Question

A geneticist discovers that two different proteins are encoded by the same gene. One protein has 56 amino acids, and the other has 82 amino acids. Which of the statements are possible explanations for how the same gene can encode both of these proteins? The same gene encodes both proteins by generating a poly(A) tail on the pre‑mRNA. The same gene encodes both proteins by using different combinations of exons in the pre‑mRNA via alternative splicing. The same gene encodes both proteins by using different combinations of introns in the pre‑mRNA via alternative splicing. The same gene encodes both proteins by using multiple 3′ cleavage sites in the pre‑mRNA.

Answer 1

Answer:

The same gene encodes both proteins by using different combinations of exons in the pre‑mRNA via alternative splicing.

Explanation:

According to the question, two different proteins (one with 56 amino acids and the other with 82 amino acids) are found to be encoded by the same gene. This is possible due to a process called ALTERNATIVE SPLICING.

Alternative splicing is a phenomenon whereby the protein-coding region of a gene called EXON is manipulated in such a way that variety of proteins emanate from a single gene. This manipulation includes the removal or inclusion of EXONS in the gene, so as to give rise to different combinations of mRNA, hence, different proteins will be translated from the different mRNA from the same gene.

In this case, exons were removed from one mRNA to have lesser amino acids (56) in the translated protein while exons were included in the other mRNA to have more amino acids (82).