Adriana Mercedes
Genetics writing assignment #4
10/12/2021


Benefits of examining diverse populations
Researchers recently performed the world’s largest genetic study of cholesterol levels by taking data and medical information from 201 studies in 35 different countries involving over 1.64 million people. This large amount of data shows the benefits of having a diverse pool to study from and it also improved the ability to identify genes that control cholesterol levels and now researchers are able to predict levels across all different ancestries.
The study of human genetics needed to improve its diversity of research participants so that new information could be learned from different racial and ethnic groups. Most human genetic studies are dominated by European ancestry even though it is one of the smallest populations globally. Elevated cholesterol levels are heritable but also a treatable health trait that can cause atherosclerotic and cardiovascular disease; which is the worlds leading cause of death. Due to blood lipid levels being measured throughout clinical care this metric was studied in large numbers of people from non-European ancestry to find new genes controlling this risk factor and to improve the prediction of disease occurrences across racial and ethnic groups. Researchers studied around 350,000 participants of Hispanic, African, and east/south Asian ancestry all together with around 1.3 million people of European ancestry.
Using that many individual participants lead to the discovery of many DNA variants that influenced the levels of five different lipid levels including low-density lipoprotein cholesterol (LDL-C), which is a known risk factor for heart attacks. After changing the sample size, they found more genetic risk in people of Hispanic and mixed African ancestry than in those of Asian, European, or South Asian ancestry for all ancestries combined. The research found that most almost all of the genetic variation that influenced lipid levels was studied across all populations, even though some variants were observed in only one population — particularly in individuals with African or Hispanic ancestry. The number of genetic variants was approximate the same for all ancestry groups after adjusting for group size. However, the ability to use polygenic risk scores (PRSs) which is a genetic risk measure — to predict LDL-C levels, as well as to find the genetic variants that are most likely to be responsible for biological effects, was markedly improved when the initial study was more diverse.
At the end of this study, their findings were reinforced and the need to conduct larger genetic studies with a more diverse population.

Graham, S. E. et al. The power of genetic diversity in genome-wide association studies of lipids. Nature https://doi.org/10.1038/s41586-021-04064-3 (2021)