What is one cause for the 21,000 protein encoding sequences in the human genome producing between 200,000 and 1 million different proteins?Group of answer choicesalternative splicingCNVsrestriction sitesSNPs

The cause for the 21,000 protein encoding sequences in the human genome producing between 200,000 and 1 million different proteins is alternative splicing.

Here's a step-by-step explanation:

1. The human genome contains about 21,000 protein-coding genes.

2. Each gene is made up of exons and introns. Exons are the sequences that will be translated into protein, while introns are the non-coding sequences in between.

3. During the process of transcription, the entire gene (both exons and introns) is copied into a pre-mRNA molecule.

4. Then, during the process of RNA splicing, the introns are removed and the exons are joined together to form a mature mRNA molecule.

5. However, not all exons are always included in the final mRNA. Sometimes, certain exons are left out, or included in different combinations. This is known as alternative splicing.

6. As a result of alternative splicing, one gene can give rise to multiple different mRNA molecules, each of which can be translated into a different protein.

7. Therefore, even though there are only about 21,000 protein-coding genes in the human genome, alternative splicing allows for the production of between 200,000 and 1 million different proteins.