When a cell divides, the genetic information is apportioned equally into both resulting cells. To do this, fibres cluster around the two strands of each chromosome to pull them apart. However, the process is never perfect and generates genetic faults that cause our tissues to age and, in certain circumstances can also trigger cancer. Scientists have found a protein called POLO that plays a crucial role in regulating cell division. Here, we see two cells, taken from fruit flies, in the process of dividing. White spots show the points where the fibres (stained green) have attached to the chromosome pair (coloured blue) to pull it apart. On the right, the spots are arranged in neat pairs, showing normal cell division. But in the cell on the left, without POLO, the spots are disorganised, indicating that the chromosomes are being pulled apart unequally, causing the cell serious damage.
Written by Mick Warwicker