Health Science Reviews

by Oliver De Sousa

Research into human genomics is a rapidly advancing field. The completion of the human genome project in 2003 (Zhang et al. 2022) and the subsequent creation of the human reference genome (HRG) was one of the greatest scientific achievements in history. It was this milestone which helped kickstarted humanity into a new era of genomic research.

Our current progress in understanding human genomics has revealed that genomic based studies can provide insight into a variety of medical fields (Omotoso et al. 2022). One such field is the emerging field of Precision Medicine. This field revolves around designing diagnoses and treatments based on individual patients and their unique genomic make-up (König et al. 2017).

This is a wonderful concept: having my medical treatment designed and tailored based on my unique genome.

However…

What if the current genomic data doesn’t equally represent all population groups? In such a scenario, we might expect that treatment plans and their success could become biased towards the overrepresented population groups. Based on current research, this assumption would indeed be correct.

Unfortunately, today we are still fighting the fact that African populations are underrepresented in genomic research. In fact, it is estimated that African populations only represent 2% of all genomic data available (Zhang et al. 2022). This number is astoundingly low when you reflect that Africa is the most genetically diverse continent, harboring 54 countries and over 3000 ethnolinguistic groups (Omotoso et al. 2022).

So, what makes Africa So Genetically Diverse?

Our continent has long been considered epicentre of modern human origin based on fossil and genetic evidence (Zhang et al. 2022). This means that humans have lived longer on this continent than anywhere else (Baker et al. 2017). Our time spent here, in aid with the need to adapt evolutionarily to many infectious diseases and environmental challenges (Baker et al. 2017), has resulted in this immense pool of genetic diversity. A pool which is currently not being used to its full potential, and as a result of this, the residents of this continent are suffering for it. The representation in genomic studies has been dominated by populations hailing from Europe, this concentration of research has created a “Genomic Gap” (Omotoso et al. 2022).

The paper written by Zhang et al. 2022 and titled “Evaluating the promise of inclusion of African ancestry populations in genomics” aims to explore this genetic pool’s diversity and suggest the extent of its full potential.

The paper examines recent genomic literature that includes individuals of African ancestry. Based on these findings, the authors provide a summary and highlight key areas in which the inclusion of African ancestry populations into genomic studies has demonstrated promise and where progress is still required.

I want to on the papers reflections regarding the effect of increased genomic diversity on the improvement to clinical care and in turn, precision medicine. Genetic variants vary in frequency from person-to-person, and therefore these variants vary from population group to population group. Variants which affect drug response or a particular disease will also then vary in the same manor.

Therefore, including more African individuals in genomic research has the potential to uncover more novel pathogenic or drug affecting variants which may not be present in European populations. These novel variants could have clinical implications which could affect how treatments or drugs are administered for African population and could have the potential to save or improve lives of the people living across our continent.

As a continent with such a large disease burden coupled with the fact that African populations are so genetically diverse (Dandara et al. 2019), there could be millions of clinically-associated variants waiting to be discovered and implemented in current practice.

Currently, there is progress. Initiatives such as H3Africa, TopMed, CAAPA, PAGE II, and the Million Veteran Program have contributed greatly to closing the genomic gap and their results are encouraging. We do see with an increase in diverse genomic studies, we see an increase in diverse and novel genomic variant discovery as well as positive clinical and pharmacogenomic applications for individuals of African ancestry.

It will require some work, but the future is bright, and it does feel like the perfect day to go swimming.

References:

1. Baker, J.L., Shriner, D., Bentley, A.R. and Rotimi, C.N. 2017. Pharmacogenomic implications of the evolutionary history of infectious diseases in Africa. Pharmacogenomics Journal 17(2), pp. 112–120. doi: 10.1038/tpj.2016.78.
2. Dandara, C., Masimirembwa, C., Haffani, Y.Z., Ogutu, B., Mabuka, J., Aklillu, E. and Bolaji, O. 2019. African Pharmacogenomics Consortium: Consolidating pharmacogenomics knowledge, capacity development and translation in Africa. AAS Open Research 2. doi: 10.12688/aasopenres.12965.1.
3. König, I.R., Fuchs, O., Hansen, G., von Mutius, E. and Kopp, M. V. 2017. What is precision medicine? European Respiratory Journal 50(4). doi: 10.1183/13993003.00391-2017.
4. Omotoso, O.E., Teibo, J.O., Atiba, F.A., Oladimeji, T., Adebesin, A.O. and Babalghith, A.O. 2022. Bridging the genomic data gap in Africa: implications for global disease burdens. Globalization and Health 18(1). doi: 10.1186/s12992-022-00898-2.
5. Zhang, C., Hansen, M.E.B. and Tishkoff, S.A. 2022. Advances in integrative African genomics. Trends in Genetics 38(2), pp. 152–168. doi: 10.1016/j.tig.2021.09.013.