By genetically modifying organisms, we can now create glow-in-the-dark cats and fish, mice with singing voices, less flatulent cows, carbon-capturing plants, humanized cow milk, and even trademark pigs that poop environmentally-friendly feces.

Scientists are hard at work trying to grow human organs in labs and are even considering altering cattle's genome so that they feel less or no pain.

CRISPER/Cas9-based methods can target the genome of living cells, and new CAR-T gene therapies for treating cancer have opened up entirely new horizons in medicine.

If you could make anything, what would you create?

Few scientific discoveries have caused as much excitement and fear as that of editing our genes to match our very own specifications. Yet we owe some of the most stunning wonders around us today to old-fashioned breeding practices.

Charles Darwin was in such awe of breeders who could alter flora and fauna in the span of 30 or 40 years that he used the word "plastic" to describe the extreme pliability of reproductive species. "Breeders," he wrote in On the Origin of the Species, "habitually speak of an animal's organization as something quite plastic, which they can model almost as they please."

During Darwin's time, husbandry was more of an art than a science. Making perfect matches concerned the haute bourgeoisie as much as the breeders who worked for the landed gentry.

Could Darwin push nature's plasticity further than they had by approaching it scientifically?

"The pear," he wrote, "though cultivated in classical times, appears, from Pliny's description, to have been a fruit of very inferior quality." Since ancient times, the fruit had been slowly bred to become much more juicy and savory. Botanists plumped up the gooseberry over generations, created many admirable varieties of strawberries, and enhanced the beauty of cultivated flowers. According to his biographer Janet Browne, Darwin looked at nature as would an "all-seeing farmer in the sky."

The masters of this ancient art sold their genetic wonders at a pretty penny. Their very livelihood depended on keeping the secrets of their practice out of scientific journals.

Darwin speculated about the possible existence of a being who could produce even more wonderful creations than those so far created by European breeders. This being could adapt "living beings to his wants — may be said to make the wool of one sheep good for carpets, of another for cloth." Darwin offered few details about how such a talented being would go about his business, since no one, not even he, knew the precise laws governing genetic inheritance. "Your imagination must fill up very wide blanks," he told the American naturalist and Harvard professor Asa Gray, with whom he discussed this possibility.

For Darwin, breeding was a magical craft that not only gave us delicious fruit, dairy, meat, and soft materials with which to clothe ourselves, but also canine companions, such as King Charles's spaniel. The Royals' lapdog obsessed him as much as the finches of the Galapagos Islands he encountered during the voyage aboard the Beagle.

Figuring out the laws of pedigree had a scientific and personal importance for Darwin. Soon after reaching the conclusion that "a wife is better than a dog," Darwin married his first cousin Emma Wedgwood. He started reproducing copiously (as a healthy Victorian gentleman was wont to do) fathering William, Anne, Mary, Etty, George, Elizabeth, Francis, Leonard, Horace and Charles, but three of his children would die in childhood.

Designer babies were yet to come, but designer pigeons were highly coveted in Victorian times. Before breeding his own family, Darwin had tried his hand at designing some pigeons himself. He attentively observed which traits became inherited and which ones disappeared, keeping careful notes of his results. "I crossed some uniformly white fantails with some uniformly black barbs, and they produced mottled brown and black birds," he wrote. He then bred the offspring and carefully analyzed the characteristics of the next generation.

Could Darwin apply science to advance breeding practices and perhaps even help his country? He marveled at the long skinny legs of the greyhound, the exceedingly short stocky ones of the bulldog, the bulging udders of diary cows, and the long tails of certain birds. He was proud of England's breeding experts, noting with approval how "the whole body of English racehorses have come to surpass in fleetness and size the parent Arab stock." Elsewhere, he speculated about the possibility of producing "a new race."

Altering species, in Darwin's view, was almost a black art, but not quite so. He reviewed "highly competent authorities" who attested to the extreme pliability of certain species, citing favorably the statement by one such expert: "It is the magician's wand, by means of which he may summon into life whatever form and mould he pleases." Darwin also reprinted the statement by another practitioner who compared the practice of designing breeds to painting: "It would seem as if they [breeders] chalked out upon a wall a form perfect in itself, and then given it existence."

The British naturalist eloquently argued that we should "no longer" look at species "as a savage looks at a ship." But rather see them "in the same way as when we look at any great mechanical invention as the summing of the labour, the experience, the reason, and even the blunders of numerous workmen."

The century after Darwin published his Theory of Evolution was marked by the development of eugenics with its horrible excesses — including genocide, mass euthanasia and forced sterilization; the one after that by new reproductive technologies, cloning, and genome editing.

Today's techniques are much more sophisticated — and quick — than they were during Darwin's time. Our knowledge of evolution has been much refined. Instead of comparing the production of a new breed to imitating an artist's drawing, a sculptor's mold, or waving a magician's wand, scientists now commonly think of it in terms of rewriting DNA as if it were computer code.

The thrills and risks of creating custom-made forms of life are as pertinent now as they ever were. For whom, to what end, and at whose expense are we willing to go to effect these changes? Darwin never asked. The goods and wares of the luxury marketplaces in London were just too good to pass up. Darwin only dreamed of having more.

Jimena Canales is a faculty member of the Graduate College at University of Illinois, Urbana-Champaign and a research affiliate at MIT. She focuses on 19th and 20th century history of the physical sciences and science in the modern world. Her most recent book is titledThe Physicist and the Philosopher: Einstein, Bergson and the Debate That Changed Our Understanding of Time.You can learn more about her.

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