If there were a ranking of factors that unite individuals around the world, DNA would undoubtedly be at the top: 99.9% of human DNA sequences are identical to each other.
The Austrian monk and scientist Gregor Johann Mendel (1822 – 1884) was the first to suggest that certain “invisible factors” were responsible for various human characteristics. It is now known that such factors are genes, composed of deoxyribonucleic acid, or DNA.
These acid molecules give genetic instructions to living things. But if humans share so much of the same genetic material, why is diversity important in the context of their sequencing?
To understand this, one must shift the focus to the 0.1% difference between the DNA sequences. This apparently small difference stems from the variations that exist between the 3 billion base pairs (or nucleotides) that make up the human genome.
All the characteristics that distinguish humans from each other, including height and eye or hair color, are due to these variations. But it goes further: Over the years, scientists have discovered that these variations can also provide vital information about an individual or population’s risk of developing a specific disease.
Thus, risk assessment of genetic data can be used to design a health strategy tailored to the individual or region.
Genetics and disease risk assessment
In medical consultations, it is common for the patient to have to fill out forms about the health history of their parents and family members. If one of the parents is diabetic, for example, it is recommended that the child stays away from sweets and processed sugars.
While the transfer of heart disease, cancer and diabetes between generations is best known, there are many other diseases that can be genetically inherited.
For example, sickle cell anemia is known to occur when two abnormal copies of the gene that makes hemoglobin (a protein in red blood cells) are inherited, one from each parent.
In recent decades, genetic research has advanced to the point where scientists have been able to isolate the genes responsible for many diseases. But here’s the problem: science is aware of this correlation between genes and diseases applied to a very narrow population.
Eurocentric data
Sarah Tishkoff, a geneticist and evolutionary biologist at the University of Pennsylvania in the United States, is one of many scientists pushing for more diverse genomic datasets.
It is problematic, for example, if a “study focused on individuals of European descent identifies genetic variants associated with risk of heart disease or diabetes, and uses that information to predict disease risk in patients not included in the original study.”
“We know from experience that this prediction of disease risk does not work well when applied to individuals of different ancestry, particularly if they are of African descent,” explains Tishkoff.
Historically, those who provide their DNA for genomic research are predominantly of European descent, “which creates gaps in knowledge about genomes in the rest of the world,” reports the National Human Genome Research Institute (NHGRI), in USA.
According to the institution, 87% of all available genome data in the world are of European descent, followed by 10% of Asians and 2% of Africans.
As a result, the potential benefits of genetic research, which includes early diagnosis and treatment of various diseases, may not benefit underrepresented populations.
Lack of equity in treatment
The problem does not end with the assessment of disease risk. It also leads to inequality in medical care, says Jan Witkowski, a professor at the Graduate School of Biological Sciences at Cold Spring Harbor Laboratory in New York State.
“Let’s say there are two groups, A and B, which are very different. The knowledge and information you learn about group A may not apply to group B. Imagine developing medical treatments for everyone, based only on information from group A.” . It won’t work on group B.”
By including diverse populations in genomic studies, researchers can identify genomic variants associated with various health settings, both at the individual and population levels.
According to the NHGRI institute, however, diversifying participants in genomic research is expensive and requires the establishment of long-term relationships of trust and respect between communities and researchers.
