Metaphase (from the
Greek μετά, "adjacent" and φάσις, "stage") is a stage of
mitosis in the
eukaryotic cell cycle in which chromosomes are at their second-most condensed and coiled stage (they are at their most condensed in
anaphase). These
chromosomes, carrying
genetic information, align in the equator of the
cell before being separated into each of the two daughter cells. Metaphase accounts for approximately 4% of the
cell cycle's duration. Preceded by events in
prometaphase and followed by
anaphase,
microtubules formed in
prophase have already found and attached themselves to
kinetochores in metaphase. In metaphase, the
centromeres of the chromosomes convene themselves on the
metaphase plate (or
equatorial plate), an imaginary line that is equidistant from the two
centrosome poles. This even alignment is due to the counterbalance of the pulling powers generated by the opposing kinetochore microtubules, analogous to a tug-of-war between two people of equal strength, ending with the destruction of B
cyclin. In certain types of cells, chromosomes do not line up at the metaphase plate and instead move back and forth between the poles randomly, only roughly lining up along the middleline. Early events of metaphase can coincide with the later events of prometaphase, as chromosomes with connected kinetochores will start the events of metaphase individually before other chromosomes with unconnected kinetochores that are still lingering in the events of prometaphase.