Isolating specific cell types from a mass of plant or animal tissue is laborious and tricky. To study epigenetic changes and genes that are expressed differently in different cell lineages—such as cancer cells versus normal cells, or the two types of epidermal cells in Arabidopsis roots—typically requires laser capture microdissection (LCM) or fluorescence-activated cell sorting (FACS). LCM uses a laser and a microscope to literally flip individual cells out of a tissue into a container. It’s like playing tiddlywinks, says Elizabeth Dennis at CSIRO in Canberra, Australia, but you have to flip out a thousand individual cells for each experiment. “It’s a real pain,” she says. Like FACS, it also requires expensive equipment. Roger Deal and Steven Henikoff from the Fred Hutchinson Cancer Research Center have developed a cheap and easy method, dubbed “isolation of nuclei tagged in specific cell types” (INTACT).
A sequencing study suggests that some genes have evolved in parallel in humans and their canine companions, likely as a result of shared selection pressures.