Cytologists had been studying chromosome behavior since the late 19th century. Why did it take until 1956 to figure out the correct human chromosome number, thanks to Joe Hin Tjio and Albert Levan?

Centromere placement can also be used to identify the gross morphology, or shape, of chromosomes. For example, metacentric chromosomes, such as chromosomes 1, 3, and 16, have p and q arms of ...