The chromatids line up along the equator during the metaphase of cell division.
During metaphase, the spindle fibers attach to the centromeres of the chromosomes and align them in the center of the cell, creating a structure known as the metaphase plate. This alignment is crucial for ensuring that each daughter cell receives an identical set of chromosomes when the cell divides. The precise arrangement also helps to prevent errors in chromosome separation, which can lead to genetic disorders.