It's not exactly a secret that we are very skeptical about what we believe is the hyper-geneticizing of life, both in terms of what we think are simplistic evolutionary just-so scenarios, and raising of hopes for simplistic predictability between your genome and everything about you.
But our traits have to come from somewhere, and manifestly much of this is inherited and just as clearly much of this involves genes. Not only do genes (here we use the term broadly for DNA-based functions, not just protein coding) carry out biological function, but variation in genes is causally associated with variation in function. And, of course, our genomes evolved by processes that, yes, included natural selection.
Our point has consistently (we hope) been that evolutionary processes generally lead to more complex, multigenic, less causally deterministic traits than is the current working model (or hyperbole). On the other hand, life is a spectrum of genetic causal effects. Most are small, and the responsible variants rare and geographically local, and most traits are due to the aggregate effects of many genes. But the spectrum has its more strongly causal segment as well. Some traits really are genetic in all the usual senses of the term. Included among them are many diseases, usually congenital, severe, and relatively rare in the population.
For these really genetic traits, one or a few genes are responsible, and for associated diseases perhaps specific variants in those genes. These present completely appropriate (socially responsible as opposed to eugenic) targets for all sorts of intervention or preventive measures. Here, we enter the realm of clear causation and hence focused technological approaches. Simple causation of this kind is reasonably thought to be vulnerable to highly targeted gene-based pharmacology (serving as 'druggable' targets). And these traits also are appropriate for gene therapy, that is, to try to replace a defective gene with a healthily functioning one.
Now organisms don't like to be messed with, and often tend to resist, and individual defective cells may be located in inaccessible parts of the body, and so on. But one should never bet against technology when it has, as in this case, an appropriate problem to solve. For that reason, we have written and said elsewhere that one should not be too impatient at failures of Pharma or gene gene technology to solve these problems. They are tough problems! Still, don't bet against technology.
And here's a story about gene therapy that seems to be working. The story, in yesterday's NYT, reports some success in treating Hemophilia B, a disease caused by mutations in the gene for Factor IX, an X-linked gene (so that the disease is almost exclusively found in males), that lead blood not to clot, because the missing protein is needed in the clotting interactions. Hemophilia has storied associations with European royalty and hemophiliacs were tragically affected by needing transfusions that they received from donors affected with HIV, until such testing and screening became effective. But if there is a single defective gene, an obvious thing to try is to develop a modified virus as a vector (carrier) of a healthy gene. The virus is structured so that in a particular target cell (in this case, the liver) it will express the normal human gene, but will not be harmful itself. In the trials that have just been reported, the newly expressed exogenously introduced gene produced the missing clotting factor, secreted it into the blood stream, and the patient's blood then could clot more or less normally.
The effect was temporary (because of cell turnover in the patient), and not 100% in all tested individuals. And because the patient's body resists foreign invaders--like viruses!--it developed antibodies to the injected vector, so that the treatment couldn't be repeated (the virus would be destroyed before it could get into the host's cells). So this trial is only a first step. But it showed that the idea can work, even if various tricks will have to be developed to get around or to suppress immune resistance to the treatment.
If the problem is simple enough, as some genetic problems are, then solutions can be expected, even if not always immediately. In genetics as in electronics, never bet against technology.