Recent research, however, is giving Lamarck a measure of redemption. A subtle regulatory system has been shown to silence or mute the effects of genes without changing the DNA itself. Environmental stresses such as heat, salt, toxins, and infection can trigger so-called epigenetic responses, turning genes on and off to stimulate or restrict growth, initiate immune reactions, and much more. These alterations in gene activity, which are reversible, can be passed down to offspring. They are hitchhikers on the chromosomes, riding along for a while, but able to hop on and off. Harnessing epigenetics, some speculate, could enable us to create Lamarckian crops, which would adapt to a disease in one or two generations and then pass the acquired resistance down to their offspring. If the disease left the area, so would the resistance.
All of these heredities—chromosomal, mitochondrial, epigenetic—still don’t add up to your entire you. Not even close. Every one of us carries a unique flora of hundreds if not thousands of microbes, each with its own genome, without which we cannot feel healthy—cannot be “us.” These too can be passed down from parent to child—but may also move from child to adult, child to child, stranger to stranger. Always a willing volunteer, Zimmer allowed a researcher to sample the microbes living in his belly-button lint. Zimmer’s “navelome” included 53 species of bacteria. One microbe had been known, until then, only from the Mariana Trench. “You, my friend,” the scientist said, “are a wonderland.” Indeed, we all are.
With this in mind, reconsider the ongoing effort to engineer heredity. The motto of the Second International Eugenics Congress, in 1921, was “Eugenics is the self-direction of human evolution.” Since then, controlling heredity has become technically much easier and philosophically more complicated. When, in the 1970s, the first genetic engineering made medical gene therapy feasible, many of its pioneers urged caution, lest some government try to create a genetic Fourth Reich. In particular, two taboos seemed commonsense: no enhancement, only therapy (thou shalt not create a master race); and no alterations in germ-line tissues, only in somatic cells (thou shalt not make heritable modifications).
To today’s genetic engineers, those parameters seem quaint. Researchers can now convert mature somatic tissue taken from, say, a cheek swab into stem cells able to become any type of cell, even sperm and eggs. New technologies such as the gene-editing technique known as crispr have greatly expanded the repertoire of engineering. Ethical quandaries abound. Although injecting the hormone erythropoietin can be lifesaving for people with severe anemia, it is illegal for athletes. What about gene therapy to raise one’s “natural” erythropoietin production? Is it better to eliminate gene variants for sickle cell anemia and thalassemia, or to retain the malaria resistance those genes confer? What kinds of side effects would seem tolerable in order to raise your child’s IQ by a few points?
Source : https://www.theatlantic.com/magazine/archive/2018/07/carl-zimmer-she-has-her-mother-s-laugh/561710/Thank You for Visiting My Website