Scientists at Fred Hutchinson Cancer Research Center have worked out the molecular underpinnings of how chromosomes make the right number of crossovers — important links that make it possible for developing sex cells (eggs or sperm in humans) to sort those chromosomes properly. Crossovers are a little like Goldilocks’ porridge — they need to be just right. Too few or too many crossovers, and new cells end up with the wrong number of chromosomes, which can cause miscarriages or developmental disorders.
It’s been known for 100 years that our chromosomes have a way of preventing too many crossovers along their length. What’s been missing all that time has been a working model that identifies the key molecules involved.
In work published today in the Proceedings of the National Academy of Sciences, Hutch molecular biologist Dr. Gerry Smith and his team outline just such a model in yeast that explains how chromosomes find their happy medium during sex-cell formation.
“What’s significant is that we’ve developed a molecular model of the proteins involved and how they work together to create crossover interference,” said Smith, the study’s senior author.
