The estimated number of DNA-binding transcription factors in the human genome falls in which range?

The estimated number of DNA-binding transcription factors in the human genome falls in which range?

• A. Approximately 1,600 to 2,000.
• B. Approximately 100 to 200.
• C. Approximately 5,000 to 6,000.
• D. Approximately 20,000 to 25,000.

Answer: (A)

DNA-binding transcription factors are the proteins that recognize specific DNA sequences to regulate gene expression. In humans, the number of these regulators is large but not endless, falling in the low-thousands. The best estimate is about 1,600 to 2,000 distinct transcription factor genes. This range reflects that many genes code for TFs because precise control of expression across tissues and development requires a diverse set of regulators, including many related family members with shared DNA-binding domains (like zinc fingers, homeobox, and basic helix-loop-helix families). It’s far more than a couple hundred because each family has numerous paralogs, yet it’s not tens of thousands because not every gene encodes a DNA-binding regulator. So, around sixteen hundred to two thousand TFs fits what we know about human gene regulation. The other ranges would underrepresent the diversity of TFs or vastly overstate how many genes act directly as transcription factors.

DNA-binding transcription factors are the proteins that recognize specific DNA sequences to regulate gene expression. In humans, the number of these regulators is large but not endless, falling in the low-thousands. The best estimate is about 1,600 to 2,000 distinct transcription factor genes. This range reflects that many genes code for TFs because precise control of expression across tissues and development requires a diverse set of regulators, including many related family members with shared DNA-binding domains (like zinc fingers, homeobox, and basic helix-loop-helix families). It’s far more than a couple hundred because each family has numerous paralogs, yet it’s not tens of thousands because not every gene encodes a DNA-binding regulator. So, around sixteen hundred to two thousand TFs fits what we know about human gene regulation. The other ranges would underrepresent the diversity of TFs or vastly overstate how many genes act directly as transcription factors.