What is chromosome biology?

When Watson and Crick’s revealed the “double helix” as the structure that transmits our genetic inheritance they gave us one of the strongest images in science. For decades after 1953 scientists and non-scientists focused on DNA as the basis for understanding how molecules lead to biology and life.

Ironically, it has been by obtaining the ultimate picture of DNA through determining the human genome sequence that our perspective has changed. The vastness of our DNA and the inherent challenges for the cell in managing it has been brought home. The 3 billion chemical ‘basepairs’ held in each human cell represent about the same number of letters as contained in all the print of books in a typical city library. Yet the simple sequence of the double helix alone does not provide enough ‘blueprint’ to determine what occurs in the cell.

An important additional component of genetics is the packaging that envelops DNA, and this plays a crucial role in encoding and enabling life. The packaging is called ‘chromatin’: the material that makes up ‘chromosomes’ into which our genome is divided. The study of chromatin and chromosomes is the foundation of our research in the Centre for Chromosome Biology.

Chromosomes were first observed within the human cell nucleus in the middle of the 1800s, and recognised as the carriers of genetic information by the 1900s. The place of DNA at their heart was confirmed by the middle of the last century, but the focus on DNA as the genetic material led to the view that chromosomes were mainly a convenient packaging for DNA. Of course packaging is clearly crucial: A typical protein could be coded on roughly one book page whereas the entire human genome equates to a city library, so order is essential.

The crucial point is that a cell must find, maintain, distribute and faithfully copy every ‘page’ of protein information within its DNA library to enable life. That’s a similar task to finding, curating and publishing facts for a homework assignment constantly for millenia, and the cell has no Google or Wikipedia!

To make the management of printed information efficient, libraries are organised systematically into rooms, shelves, rows of books, chapters within them, and finally the numbered book pages themselves. Likewise, the chromosome has a hierarchical order from the familiar X shape (found only a certain point in each cell generation) down through many smaller levels to a cotton-reel like molecular packaging on protein spindles which is the building blocks of chromatin equivalent to the page of a book.

Our work in the Centre for Chromosome Biology revolves around understanding the makeup of chromatin, and the processes which act on it to provide all the functions needed to sustain life. Being a complex system, there are unfortunately many ways that the molecular mechanisms can go wrong and lead to diseases like cancer so our research can also make a contribution to future health.

This is Chromosome Biology.