The human cell can divide in two ways: Meiosis, in which the number of chromosomes is halved, producing four gametes. This type of cell division is required for the production of egg and sperm cells for sexual reproduction. The other type of cell division is Mitosis which occurs when more cells are needed. Through the process of mitosis two identical cells which are also the same as the parent cell are produced.
Many errors can occur during both types of cell division causing complications within the human body. During the process of meiosis, chromosomes are designed to split and travel to different areas in the dividing cell. This is commonly referred to as disjunction. However, sometimes an error can occur when one cell does not divide and the whole pair travels to the same area. From this error, 24 chromosomes would be in proportion with …show more content…
One cell ends up have two 21st chromosomes instead of one hence the name trisomy 21. Trisomy 21 translates to an extra chromosome being present due to a failure of cells splitting during meiosis. Some cases of trisomy 21 can occur due to Robertsonian translocation which is a type of rearrangement formed by the fusion of whole long arms of two acrocentric chromosomes (chromosomes with the centromere near the very end). Within Robertsonian translocation, while the number of chromosomes remains normal, there is a triplication of the 21st chromosome