How homologous chromosomes in the body’s cells pair along their entire lengths is a century-old riddle. Now, two studies by Wyss Institute and HMS Faculty member Ting Wu, Jelena Erceg and Jumana AlHaj Abed in the Wu group, and their collaborators Leonid Mirny (MIT), Anton Goloborodko in the Mirny group, and Job Dekker (UMass, HHMI) have shed light on this question by studying cells and embryos of Drosophila fruit flies as a genetic model organism. Their findings are also highly relevant for a wide range of phenomena, such as DNA repair, in humans and other species.
Using a novel approach, the team reveals complex forms of pairing – including different types of tighter and looser “pairing-structures”. They also uncover global connections between chromosome pairing and paradigms governing the activity of genes during, for example, the embryogenesis of Drosophila, and then extend their work to mammalian embryos.
Lastly, in an opinions piece, Wu and two other members of her group, Huy Nguyen and S. Dean Lee, speculate how pairing of maternal and paternal homologs may help cells count their chromosomes and, in mammalian females, select one of their two X chromosomes to be inactivated.