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Cell cycle includes a series of events, which leads to DNA duplication, followed by formation of new cells from a parent cell. In humans and other higher organisms, cell cycle consists of four phases, G1 (gap 1), S phase (synthesis phase), G2 phase and M phase (either mitotic or meiotic phase), in which mistakes can occur.
During G1 phase, cell prepares itself to divide and makes proteins, required for DNA synthesis during S phase. Errors occur when cell cannot make sufficient proteins and other necessary raw materials.
During S phase, DNA replication takes place to gets divided into daughter cells. Errors during S phase includes mutations and loss of DNA integrity.
During G2 phase, cell gets prepared for mitotic or meiotic division. Errors that occurred during S phase are repaired during G2 phase. Mistakes in repairing those errors result in problems as they will pass to the new daughter cells through M phase.
During M phase, separation of duplicated chromosomes into daughter cells occurs. Mistakes that can lead to errors during this phase include chromosomal abnormalities, such as polyploidy or enuploidy.
