​Metaphase
Definition
Metaphase is a stage during the process of cell division (mitosis or meiosis). Normally, individual chromosomes are spread out in the cell nucleus. During metaphase, the nucleus dissolves and the cell’s chromosomes condense and move together, aligning in the center of the dividing cell. At this stage, the chromosomes are distinguishable when viewed through a microscope. Metaphase chromosomes are used in karyotyping, a laboratory technique for identifying chromosomal abnormalities.
Narration
Metaphase. The fact that chromosomes could be seen in metaphase via the microscope allowed them to be identified as containing the genetic material many, many years before we knew what that material was. It was later shown that chromosomes are made up of protein and DNA, and that the information in the genetic material in the chromosomes was encoded by DNA.
