Tweet
Researchers at the National Human Genome Research Institute (NHGRI), a component of the National Institutes of Health, have discovered that the lack of consideration for mixed genetic backgrounds in people with European ancestry might have led to incorrect conclusions in previous genetic research. The study, published in Nature Communications, indicates that the genetic diversity within European populations is more complex than previously thought, and it calls for a reassessment of past genome-wide association studies.
The Complex Tapestry of European Genetics
In their assessment, the NHGRI scientists found that European individuals have a diverse genetic makeup that reflects mixed lineages, contradicting the notion of genetic homogeneity. Dr. Daniel Shriner, the study's senior author, emphasized the nuanced genetic landscape of Europe, stating, "What is clear based on our analysis, is when data from genetic association studies of people of European ancestry are evaluated, researchers should adjust for admixture in the population to uncover true links between genomic variants and traits."
To conduct their study, the team compiled a comprehensive reference panel that included genomic data from 19,000 individuals across 79 European populations and European Americans. This new reference panel captures a breadth of ancestral diversity not represented in previous datasets.
Re-evaluating Genetic Links
A key focus of the research involved the lactase gene, responsible for producing an enzyme that aids in lactose digestion and varies widely across European populations. Upon reanalysis, considering genetic admixture, the scientists discovered that the variant associated with lactose digestion does not affect height or low-density lipoprotein cholesterol levels as previously thought. However, it does influence body mass index.
Dr. Charles Rotimi, the director of the Center for Research on Genomics and Global Health and a senior author, underscored the necessity of recognizing mixed ancestry in genetic research, stating, "The findings of this study highlight the importance of appreciating that the majority of individuals in populations around the world have mixed ancestral backgrounds and that accounting for these complex ancestral backgrounds is critically important in genetic studies and the practice of genomic medicine."
Implications for Future Research and Genomic Medicine
The incorrect associations of certain genetic variants with traits in past studies may have broader implications, potentially impacting the accuracy of polygenic risk scores and the understanding of an individual's response to medications. Dr. Mateus Gouveia, the first author of the study, expressed hope that by considering mixed ancestries in future genomic analyses, the scientific community could improve the predictive power of genetic studies.
The small percentage of genomic variation between individuals can offer insights into genetic ancestry and disease risks. Recognizing accurate genetic associations is crucial for the efficiency and precision of future research, with the potential to enhance genomic medicine.
The NHGRI team has made their reference panel available to the scientific community, providing a valuable resource for ongoing and future research efforts.