Centromere

The centromere is the location on a chromosome where multiple strands of DNA join to come into the typical "X" shape of a chromosome. The centromere is the location where the body seems to cross although, in reality, the centromere can be more accurately described as the foundation of the bundling of the DNA strands into a chromosome in preparation for meiosis. In addition to DNA, the centromere contains proteins and other materials used to ensure the shape of the chromosome.
Although a centromere usually is at the center of a symmetrical structure, it can appear anywhere between the two sides of the chromosome from the middle to nearly the end, and there is no necessity that the two sides be of equal length.
Dysfunctional centromeres play a role in the development of cancer and are a key factor behind miscarriage. It also appears centromere function deteriorates with age.
Centromere at Wikipedia
Category:Genetics