Final answer:
At least three-quarters of the human genome is involved in RNA production that regulates gene activity, with about 4 million regulatory sites identified. Only 1 to 2 percent of the genome codes for proteins, with the rest comprised of regulatory elements and non-coding DNA.
Step-by-step explanation:
Many of our genes do not directly code for proteins but are instead involved in the regulation of gene expression. It is now understood that at least three-quarters of the human genome is involved in making RNA, much of which is not translated into proteins but serves to regulate gene activity. Furthermore, scientists have identified approximately 4 million regulatory sites where proteins bind to DNA to control gene expression.
Gene expression refers to the process by which information from a gene is used to create proteins. Not every cell expresses the same proteins despite all of them having the same genes. This is because each cell type expresses a different subset of genes to fulfill its specific functions. In humans, with an estimated 20,000 to 25,000 genes, only about 1 to 2 percent of the genome codes directly for proteins. The other 98 to 99 percent encompasses non-coding DNA which includes regulatory elements that control gene expression.
Regulatory DNA sequences are essential because they determine when, where, and how much of a protein should be produced, which is crucial for the proper functioning of cells and the organism as a whole. The complexity of gene expression regulation is integral to the diversity of cell types in a multicellular organism and proper regulation is vital for health, with dysregulation potentially leading to diseases, including cancer.