Softly, softly

摘要

PHYSICS IS FAMOUS for mind-bending ideas. Subatomic particles can be in many places at once. The flow of time depends on how fast you are moving. But because such ideas are confined to the realm of the invisibly tiny or the inhumanly vast, most people regard them as little more than diverting curiosities. Biology has mind-bending ideas, too. Since they may concern the everyday world of living bodies, their impact is often felt much more viscerally. One example is "chimeras", organisms which, a bit like the mythological beast, are formed from cells of two distinct species. Scientists have already produced goat-sheep and mouse-rats. Now a group of American, Chinese and Spanish researchers has reported significant progress in the quest to create chimeras using human cells-in this case, combining them with cells from monkeys to form functioning embryos (see Science & technology section).