Question

Biochemistry textbooks published a few decades ago often used the phrase “one gene, one protein.” Why is this phrase no longer accurate?

Answer 1

Genes are the functional areas of DNA which are transcribed to RNA and translated to proteins. One gene one protein hypothesis is the idea that one gene produced a single polypeptide.

Now this concept is not valid because of the discovery of the concept of splicing.

RNA is subjected to splicing after transcription. RNA contains several non coding regions called introns that exist in between various coding areas of genes called exons.

During another process called alternative splicing, multiple exons are joined together and now a single mRNA from a single gene can translate many proteins.

So now one gene one protein concept is not valid.