Its supporters dream of heat-resistant cows. But gene editing is making others nervous

BBCThere’s nothing new about genetic engineering. By cross-breeding plants and animals, our Stone Age ancestors realised they could boost the amount of food they produced.Modern genetics has enabled scientists to do much more: to make precise, targeted changes to the DNA of organisms in a lab. And that, they claim, will lead to new, more productive, disease-resistant crops and animals.The science is still in its…