How evolutionary principles improve the understanding of human health and disease

One of the main differences across geography between different groups of people is their immune system and their resistance to disease. These types of differences lead to the question of whether these phenotypic changes between people is allelic or due to natural human plasticity. Epigenetics has confused this question: it now appears that there exist predispositions to certain diseases due to the inheritance of epigenetic markers that were added in very recent history to individuals faced with a certain situation in a certain time. These markers affect how children in very different environments may respond to stimuli despite the fact that these changes are not in the coding region of DNA and therefore will not be found by any SNP chip. Gluckman et al. argues that doctors, in looking to better understand diseases, will have to look at demographics, evolutionary biases, life histories, and family histories to begin to pull together a comprehensive theory of disease.