232W Poster - Population Genetics
Wednesday June 08, 8:30 PM - 9:15 PM

Authors:
Ujani Hazra; Joseph Lachance

Affiliation: Georgia Institute of Technology

Keywords:
Natural selection

Background and objectives
Health disparities are due to a range of socioeconomic and biological causes, and many common diseases have a genetic basis. Divergent evolutionary histories cause allele frequencies at disease-associated loci to differ across global populations. To what extent are differences in disease risks due to natural selection?

Methodology
Examining a panel of nine global populations, we identified which of the 20 most common causes of death have the largest health disparities. Polygenic risk scores were computed and compared for 11 common diseases for the same nine populations. We then used PolyGraph to test whether differences in disease risk can be attributed to polygenic adaptation. Finally, we compared human development index statistics and polygenic risk scores to mortality rates for each population.

Results
Among common causes of death, HIV/AIDS and tuberculosis exhibited the greatest disparities in mortality rates. Focusing on common polygenic diseases, we found that genetic predictions of disease risk varied across global populations (including elevated risks of lung cancer in Europeans). However, polygenic adaptation tests largely yielded negative results when applied to common diseases. Our analyses revealed that natural selection was not a major cause of differences in disease risks across global populations. We also found that correlations between mortality rates and human development index statistics were stronger than correlations between mortality rates and polygenic predictions of disease risks.

Conclusions and implications
Although evolutionary history contributes to differences in disease risks, health disparities are largely due to socioeconomic and other environmental factors.