Natural selection led to racial differences in susceptibility to disease, Part I

Here's a figure from a new study that reviews research on racial differences in immune system response. Notice how the regions with the highest abundance of pathogens (disease-causing microorganisms) are the northern half of South America, central sub-Saharan Africa (SSA), and southeast Asia.

The graph also traces important moves humans have made over the past 65,000 years, and the right panel shows that people with European ancestry suffer from high rates of death from Parkinson's and Alzheimer's, while those with SSA ancestry experience a high incidence of mortality from cardiovascular disease, surgical complications, meningitis, diabetes, septicemia (blood poisoning), kidney inflammation, perinatal death, asthma, childbirth, and HIV.

In the next post, I'll summarize the evidence presented in the study that immune system genes show signs of evolutionary adaptation to the different pathogen environments that races have lived in.