What percent of all human genes do odor receptor genes represent?

What percent of all human genes do odor receptor genes represent?

• A. About 0.1%
• B. About 5%
• C. About 10%
• D. About 1%

Answer: (D)

Odor receptor genes form a very large gene family, but they still make up only a small fraction of all human genes. In humans there are roughly a few hundred functional odorant receptor genes, and the total number of human protein-coding genes is on the order of twenty thousand. Doing a rough ratio gives about 400 out of 20,000, which is around 2%, and estimates can vary slightly depending on how genes and pseudogenes are counted. When rounded to a simple percent, this falls closest to about one percent, making that option the best match.

Odor receptor genes form a very large gene family, but they still make up only a small fraction of all human genes. In humans there are roughly a few hundred functional odorant receptor genes, and the total number of human protein-coding genes is on the order of twenty thousand. Doing a rough ratio gives about 400 out of 20,000, which is around 2%, and estimates can vary slightly depending on how genes and pseudogenes are counted. When rounded to a simple percent, this falls closest to about one percent, making that option the best match.