consecutively, i.e. asynchronously. Then, it should not surprise us that in
living nature the asynchronous division has been estabished as a natural
biological process. It is more suitable in view of potential energetic
possibilities of the cells, depending on a number of factors including the
conditions of surroundings.
Often in the literature the terms “synchronous” and “asynchronous”
cell culture are mixed up with those of synchronous and asynchronous
division. Obtaining synchronous cultures is achieved by using definite
methods in order to lead the cell population to the same phase of
development, while synchronous or asynchronous division is the mode of
realizing the reproduction in the time. The synchrony index varies but
never achieves 100%. That is why it is better to use the terms
synchronized and asynchronized cell culture instead of synchronous and
asynchronous. According to Mazia (1963) “nobody has succeeded to
force cells to grow synchronously and to maintain such a synchrony for a
long time”.
The cause for impossibility to obtain completely synchronized cell
cultures is the asynchronous nuclear division and daughter cell formation.
Because of that the nuclei available in mother cells, though having equal
genetic material, are not equalized regarding their mitotic stage. That is
why the extent of synchronization of a given population should be
considered relative and cannot be determined only on the basis of the
number of nuclei and morphological characteristics. It is also necessary
to take into consideration the phases of development of the nuclei in cells
that are synchronized.