This article, by Fotios Drenos and Thomas B. L. Kirkwood, both of the Institute for Ageing and Health at Newcastle University, Newcastle Upon Tyne, Tyne, United Kingdom, that appeared on March 31, 2010, in the online journal PloS One, uses computer simulation to show that the effects of natural selection on genes affecting health in old age can be significant. Below is the abstract from the article. To read the complete article, please see the following URL: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0010022.
It is often claimed that genes affecting health in old age, such as cardiovascular and Alzheimer diseases, are beyond the reach of natural selection. We show in a simulation study based on known genetic (apolipoprotein E) and non-genetic risk factors (gender, diet, smoking, alcohol, exercise) that, because there is a statistical distribution of ages at which these genes exert their influence on morbidity and mortality, the effects of selection are in fact non-negligible. A gradual increase with each generation of the ε2 and ε3 alleles of the gene at the expense of the ε4 allele was predicted from the model. The ε2 allele frequency was found to increase slightly more rapidly than that for ε3, although there was no statistically significant difference between the two. Our result may explain the recent evolutionary history of the epsilon 2, 3 and 4 alleles of the apolipoprotein E gene and has wider relevance for genes affecting human longevity.