Final answer:
Deletion of p53 genes leads to the loss of important tumor-suppressing functions, which can result in unchecked cell division, accumulation of mutations, and cancer growth due to the failure of DNA repair mechanisms and the inability to trigger apoptosis in damaged cells.
Step-by-step explanation:
The deletion of the p53 genes is damaging to an organism because p53 plays a crucial role in maintaining the integrity of the genome. p53 genes serve as tumor suppressors and are involved in several regulatory mechanisms of the cell cycle. If p53 function is lost due to deletion, the cell cannot halt the cycle for DNA repair or induce apoptosis in the case of severe DNA damage. This can result in cells with damaged DNA continuing to replicate, leading to the accumulation of mutations and ultimately cancer formation.During the G₁ checkpoint, p53 is responsible for detecting and responding to genomic errors. It activates DNA repair mechanisms and can even trigger apoptosis to prevent the propagation of severely damaged DNA. Without functional p53, the G₁ checkpoint fails, allowing cells to advance from G₁ to S phase and undergo division without addressing the DNA errors, resulting in tumor growth.Furthermore, mutated p53 may not be able to activate the production of p21, a crucial regulator that blocks the activation of cyclin-dependent kinases (Cdks). Without p21, the cell cycle progresses unchecked, leading to a rapid accumulation of oncogenes and additional non-functional tumor suppressor genes, which exacerbates tumor development.