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Global Population in Genetic Studies

THE IMPORTANCE OF STUDYING MANY POPULATIONS IN GENETIC RESEARCH

  • Humans share nearly all of their genomes (~99%) with each other.
  • Most of the genetic contributors to disease are also shared.
  • Research studies are identifying genetic variants associated with psychiatric and substance use disorders.
  • Research studies are identifying genetic variants associated with psychiatric and substance use disorders.
  • To identify genes that contribute to risk of these and other disorders, it is important to include many individuals with different ancestries. This increases our ability to identify the variants that are in common and those that differ, which will lead to better understanding of the biology of health and diseases for all humankind and allow for precision medicine.
  • Self-identified race and ethnicity are social categories that are not based on genetics and are defined differently in different places and at different times in history. They reflect a particular society’s views at a given time. See Box 1 from Peterson et al., 2019, for information on self-identified race, ethnicity, and genetic ancestry.
  • Recommendations for carrying out genetic association studies in more 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 see the resources listed below.

FAQs

  1. How does increasing genetic diversity improve research studies?
    Genetic diversity allows researchers to explore a wider range of human genetic variation. Studying individuals from diverse backgrounds improves our ability to understand disease mechanisms, identify risk factors, and develop treatments that are relevant across populations.

  2. If race and ethnicity are social constructs, why include diverse populations in genomics research?
    While race and ethnicity are not genetic categories, they often correlate with environmental exposures and social determinants of health, which can influence disease risk and outcomes. Including diverse populations helps researchers better understand how genetics interacts with environment and context.

  3. Can self-reported race or ethnicity be used as a proxy for genetic background?
    Self-identified race or ethnicity does not consistently reflect genetic ancestry. These categories may include individuals with a wide range of genetic backgrounds and should not be used as substitutes for genetic data.

  4. Would it be more accurate to use genetic ancestry instead of race or ethnicity?
    Each measure—self-identified race, ethnicity, and genetic ancestry—provides distinct and context-dependent information. None should be used as a wholesale replacement for the others. In research, their use should be clearly defined and justified.

  5. Why is race sometimes used as a variable in research if it is not genetic?
    Race can correlate with historical, social, and environmental factors that impact health outcomes. While not a genetic variable, it can offer important contextual information in specific research settings, especially when considering disparities in health outcomes.

  6. Why do direct-to-consumer (DTC) ancestry estimates change over time?
    Genetic ancestry estimates are relative and depend on comparisons with reference populations. As DTC companies expand their databases and improve methodologies, ancestry reports may be updated to reflect new information.

  7. What measures of diversity are important in research and clinical care?
    The relevance of diversity measures depends on the context. Self-identified race, ethnicity, and genetic ancestry are all under active investigation. Their use should be based on scientific rationale, supported by evidence, and clearly explained in the research or clinical setting.

  8. How does diversity among researchers impact diversity in research participation?
    Diverse research teams have been shown to produce more innovative and accurate results. Increasing diversity within the scientific workforce may also help build trust with participants and lead to broader and more inclusive participation in studies.

  9. What is the Psychiatric Genomics Consortium doing to support diversity?
    The Psychiatric Genomics Consortium (PGC) has committed to increasing ancestral diversity in its studies. A dedicated Cross-Population Working Group has been formed to support these goals through collaboration, outreach, and development of new methodologies.

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Resources

Additional Reading

  • 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

Methods

  • 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

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