昆虫为什么会有6条腿?美国进化生物学家经过多年研究,最近对这个问题作出了回答。他们通过杀灭两个基因,迫使甲虫幼虫长出16条额外的腿,从而重新制造出其祖先早在大约4亿年前就丧失了的肢体来。昆虫及其他节肢动物,是从类似当今的千足虫和蜈蚣那样的动物进化而来的。这些千足虫和蜈蚣,有许多分离的、无特定功能的身体部节,每部节都有自己的一双腿。仅有6条腿的昆虫,比起多腿的祖先来要灵敏得 Why do the insects have six legs? After years of research, American evolutionary biologists have recently answered this question. By killing two genes, they forced the beetle larvae to grow 16 extra legs, thereby recreating the limbs that their ancestors lost as early as 400 million years ago. Insects and other arthropods have evolved from animals like the millipedes and cockroaches of today. These millipedes and cockroaches have many isolated body parts with no specific function, and each section has its own pair of legs. Only 6-legged insects are more sensitive than their ancestors