For thousands of years, our immune systems evolved to fight off assaults from the local threats they encountered. We know that ancestral differences have left their mark in our genomes, but researchers are still investigating how that affects our lives today. In a new PLOS Genetics study, Christine Ambrosone of Roswell Park Comprehensive Cancer Center, U.S., and colleagues examined how genetic differences between women with African and European ancestry affect their immune systems.
The researchers analyzed blood samples from 914 women with African ancestry and 855 women with European ancestry for markers of inflammation and identified significant population differences in seven markers. They also used genetic data to identify a genetic variant, the Duffy-null allele, that occurred primarily in people with African ancestry. The variant is involved in recruiting white blood cells to sites of inflammation, and previous studies suggest it may have evolved to protect African individuals from contracting malaria, which is more prevalent in Africa than in Europe.
Since many cancers and chronic diseases involve inflammation, such immune differences between people with European and African ancestry may have important implications for health.
Co-author Song Yao notes: “These findings indicate that evolutionary adaptation many thousands of years ago shaped our immune systems, and may still have considerable influences on immune function today.”
Research Article: Yao S, Hong C-C, Ruiz-Narváez EA, Evans SS, Zhu Q, Schaefer BA, et al. (2018) Genetic ancestry and population differences in levels of inflammatory cytokines in women: Role for evolutionary selection and environmental factors. PLoS Genet 14(6): e1007368. https://doi.org/10.1371/journal.pgen.1007368
Image Credit: National Institute of Allergy and Infectious Diseases, NIH, Flickr, CC0