A chromosome's glue
We all begin with one cell, which divides into two - and so on. It sounds straightforward but a cell has various components (nucleus, mitochondria, Golgi apparatus...) each of which carries out vital activities. If two daughter cells are to survive, they must receive a copy of each component from the mother cell. A mother cell cannot just split in two, pour half of its contents into one cell and tilt the rest in the second. That would be like producing two cars of the same make where one is built with no engine and the other with no wheels. Every part of a cell has a specific and an essential role, which is why each part has to be inherited by progeny. Among these essential components daughter cells must receive a copy of their mother's DNA. The only way to do this is for the mother cell to double its DNA and then distribute it in such a way that the DNA in each daughter cell is identical in quantity and nature. This can occur thanks to a mechanism known as mitosis. During mitosis, a dividing cell's chromosomes (its DNA) alternate between two opposing states: individualized and clustered. It turns out that a protein - already known to scientists - is directly involved in the making of these two chromosomal states. Its name? Ki-67.
