Complexity_ A Guided Tour - Melanie Mitchell [133]
Genetics has become very complicated indeed. And the implications of all these complications for biology are enormous. In 2003 the Human Genome Project published the entire human genome—that is, the complete sequence of human DNA. Although a tremendous amount was learned from this project, it was less than some had hoped. Some had believed that a complete mapping of human genes would provide a nearly complete understanding of how genetics worked, which genes were responsible for which traits, and that this would guide the way for revolutionary medical discoveries and targeted gene therapies. Although there have been several discoveries of certain genes that are implicated in particular diseases, it has turned out that simply knowing the sequence of DNA is not nearly enough to understand a person’s (or any complex organism’s) unique collection of traits and defects.
One sector that pinned high hopes on the sequencing of genes is the international biotechnology industry. A recent New York Times article reported on the effects that all this newly discovered genetic complexity was having on biotech: “The presumption that genes operate independently has been institutionalized since 1976, when the first biotech company was founded. In fact, it is the economic and regulatory foundation on which the entire biotechnology industry is built.”
The problem is not just that the science underlying genetics is being rapidly revised. A major issue lurking for biotech is the status of gene patents. For decades biotech companies have been patenting particular sequences of human DNA that were believed to “encode a specific functional product.” But as we have seen above, many, if not most, complex traits are not determined by the exact DNA sequence of a particular gene. So are these patents defensible? What if the “functional product” is the result of epigenetic processes acting on the gene or its regulators? Or what if the product requires not only the patented gene but also the genes that regulate it, and the genes that regulate those genes, and so on? And what if those regulatory genes are patented by someone else? Once we leave the world of linear genes and encounter essential nonlinearity, the meaning of these patents becomes very murky and may guarantee the employment of patent lawyers and judges for a long time to come. And patents aren’t the only problem. As the New York Times pointed out, “Evidence of a networked genome shatters the scientific basis for virtually every official risk assessment of today’s commercial biotech products, from genetically engineered crops to pharmaceuticals.”
Not only genetics, but evolutionary theory as a whole has been profoundly challenged by these new genetic discoveries. A prominent example of this is the field of “Evo-Devo.”
Evo-Devo
Evo-Devo is the nickname for “evolutionary developmental biology.” Many people are very excited about this field and its recent discoveries, which are claimed to explain at least three big mysteries of genetics and evolution: (1) Humans have only about 25,000 genes. What is responsible for our complexity? (2) Genetically, humans are very similar to many other species. For example, more than 90% of our DNA is shared with mice and more than 95% with chimps. Why are our bodies so different from those of other animals? (3) Supposing that Stephen Jay Gould and others are correct about punctuated equilibria in evolution, how could big changes in body morphology happen in short periods of evolutionary time?
It has recently been proposed that the answer to these questions lies, at least in part, in the discovery of genetic switches.
The fields of developmental biology and embryology study the processes by which a fertilized single egg cell becomes a viable multibillion-celled living organism. However, the Modern Synthesis’s concern was with genes; in the words of developmental biologist Sean Carroll, it treated developmental biology and embryology