Question: What roles do chromosomes play in space?

The same role as they would play anywhere else, I suppose. They play a critical role in reproduction, and carry the essential ingredients to build lifeforms. These basic roles would be maintained in space, but I suppose what is not clear is how a zero gravity environment (assuming you are talking about living in space without artificial gravity) would affect the function of reproduction and other biological processes. Life is fairly closely tuned to existence on Earth, with a gravity at the surface of 9.8 metres per second squared. Taking life out of that environment and into zero gravity would be a big change and chances are, over time, that the processes of life would self-adjust to the new environment.