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DNA Tests’ Reliability on the Basis of Diversity

Written by Adanur Nas


Humans’ genomes are subject to differ from each other by 0.1%. This percent has been revealed and substantiated by various of research conducted by professors. Although the fraction is only 0.1%, it is subject to decrease if there is a factor of being related to someone identical at the level of being in a same family or ethnicity. People tend to think that even though two random people are not identical, twins must be identical. The claim has been confuted by the scientists at the University of Alabama at Birmingham and universities in Sweden and the Netherlands. The studies showed that even twins were not identical but rather sharing pretty similar genomes [4]. However, these research’s outcomes have always been a topic of debate as people can receive different outcomes based on every different DNA companies [2].


Still being a hot topic of debates, those tests’ reliabilities fail to determine one individual’s ethnicity as they commonly originate from living individuals’ genomes. Furthermore, the results depend on the company and its customers. As Georgine Lawton mentions in her blog, the DNA testing company 23andMe has mostly American customers, while another DNA testing company AncestryDNA has British and Australian customers [1]. The fact that they have certain customer types sparked the curiosity of individuals who took these DNA tests since the diversity was not that much as they expected from them. The analysis that took place in 2009 showed that the participants in GWAS (Genome-Wide Association Studies)’s research were from European ancestry by 96%. However, the rate had been decreased by the year 2016 to 80% as more people from mainly Asia and Africa participated in the research [5]. Notwithstanding the research had been diversified, by the year 2018, they were still not accurate for non-European people as much as they were accurate for European people [8]. Even after from the year 2018, the things have not changed substantially, and people’s doubts remained same.


The DNA test is one way to determine diseases in human genomes. Nonetheless, these tests can provide some kind of an unreliability despite of its results, since the tests are contingent upon the same companies as mentioned before. To understand the underlying reason, it is said that the companies are not unreliable companies because one of them has had an approval by FDA (U.S. Food and Drug Administration) since 2017. However, its unreliability may underlie for individuals who do not have European ancestry dominantly [9]. Moreover, there have always been diseases that varied from each other according to their point of origin. One disease rather affected the people of Asia, whereas the other one affected the people of Africa. If that is the case, how can we trust white-dominated DNA tests? The professors of Cell investigated the problem in it and came up with the result that showed us why we had always needed more diversified DNA tests to examine one individual’s genomes to specify if that person has a risk of a genetical disease or not [6]. This lack of diversity has more disadvantages than advantages to non-European ancestry. To give more specific details for this claim, we can put forward the HBB (Hemoglobin Subunit Beta) gene which is responsible for providing directions to make beta-globin protein. The mutated HBB gene causes Beta Thalassemia. Even though its underlying reason is still a mystery, African-American people are prone to have this disease compared to other races [7]. Apart from its this feature, HBB gene is also known for its capability to affect some of the HBA1C tests which are used for identifying diabetes. The researchers have brough to light the effect of it that the HBA1C tests might result one individual not being prescribed as they need, since their CRP (the protein that helps diagnosing the diseases) level might be below under the diagnostic level that was mostly determined by using African-American people’s DNAs [3].


To sum up, the DNA test’s reliability is a hot topic of debates as plenty of them lack in diversity which results in one individual to (frequently non-Europeans) fail to determine their ancestry. And what is worse, the tests may fail to diagnose the diseases. Even if most of the European people do not face with problems with DNA tests, the more diversified tests should be provided for the individuals of other ethnicities to prevent them from having worsening health conditions.


References:
  1. Lawton, G. (2018, August 11). It made me question my ancestry: does DNA home testing really understand race? Retrieved February 28, 2021, The Guardian https://www.theguardian.com/lifeandstyle/2018/aug/11/question-ancestry-does-dna-testing-really-understand-race

  2. Letzter, R. (2018, November 5). I took 9 different DNA tests and here's what I found. Retrieved February 27, 2021, from Live Science https://www.livescience.com/63997-dna-ancestry-test-results-explained.html

  3. Mapes, D. (2019, June 19). Lack of diversity in genetic research a problem. Retrieved February 28, 2021, from Fred Hutch https://www.fredhutch.org/en/news/center-news/2019/06/lack-diversity-genetic-research-problem.html

  4. 0’Connor, A. (2008, March 11). The Claim: Identical Twins Have Identical DNA. Retrieved February 27, 2021, from The New York Times https://www.nytimes.com/2008/03/11/health/11real.html

  5. Popejoy, A. B., & Fullerton, S. M. (2016). Genomics is failing on diversity. Nature, 538(7624), 161–164. https://doi.org/10.1038/538161av

  6. Sirugo, G., Williams, S., M., Tishkoff, S., A. (2019, March 21). The Missing Diversity in Human Genetic Studies. Retrieved February 28, 2021, from Cell https://www.cell.com/cell/fulltext/S0092-8674(19)30231-4

  7. Solovieff, N., Hartley, S. W., Baldwin, C. T., Klings, E. S., Gladwin, M. T., Taylor, J. G., 6th, Kato, G. J., Farrer, L. A., Steinberg, M. H., & Sebastiani, P. (2011). Ancestry of African Americans with sickle cell disease. Blood cells, molecules & diseases, 47(1), 41–45. https://doi.org/10.1016/j.bcmd.2011.04.002

  8. Weise, E. (2018, December 2). Looking for your roots? For Asians, blacks and Latinos, DNA tests don't tell whole story. Retrieved February 28, 2021, from USA Today https://www.usatoday.com/story/news/2018/12/02/asians-blacks-latinos-genealogical-tests-dont-tell-full-story/2132681002/

  9. (2017, April 6). FDA allows marketing of first direct-to-consumer tests that provide genetic risk information for certain conditions. Retrieved February 28, 2021, from U.S. Food and Drug Administration https://www.fda.gov/news-events/press-announcements/fda-allows-marketing-first-direct-consumer-tests-provide-genetic-risk-information-certain-conditions

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