Answer is centromere.
Mitosis is a method of cell division in which a cell divides into two identical daughter cells. During mitosis separation duplicated genetic material is done. This division completed in five different phases namely prophase, metaphase, anaphase and telophase.
During prophase, the duplicated pairs of chromosomes get condensed are called sister chromatids. The pair of chromosomes remain joined at a central point called the centromere (a special part of a chromosome where the two identical sister chromatids are attached).