The architect of that strategy is Martin Chalfie, of Columbia University in New York. He co-authored a 1981 paper on molecular mechanisms of touch in C. elegans and led mutagenesis screens for sensory genes. In a series of experiments, researchers attached eyelashes to toothpicks and prodded and brushed the sides of worms to identify touch mutants. Over the next decade or so, Chalfie, Driscoll and others isolated the 12 worm genes required for sensing touch and pinpointed the six worm touch receptors. Touch receptors in C. elegans consist of ion channel proteins.
Ion channels are pores in the membranes of nerve cells through which sodium flows.
The mechanical opening and closing of channels leads to the conversion of a stimulus, such as a poke, into electrical impulses. Many in the field hypothesize that touch receptors in mammals are complexes of ion channel proteins, but the proteins themselves are elusive. One receptor can feel things across a relatively broad area. Touch receptors are found in places that are generally inaccessible to researchers. The BNC1 gene, for example, is expressed below the skin in the endings of nerve fibers that surround mouse hair follicles.