http://www.nytimes.com/2008/04/29/health/research/29heart.html?_r=1&ref=health&oref=login

This article from the New York Times titled “Genes Explain Race Disparity in Response to a Heart Drug” explains why some heart patients experience no improvement in their condition when taking beta blockers. As it turns out, there is a certain kind of gene variant in up to 40% of blacks and up to 2% whites that tend to make patients nonresponsive to the beta blocking drugs used for patients with heart troubles. For those with this altered gene, it is possible that in the future they will be spared taking beta blocking drugs because it is unclear that there would be any benefits yielded from taking the drug. Because often times patients with heart problems take myriad types of drugs, eliminating one drug that’s necessary to take can be, as the article discusses, a huge benefit for the patient.

The concepts in this article are tied to what we have been recently learning in class about network spreading. Sometime in the past, probably (as the article implies) due to some kind of natural selection, a few people produced this altered gene for the first time in history. Thus, if you consider this different gene the start of an epidemic, the epidemic has gone through a branching process. The changed gene had to have begun with just one person. Through reproduction, this altered gene spread through a network of people. For each generation after the initial start, there is some probability p that any given descendent has this altered gene. Considering the statistics the article mentioned, the probability that blacks have the altered gene is higher than the probability that whites have it, but both have a chance. If you take someone who has this altered gene today and look back through their family tree, you could trace the path of the altered gene through a network of people. Also, it possible that some people today have parents with the altered gene, but this does not mean that they necessarily have the altered gene themselves. Gaining this changed gene is not a conscious decision on anyone’s part; it is a matter left up to reproduction. And, finally, because this altered gene proves to be an advantage when dealing with heart trouble, it is also possible that over a very long time period (and on a very small scale), natural selection has been kinder to those in the human network who have this gene.