall if not taller than those today. But the subjects of Louis XIV had shrunk to 6 centimeters than the French of the Middle Ages...

One thougth it might be possible to plot these changes against different factors, such as food supply, and temperature changes: the warmer it gets, the more one needs surface temperature to evacuate thermic calories. In effect, global warming should entice us to grow a bit more... given adequate nutritional sources.

Jean-François Bouvet, docteur es sciences, biologist and essayist.
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