The evolutionary history of humans

Modern genomic analysis is able to provide insights into our evolutionary past, as researchers can analyse the genetic material passed from one generation to the next. Our genomes also impact on our health – predisposing us to disease, or modifying how our bodies respond to treatment. Despite the importance of genomic analyses, the vast majority of genetic studies to date have used data from people of European ancestry1. The disparity means our understanding of diversity in the human genome is limited, and many populations remain understudied. A lack of understanding can also worsen health inequalities – as findings from Europeans have limited usefulness in different populations.

Mohamed Almarri works in the Sanger Institute Human Genetics Programme, and has recently been awarded his PhD. During his studies, he has extended the knowledge of global genetic diversity and uncovered important insights into population history. He has studied structural variations in the genome in a diverse set of populations, as part of the Human Genome Diversity Project. He has also collected and analysed genomes from Middle Eastern populations, helping to uncover the region’s history. We spoke about his work and the importance of diversity in genomics.


Why did you become a scientist?

I was inspired by a teacher I had in high school who taught me genetics. I remember being curious about the differences between people – like why one person is taller than another, for example. I also really like history, and so using evolutionary genetics to study human history, and in turn showing how human history has shaped our genetics and our diseases, fascinates me. When I was growing up in Dubai, there weren’t really any role models for me to look up to in science. I think without that teacher, I wouldn’t have taken the path I did.

Tell us about your work

In the early 1990s, a group of scientists started a project to sample diverse human populations from all over the world. The data set is a resource for genetic studies into human history, evolution, and disease. At Sanger, we undertook whole-genome sequencing of the samples. Together with my group led by Dr Chris Tyler-Smith2, I analysed the data – it was the most varied set of human genomes ever published, representing a good cross-section of human diversity. We found substantial amounts of common, previously undocumented, genetic variation3. Our findings shed light on ancient human history, showing how populations migrated and mixed hundreds of thousands of years ago.

In my more recent work, I have collected and studied genomes from populations in the Middle East. It is an important region to understand human evolution and migrations, but is underrepresented in genetic studies. We were able to show how populations in the region mixed and migrated over the millennia, and how this correlates with the changing environment and the birth of agriculture. Our results give detailed insights into the genomic histories of the Middle East.4

Why is diversity so important?

Science is global and collaborative, but I think having representatives from the regions you’re analysing is important. I’m from the United Arab Emirates, and one of my colleagues who worked on this at Sanger is from Lebanon. We’re aware of sensitives that might come in to play. We collaborate with archaeologists from the regions we study too – I think that’s vital.

It’s also important for studying disease. Some conditions are more prevalent in certain populations. In the Middle East, Type 2 diabetes is very common, and there may be genetic variants that are associated with the disease that aren’t present in other populations. If we don’t know what the frequency of those variants is in Middle Eastern populations, then that is a real barrier to understanding disease and disease risk.    

How do you hope your findings will be used?

Since we published the study on Middle Eastern populations as a pre-print, I’ve had many scientists from the region get in touch. I hope to start new collaborations – I’m quite excited by that. I hope there will be more studies into the genetics of people in the region. And I really would like to inspire a new generation of scientists – those who are in school now.


References and more information

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7380073/
  2. https://www.sanger.ac.uk/person/tyler-smith-chris/
  3. https://science.sciencemag.org/content/367/6484/eaay5012.full
  4. https://www.sanger.ac.uk/news_item/genetic-study-reveals-ancient-human-adaptation-to-agriculture-and-climate-change-in-middle-east/