Chromosome segregation

Chromosome Segregation is a fundamental process that occurs during cell division to ensure that each daughter cell receives an equal and correct number of chromosomes. This process is crucial for maintaining the genetic stability of an organism.

Overview

During the cell cycle, the cell duplicates its chromosomes during the S phase (synthesis phase) to ensure that each daughter cell receives a complete set of chromosomes. This is followed by the segregation of these duplicated chromosomes during mitosis or meiosis, depending on the type of cell division.

Mechanism

The mechanism of chromosome segregation varies between eukaryotes and prokaryotes due to differences in their chromosome structure and cellular organization.

In Eukaryotes

In eukaryotic cells, chromosome segregation occurs during mitosis and meiosis. During mitosis, the duplicated chromosomes align at the metaphase plate and are then pulled apart by the spindle apparatus to opposite poles of the cell. This ensures that each daughter cell receives an identical set of chromosomes.

During meiosis, a similar process occurs, but with two rounds of cell division following a single round of DNA replication. This results in four daughter cells, each with half the number of chromosomes of the parent cell. This is crucial for the production of gametes in sexual reproduction.

In Prokaryotes

In prokaryotic cells, chromosome segregation occurs during binary fission. The circular chromosome is replicated and the two copies are separated to opposite ends of the cell. The cell then divides, resulting in two daughter cells each with a single copy of the chromosome.

Errors in Chromosome Segregation

Errors in chromosome segregation can lead to aneuploidy, a condition where a cell has an abnormal number of chromosomes. This can lead to various genetic disorders, including Down syndrome and cancer.

See Also

• Cell cycle
• Mitosis
• Meiosis
• Aneuploidy