Final answer:
A non-functioning PDX-1 mutation can cause improper development of pancreatic beta cells, leading to insufficient insulin production, and potentially result in diabetes, reflecting the detrimental effect that critical gene mutations have on cellular functions.
Step-by-step explanation:
When the PDX-1 gene is mutated and non-functional, it has significant ramifications for pancreatic development and insulin production. PDX-1, also known as pancreatic and duodenal homeobox 1, is a critical transcription factor for the development of the pancreas and is essential in the maturation and function of beta cells, which produce insulin. A non-functioning PDX-1 can lead to various forms of diabetes, as the beta cells may not develop properly or may be unable to produce sufficient amounts of insulin. This mirrors the role that p53 mutations play in cellular function, as they can lead to unchecked cell division and potential tumor development due to a failure in cell cycle checkpoints and the inability to initiate apoptosis in cells with damaged DNA.