Nicholas Wade Writes about Genomes and Evolution

 
His fellow science writers often think that Nicholas Wade is among the best of their ilk. Wade writes for the New York Times and his latest article is: A Decade Later, Genetic Map Yields Few New Cures. A couple of paragraphs from that article deserve some kind of award.

But while 10 years of the genome may have produced little for medicine, the story for basic science has been quite different. Research on the genome has transformed biology, producing a steady string of surprises. First was the discovery that the number of human genes is astonishingly small compared with those of lower animals like the laboratory roundworm and fruit fly. The barely visible roundworm needs 20,000 genes that make proteins, the working parts of cells, whereas humans, apparently so much higher on the evolutionary scale, seem to have only 21,000 protein-coding genes.

The slowly emerging explanation is that humans and other animals have much the same set of protein-coding genes, but the human set is regulated in a much more complicated way, through elaborate use of DNA’s companion molecule, RNA.

Thanks to Jonathan Eisen at The Tree of Life, Nicholas Wade can now add the "Twisted Tree of Life Award" to his many others [Twisted tree of life award #5: Nicholas Wade & use of higher, lower, ladders, etc].

You see, Wade makes one of the most fundamental errors of evolutionary thinking when he writes about "higher" and "lower" on the "evolutionary scale."

There are two other flaws in his quoted excerpt. First, it did not come as a big surprise to all scientists that humans had about the same number of genes as other animals. That's a myth based on overemphasizing the opinions of some people and underemphasizing the opinions of the experts [Facts and Myths Concerning the Historical Estimates of the Number of Genes in the Human Genome]. This is part of what I call The Deflated Ego Problem and it's not endemic. It can be cured by reason.

Second, the explanations for similar numbers of genes in animals come from genetics and developmental biology over the past fifty years. It may have been "slowly emerging" back when I first started teaching but it's now fully emerged and has been for twenty years. Long before the human genome was sequenced we knew that major morphological changes could be caused by small mutations in regulatory sequences. During the 1980s and 1990s it became apparent that animals such as Drosohila and humans shared many important development genes¹ and even more of the genes involved in basic metabolism. This was not a surprise.

It may be true that RNA places a much more important role in regulating gene expression than we thought. The jury is still out on that one. However, even if RNA is part of the regulation picture that fact does not change the basic principle that molecular biologist developed over the past thirty years; namely, that the same basic gene set is just regulated differently in different animals. This is the contribution of Evo-Devo.

There's one other logical flaw made by those with deflated egos. What they're looking for is some specific mechanism that explains the marvelous complexity of humans relative to the "lowly" fruit fly or nematode. What they need in order to satisfy this longing is a mechanism that we have and they don't. As far as I know, there isn't (hardly) anyone who claims that regulatory RNAs have only evolved in humans. The genome sequences of all animals is pointing in the same direction. If there are abundant regulatory RNAs then there are lots in nematodes and fruit flies as well. It's not going to solve the pseudoproblem that Nicholas Wade imagines.

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1. Perhaps you've heard of homeotic genes and HOX genes?