How spiders got their knees | Science/AAAS | News

A gene named after the stumpy legs of wiener dogs may give spiders and scorpions their knees. That’s the surprising result of a new study, which finds that an ancient duplication of the so-called Dachshund gene has provided arachnids the ability to swiftly scuttle across silken webs, piles of leaf litter, and even the kitchen floor. The gene, also present in fruit flies and mice, could provide insights into how DNA duplication gives rise to new body shapes.

Still, there are other arachnids like mites that have kneecaps but no copy of the Dachshund gene, says Prashant Sharma, an evolutionary biologist at the University of Wisconsin, Madison, who was not involved in the work. “Reconciling how that occurs is something the study needs to grapple with before it can claim that one particular gene copy explains how all arachnids have patellas.”