Slashdot reader omfglearntoplay shares an excerpt from a BBC article that explores the new technologies that may have already introduced genetic errors to the human gene pool. The article starts by mentioning He Jiankui, a Shenzhen researcher who was sentenced to prison in late 2019 for creating the world’s first genetically altered babies. From the report: Jiankui had made the first genetically modified babies in the history of humankind. After 3.7 billion years of continuous, undisturbed evolution by natural selection, a life form had taken its innate biology into its own hands. The result was twin baby girls who were born with altered copies of a gene known as CCR5, which the scientist hoped would make them immune to HIV. But things were not as they seemed. In the years since, it’s become clear that Jiankui’s project was not quite as innocent as it might sound. He had broken laws, forged documents, misled the babies’ parents about any risks and failed to do adequate safety testing. However, arguably the biggest twist were the mistakes. It turns out that the babies involved, Lulu and Nana, have not been gifted with neatly edited genes after all. Not only are they not necessarily immune to HIV, they have been accidentally endowed with versions of CCR5 that are entirely made up — they likely do not exist in any other human genome on the planet. And yet, such changes are heritable — they could be passed on to their children, and children’s children, and so on. In fact, there have been no shortage of surprises in the field. From the rabbits altered to be leaner that inexplicably ended up with much longer tongues to the cattle tweaked to lack horns that were inadvertently endowed with a long stretch of bacterial DNA in their genomes (including some genes that confer antibiotic resistance, no less) — its past is riddled with errors and misunderstandings. More recently, researchers at the Francis Crick Institute in London warned that editing the genetics of human embryos can lead to unintended consequences. By analyzing data from previous experiments, they found that approximately 16% had accidental mutations that would not have been picked up via standard tests. Why are these mistakes so common? Can they be overcome? And how could they affect future generations?