As the eugenic movement peaked and crashed, advances in reproductive technology made designer babies thrillingly, frighteningly possible. In the 1920s and early ’30s, visionaries imagined divorcing love and even marriage from procreation. Reproduction could be done scientifically, rationally, in a test tube. For optimists such as the biologist J B S Haldane, such ‘ectogenesis’ would permit humans to take the reins of their own evolution, eliminating disease and mutation, and perhaps enhancing qualities such as intelligence, kindness and strength of character. ... The development of molecular biology in the 1950s and ’60s transformed genes from abstractions into hard chemicals. Suddenly, scientists understood basically what a gene was. They thought they understood what a human was. ... By the mid-1980s, enthusiasts were discussing ‘genetic surgery’. The idea was to treat genetic disease by inserting a therapeutic gene into a modified virus and then ‘infect’ the patient; the virus would do the tricky part of inserting the gene into the chromosome. Through the 1990s, gene therapy was hyped almost as hard as CRISPR (clustered regularly interspaced short palindromic repeats), the new technology for ‘editing’ genes, is today. ... in terms of bringing us closer to a science-fiction world of intelligently designing our children – utopia or dystopia, take your pick – gene editing is more precise than accurate. The qualities we want in a child or in society can’t be had by tweaking a few nucleotides. There are no short cuts. To think otherwise is to conflate power with knowledge, to overestimate our understanding of biology, and to overestimate the role of genes in determining who we are.
Above a certain temperature, a cell will collapse and die. One of the most straightforward explanations for this lack of heat hardiness is that the proteins essential to life — the ones that extract energy from food or sunlight, fend off invaders, destroy waste products and so on — often have beautifully precise shapes. They start as long strands, then fold into helixes, hairpins and other configurations, as dictated by the sequence of their components. These shapes play a huge role in what they do. Yet when things start to heat up, the bonds that keep protein structures together break: first the weaker ones, and then, as the temperature mounts, the stronger ones. It makes sense that a pervasive loss of protein structure would be lethal, but until recently, the details of how, or if, this kills overheated cells were unknown. ... One of the clearest observations was that in each species, the proteins did not unfold en masse with a temperature boost. Instead, “we saw that only a small subset of proteins collapses very early,” Picotti said, “and these are key proteins.” ... This paradox — that some of the most important proteins seem to be the most delicate — may reflect how evolution has shaped them to do their jobs. ... The more copies the cell made, they reported, the more heat it took to break a protein down.