What is the evolutionary significance of alternative RNA splicing?

• A. It can silence genes, giving cells another way of controlling gene expression.
• B. Because it is not specific to a cell type, alternative RNA splicing can make sweeping changes in gene expression, allowing an organism to adapt quickly to new situations.
• C. It acts as a defense against viral RNA, helping organisms avoid infection, particularly by cancer-causing viruses.
• D. The introns that are spliced out can become miRNAs and can recognize and degrade mRNA transcripts.
• E. It expands the number of proteins that can be coded for by one gene, increasing an organism's ability to produce novel proteins.

Answer: (E)

Verified step by step guidance

1. Understand that alternative RNA splicing is a process during gene expression where a single gene can lead to multiple protein products. This is achieved by varying the combination of exons included in the final mRNA transcript.
2. Recognize that this process allows for the generation of protein diversity from a limited number of genes. This is significant in evolutionary terms because it enables organisms to adapt to new environments and challenges by producing a variety of proteins with different functions.
3. Consider that alternative RNA splicing can lead to the production of proteins with different functions or properties, which can be advantageous for survival and adaptation. This increases the functional repertoire of an organism without the need for additional genes.
4. Acknowledge that this mechanism is crucial for complex organisms, where different tissues or developmental stages may require different protein variants. It allows for tissue-specific and developmental stage-specific protein expression.
5. Conclude that the evolutionary significance of alternative RNA splicing lies in its ability to expand the proteome, providing organisms with the flexibility to evolve new functions and adapt to changing environments, thereby enhancing their evolutionary fitness.