Jonathan Nelson is a postdoc in Whitehead Institute Member Yukiko Yamashita’s lab studying how dividing cells maintain their genomes. We sat down with Nelson to learn more about him and his experiences in and out of the lab. From a broad perspective, I have an interest in understanding how cells make sure that they get everything right when they divide, especially when copying the genome, and then if they do have errors, how they correct that. We’ve been focusing on the stem cells that make sperm in the fly, because they are making the cells that make the next generation of animals, so it’s really important that they copy their genomes correctly in those cells. What we’ve been studying is a particular region of the genome called the ribosomal DNA, which is essential because it helps make the ribosomes that make all the proteins in our cells. It consists of hundreds of copies of the same gene duplicated over and over again, and because of this, it’s really unstable. It’s hard to ensure you always copy the exact right number every time, or if you get it wrong to copy the right number next time. What we found is a really surprising role for things called transposable elements, which are sort of thought of as these genetic parasites because they haven’t been found to serve many functions in the cell other than making new copies of themselves. However, we found that they’re really essential for maintaining this region of the genome in the cells that make sperm.
