The Importance of Global Population Diversity in Genetic Research
- Most of the genetic contributors to disease are shared across human populations.
- Diversity in human population genetics refers to differences in the DNA that occur within and across populations. There are more genetic differences within broad continental populations than between them.
- Self-identified race and ethnicity are social categories that are not based on genetics. See Box 1 from Peterson et al., 2019 for information on self-identified race, ethnicity, and genetic ancestry.
- Research studies are identifying genetic variants associated with psychiatric and substance use disorders. These studies have included mostly people of European ancestry and do not reflect global population diversity.
- In addition to the ethical imperative, including more people of diverse ancestry in genetics research will lead to better understanding of the biology of health and diseases for all humankind.
- Findings to date mostly reflect European ancestry individuals and are less informative for people of other ancestral backgrounds, which hinders the application of precision medicine to a majority of the world’s population.
- Efforts are underway to address persistent barriers to diversity in genetics research, and much more needs to be done in order for researchers and research participants to be representative of global population diversity.
- Recommendations for carrying out genetic association studies in diverse ancestral populations are detailed in Peterson et al., 2019.
- Researchers interested in learning more about how to foster and support inclusive research environments and professional networks should go to see the resources listed below.
- How will increasing diversity improve our studies?
Genetic diversity is the presence of differences in genome variation across individuals and populations. Including genetically diverse populations in research lets us see a larger portion of human variation and is important for investigators to understand pathways to disease and recovery for all.
- If “race” and “ethnicity” are social constructs (as opposed to biological factors) why does there need to be diversity in genomics research?
Social and cultural diversity are important for genetics research because environmental factors play a large role in how and when disorders arise. Unfortunately, most societies have structural and institutionalized inequities that privilege certain groups over others. This leads to group-level differences in environmental exposures and outcomes and may limit the applicability of some research findings in different contexts or populations.
- Can self-reported race and ethnicity of study participants be used as a proxy for genetic background?
Using self-reported race and/or ethnicity of study participants as a proxy for genetic background is inaccurate because genetic diversity is greater within racial and ethnic groups than between them. Self-defined race/ethnicity can contain a range of genetic ancestries.
- Given the dynamic and unreliable nature of self-identified ‘race’ and ‘ethnicity’, would it be more accurate to simply replace these concepts with genetic ancestry?
Each of these measures of diversity represents different information, so none of them can or should be used as a replacement for any other. Race and ethnicity are often used as proxies for environmental factors.
- Race has been used as a variable in research; how can you explain this if race is not genetic?
Even though race is not genetic, there can be overlap between race and global ancestries. The environment, including socio-economic disparities and racism, influences many of the traits we study and has a differential impact on subgroups defined within societies as ‘race’ or ‘ethnicity’. Therefore, including them as a variable can be important.
- Why do ancestry estimates from direct-to-consumer (DTC) companies seem to change over time?
Ancestry is often misunderstood to be an objective, fixed measure of geographic location of one’s ancestors. However, ancestry (like other measures of diversity) is relative. Just ~200,000 years ago, the common ancestors of all modern humans lived on the continent of Africa. Reported ancestry percentages measure similarity between an individual’s DNA and DNA from others that have lived in specific places in the world for recent generations. These percentages will continue to be updated as more individuals from more locations are included.
- What measures of diversity are important and for what purposes?
Self-identified race and ethnicity, and/or genetic ancestry are under active investigation to determine whether (and if so, how) they are relevant. Whatever measures of diversity are used, whether for research or clinical care, the decision to use such measures needs to be evidence-based, well-reasoned, and openly justified for the relevant purpose or context.
- How does the lack of diversity among genetics and genomics researchers influence diversity among study participants?
Research has shown that more diverse teams produce more innovative and accurate findings. Diversity in the genomics workforce may also increase diversity among research participants and more trust between researchers and the populations studied, which is highly beneficial.
- What is the Psychiatric Genomics Consortium doing to address these issues?
Increasing the ancestral diversity of PGC meta-analyses through outreach and novel methods is one of the aims of the next 5 years. The Psychiatric Genomics Consortium Cross-Population working group has been formed to assist these efforts.
- Hurtado S, White-Lewis D, Norris K. Advancing inclusive science and systemic change: the convergence of national aims and institutional goals in implementing and assessing biomedical science training. BMC Proc. 2017 Dec 4;11(Suppl 12):17. doi: 10.1186/s12919-017-0086-5. PMID: 31851727; PMCID: PMC5773897.
- Talking About Race. (United States African American Museum)
- Popejoy AB, Fullerton SM. Genomics is failing on diversity. Nature. 2016;538(7624):161-164. doi:10.1038/538161a
- Peterson RE, Kuchenbaecker K, Walters RK, et al. Genome-wide Association Studies in Ancestrally Diverse Populations: Opportunities, Methods, Pitfalls, and Recommendations. Cell. 2019;179(3):589-603. doi:10.1016/j.cell.2019.08.051 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6939869
- Martin AR, Kanai M, Kamatani Y, et al. Current clinical use of polygenic scores will risk exacerbating health disparities. Nat Genet. 2019 April ; 51(4): 584–591. doi:10.1038/s41588-019-0379-x
Mentoring & Research Network
- National Research Mentoring Network (https://nrmnet.net; US)
- Building Infrastructure Leading to Diversity (BUILD) Initiative (https://www.nigms.nih.gov/training/dpc/pages/build.aspx)
- Clinical and Translational Science Network (CTSciNet) https://www.aaas.org/news/aaas-and-partners-debut-new-online-networks-clinical-and-minority-scientists
- Diversity Program Consortium (DPC) https://www.diversityprogramconsortium.org/pages
- EU Platform of Diversity Charters.The Platform offers a place for existing European Diversity Charters to exchange and share experience and good practices.
- Building the future of health research. A consensus document of the H2020 Scientific Panel for Health.
- Increasing Diversity in the Biomedical Research Workforce: Actions for Improving Evidence
- Collection of resources compiled by the North American Society for Pediatric Gastroenterology, Hepatology & Nutrition