what structure holds the individual chromatids together

The structure that holds the individual chromatids together is called the centromere. The centromere is a region of the chromosome that is able to bind to spindle fibers during cell division. The two identical halves of a chromosome that have been replicated in preparation for cell division are called chromatids, and they are joined at the centromere. Sister chromatids are physically held together by a protein complex called cohesin. During cell division, spindle fibers attach to the centromere and pull each of the sister chromatids to opposite sides of the cell, causing each chromatid pair to separate, and each chromatid becomes a separate chromosome at this point.