Larger than a poppy seed but smaller than a sesame seed, and almost without distinctive features to the human eye, nematodes are very good at differentiating their relatives. In fact, they are so good that cannibals among them eat any other nematode in sight, except their own young. Now, researchers say they know why.
The scientists began by examining the nematode. Pristionchus pacificus, a worm that often lives on beetles. Some survive only with bacteria, but others are predators that consume other nematodes, even those of the same species. But the researchers were baffled by the fact that even the cannibalistic worms never ate their own relatives.
Then, the scientists compared the genomes of their laboratory nematode and another species of nematode to see if any gene could help in this so-called self-recognition. When they were modified P. pacificus worms that use the CRISPR gene editing technique, discovered a gene they call SELF-1 He was responsible for the protection of relatives. When the DNA of SELF-1 was changed, the offspring was consumed, they report today in Science.
The researchers also discovered that part of the SELF-1 The gene varies widely among nematodes, which leads to slightly different molecules in the skin, even from closely related individuals. The researchers hope to learn what molecular mechanism makes the self-recognition gene vary so much and what other molecules are involved in telling relatives that are unfamiliar, something that could help us understand self-recognition in other species.