Centromere is a region of chromosomes with a special sequence and structure. The centromere plays a role in cellular division and the control of gene expression. Centromeres are those condensed regions within the chromosome that are responsible for the accurate segregation of the replicated chromosome during mitosis and meiosis. When chromosomes are stained they typically show a dark-stained region that is the centromere. During mitosis, the centromere that is shared by the sister chromatids must divide so that the chromatids can migrate to opposite poles of the cell. On the other hand, during the first meiotic division the centromere of sister chromatids must remain intact, whereas during meiosis II they must act as they do during mitosis. Therefore the centromere is an important component of chromosome structure and segregation.

Function Of Centromere
           A centromere functions in sister chromatid adhesion, kinetochore formation, pairing of homologous chromosomes and is involved in the control of gene expression. A centromere is the region where sister chromatids join in the double chromosomal structure during mitosis, prophase and metaphase. The centromere is also where kinetochore formation takes place: proteins bind on the centromeres that form an anchor point for the spindle formation required for the pull of chromosomes toward the centrioles during the anaphase and telophase of mitosis. Aberrant centromeric function can lead to improper chromosomal alignment and segregation, resulting in aneuploidy and conditions such as Down syndrome.