Question

Which of the following contradicts the "one-gene, one-enzyme hypothesis"?
A. A mutation in a single gene can result in a defective protein.
B. Sickle-cell anemia results in defective hemoglobin.
C. Alkaptonuria results when individuals lack a single enzyme involved in the catalysis of homogentisic acid.
D. A single antibody gene can code for different related proteins, depending on the RNA splicing that takes place post-transcriptionally.

Answer 1

Answer:

A single antibody gene can code for different related proteins, depending on the splicing that takes place post-transcriptionally.

Explanation:

According to the "one-gene, one-enzyme hypothesis", a gene code for single specific enzyme only. Beadle and Tatum proposed the one-gene, one-enzyme hypothesis that states that a gene encodes the genetic information for the synthesis of one enzyme only. However, alternative splicing in eukaryotes allows the formation of more than one related proteins/enzymes from a single gene.

For instance, alternative splicing of single primary transcript transcribed from an antibody gene allows the formation of multiple proteins. The primary transcript encoded by this gene has a segment of the gene that serves as either intron or exon. Depending on particular combinations of exons retained after splicing, multiple related proteins are formed by respective mRNA.