Diversity in Genomic Research
Diversity among genomics research participants is essential for improving the health of everyone.
The Big Picture
-
Human DNA sequences (that is, our genomes) are more than 99.9% identical among people.
-
The 0.1% genomic differences come from variations among the nearly 3 billion bases (or “letters”) in our DNA; sometimes these variations can influence our chances of developing a disease.
-
So far, most people who have given permission for their DNA to be used for research are from European ancestry, making many populations from across the globe underrepresented in genomics research.
-
The National Human Genome Research Institute (NHGRI) is working to enhance the diversity of people who participate in genomics research, thereby improving our knowledge of human genomic variation and genomic information for all populations.
What makes human genomes diverse?
While humans are similar in most ways, our biological processes make each of us unique. Many aspects of those processes are encoded in our DNA, which is based on the sequence of the four letters of life — A, C, G, and T. The dissimilarities among human genomes, referred to as variants, come from differences in our DNA sequences.
The human genome is more than 3 billion letters long, which means that a variant could reside at any place among those letters. These variants occur at different frequencies across different human populations; some are rare and unique to specific families, while others are common and found across populations.
Genomes from distinct populations differ due to multiple factors, including who people decide to reproduce with, as well as human migration patterns. Also, in specific populations, certain variants became widespread as they provided an advantage that helped them adapt to environmental changes.
Factors displayed in the graphic include: reproduction, migration and random fluctuations.
Why should researchers collect genomic data from diverse populations?
Based on work completed before and after the Human Genome Project, researchers found that the genome sequences of human populations have changed significantly over 250,000 years of our species’ expansion and migration across the Earth.
Even with the high degree of similarity between any two human genomes, enough differences exist that it is not appropriate to use a single, or even a few, genomes to represent the world’s populations. This highlights that the original human genome reference sequence, produced by the Human Genome Project and based on just a handful of research participants, was just the starting point for human genomics.
To address this limitation, efforts are underway to create human reference genome sequences that better represent diverse populations. NHGRI funds the Human Pangenome Reference Program, which is generating a collection of reference genome sequences that better represent human diversity.
The following graphic displays ancestry populations included in large-scale genomic studies by percentages (from highest to lowest): 78% European; 10% Asian; 8.5% Unreported; 2% African; 1% Hispanic; and 0.5% Other Countries
The percentage of ancestry populations included in large-scale genomic studies is overwhelmingly European.
How does studying diverse human genomes improve health outcomes?
Every human has some baseline genetic risk of developing a given disease. Extensive research has been performed to both understand and learn how to respond to these risks. In some cases, the same variant consistently causes a disease (e.g., Huntington's disease and cystic fibrosis), but this might not be the case for more complex diseases (e.g., coronary artery disease, obesity, cancer and Alzheimer’s disease).
By including populations that reflect the full diversity of human populations in genomic studies, researchers can identify genomic variants associated with various health outcomes at the individual and population levels. This way, researchers can better define a person's risk of developing a specific disease and design a clinical management strategy that is tailored to the individual. In addition, they can pursue genomic medicine strategies that benefit specific populations.
Why has enhancing diversity in genomics research been a difficult task?
Increasing the representation of diverse participants in genomics research requires an investment of both resources and time to intentionally establish trusting and respectful long-term relationships between communities and researchers. To ensure that genomics research is both equitable and inclusive, it is crucial for the genomics research workforce to reflect a similar diversity as the communities that the research is intended to serve.
In the past, both inaccessible and insufficient communication left some research participants unclear about the benefits of their participation and how their data would be used after the studies concluded. To overcome this, researchers must seek to understand people’s reasons for not participating in genomic studies and to communicate with participants in a more accessible manner. This can take additional time, effort and resources, which may discourage some researchers from including these important, diverse populations in their studies. However, such exclusion can lead to notable gaps in scientific understanding and potentially reenforce existing disparities in genomics research.
Companion Fact Sheet
Last updated: May 9, 2023