SCIENCE Questions: Why Do Humans Have So Few Genes?

"Why Do Humans Have So Few Genes?" is one of the top 25 questions from the 125th anniversary issue of Science magazine [Science, July 1, 2005]. The complete reference is ...

Pennisi, Elizabeth (2005) Why Do Humans Have So Few Genes? Science 309: 80. [Text] [PDF]

Elizabeth Pennisi is a news writer for Science magazine. She has been publishing articles there for at least ten years. She had previously written about genes and genomes, including earlier articles about the number of genes in the human genome.

Pennisi begins with the usual mythology about how surprised scientist were to discover that humans had fewer than 30,000 genes [see Facts and Myths Concerning the Historical Estimates of the Number of Genes in the Human Genome]. She continues by using most of the standard excuses for the Deflated Ego Problem [The Deflated Ego Problem].

That big surprise reinforced a growing realization among geneticists: Our genomes and those of other mammals are far more flexible and complicated than they once seemed. The old notion of one gene/one protein has gone by the board: It is now clear that many genes can make more than one protein. Regulatory proteins, RNA, noncoding bits of DNA, even chemical and structural alterations of the genome itself control how, where, and when genes are expressed. Figuring out how all these elements work together to choreograph gene expression is one of the central challenges facing biologists. [Numbers 1,2,5,6,7]

It's downhill from then on. Pennisi goes on to briefly describe the leading contenders for solving the imaginary problem. Not once does she mention that these have all been challenged in the scientific literature and not once does she mention that they are not specific to humans even though they must be if they're going to get you out of the pickle.

Is this one of the "right" questions that I talked about earlier? [SCIENCE Questions: Asking the Right Question] Nope. Not even close. In fact, it's a very "wrong" question that reflects an ignorance of the scientific literature and a profound misunderstanding of evolution, developmental biology, and gene expression. Humans have exactly the number of genes that we expect. They don't need to have many more genes than fruit flies or worms because a small number of unique genes are all that's required to make significant differences in development. They don't need to have special complexity mechanisms to "explain" anything because there's nothing that needs explaining. Human genes are fundamantally the same as those in Drosophila melanogaster (fruit fly), Caenorhabditis elegans (nematode worm), and Arabidopsis thaliana (a small flowering plant).

This "top 25 question" illustrates exactly the problem that I alluded to earlier. You don't recognize the important questions in science by polling science writers and editors. The "right" questions are the ones being asked on the frontiers by the creative experts who are thinking outside the box. This is an "inside the box" question and very few of those ever turn out to be important.

The right question would have been "Why Were You Surprised?"