The structure that holds the individual chromatids together is called the centromere. During cell division, specifically in the phases of mitosis and meiosis, the chromosomes are replicated, resulting in sister chromatids. These chromatids are identical copies of the chromosome formed during DNA replication. The centromere is a specialized region on the chromosome that plays a crucial role in ensuring that chromatids are properly separated and distributed to the daughter cells.
The centromere is not only a physical connector between sister chromatids but also serves as an attachment point for spindle fibers during cell division. These spindle fibers, which are part of the mitotic spindle, pull the chromatids apart in anaphase, allowing each daughter cell to receive an identical set of chromosomes. Thus, the centromere is essential for accurate chromosome segregation, which is vital for maintaining genomic stability.