Final answer:
The mechanism that enables the production of different polypeptides from the same DNA sequence is RNA splicing, specifically alternative splicing, which can include or exclude certain exons or introns in the final mRNA.
Step-by-step explanation:
The mechanism that allows for the production of polypeptides that are not entirely encoded by DNA is c) RNA splicing. RNA splicing is a part of post-transcriptional regulation, where introns are removed, and exons are joined to form a mature messenger RNA (mRNA). This mature mRNA then leaves the nucleus and enters the cytoplasm where it can be translated into a polypeptide.
One specific form of splicing, known as alternative splicing, allows for the generation of different proteins from a single gene by including or excluding certain exons or introns, resulting in different mature mRNA molecules that encode for various polypeptides.
During the process of alternative splicing, a single gene can give rise to multiple proteins, contributing to the complexity and diversity of proteins in eukaryotic organisms. According to estimations, about 70% of human genes undergo alternative splicing, making this mechanism significant in gene expression and regulation.