Genetic material, DNA, is distributed over our chromosomes. These long, stringy structures consisting of the well-known double helix are stored in the nucleus of the cell. Benjamin Rowland of the Netherlands Cancer Institute: “We have conducted exciting experiments in which we saw that the chromosomes suddenly organized themselves differently in the nucleus once we removed the protein complex condensin II.”
“Human chromosomes are organized in the cell nucleus like individual nests of dry noodles. They all have their own territory,” Claire Hoencamp, PhD student in Rowland’s research group, explains. “Somewhere in the middle of those nests is a centromere, the center of the chromosome. If you remove condensin II, all centromeres of these various chromosomes suddenly cluster together, so you lose those individual nests.”
Rowland presented these surprising results during a conference held in a small castle in Austria. One of the attendees was researcher Erez Lieberman Aiden from Texas, who recognized these transformations in chromosome folding in humans from his own research into mosquitoes and mushrooms.
A spontaneous conversation grew into a large-scale collaboration between multiple teams in Amsterdam, Houston, and Boston. As part of the DNA Zoo consortium, the researchers in Houston collected materials from zoos all over the world. This allowed them to map out the way chromosomes are organized throughout the animal kingdom, in plants, and in fungi. They noticed that organisms often have either one type of chromosome folding (separate nests, like in humans) or another type of folding (centromeres clustered together, as seen in mosquitoes). As it turned out, organisms that naturally lack condensin II do not have these separate nests.