In the latest episode of The Genetics Podcast, Patrick speaks with Dr. Jim Wilson, Professor of Human Genetics at the University of Edinburgh, about his work studying isolated populations and their unique genetic makeup. As the lead of the Viking Genes project, Jim's research explores the genetic history of Scottish islanders. They have already found several genetic variants of interest, including a BRCA1 mutation present in 1 in 20 individuals on one island, and a cardiomyopathy variant 4,700 times more common in Shetland. Discoveries like these have profound implications for population health and preventive medicine. Read on for a quick summary of the episode:
Jim shares his journey from growing up on a remote Scottish island to leading one of the most extensive studies of isolated populations. His work has revealed fascinating insights into population genetics, including evidence of Viking ancestry in Scottish islanders. However, the project took a more clinical turn when Jim began focusing on rare actionable genetic variants in these communities.
One key example is a BRCA1 variant in Orkney, where one in 20 people carry a mutation linked to breast and ovarian cancer. And as noted, there is also a cardiomyopathy-associated variant in Shetland which is 4,700 times more common there than in the general population. At the same time, 1 in 40 Shetlanders are also carriers for a mutation associated with Batten Disease, a rare and fatal genetic disorder that affects the nervous system and brain. These findings underline the role of genetic drift in isolated populations and its clinical implications.
Jim emphasizes the importance of genetic screening in these communities. Drawing parallels to established programs like J BRCA for Ashkenazi Jews in England, he advocates for implementing similar initiatives in Scotland. By screening for a panel of common actionable variants and carrier conditions like Batten disease, significant health risks could be mitigated for islanders and their global descendants.
“Most people want to know about these actionable findings,” Jim explains, highlighting remarkably high participation rates among study participants. He notes that when offered the opportunity to receive personalized genetic findings, the vast majority of individuals were eager to learn more about their genetic health risks. Jim goes on to stress the importance of screening, stating that it could lead to earlier interventions for conditions like breast cancer and hemochromatosis, as well as help prospective parents understand the risks associated with recessive alleles.
Jim also explains how isolated populations can serve as natural experiments for genetic research. In these small, closely-knit communities, certain genetic risk factors for diseases are more common, making them easier to study. This offers a big advantage for precision medicine: instead of needing to study hundreds of genetic variants, researchers can focus on just a few that account for most of the inherited risk in these populations.
For instance, in Orkney and Shetland, just two BRCA gene variants explain 93% of the BRCA-related breast cancer risk. In larger, more diverse populations like the UK Biobank, hundreds of variants are needed to explain the same level of risk. This concentrated genetic landscape makes it faster and more cost-effective to study and address inherited health risks in isolated communities.
Jim’s work blends history, anthropology, and cutting-edge genetics. His population studies extend beyond Scotland, encompassing projects with Irish travelers and other isolated groups. Whether through mapping ancestral lineages or uncovering disease-causing founder mutations, his research offers new ways to combine historical insights with modern healthcare. With the ultimate goal of using his findings to advocate for better healthcare policies for everyone, Jim is currently campaigning for funding to bring population-wide genetic screening to Scottish islands. By demonstrating the efficiency and cost-effectiveness of targeted screening in high-risk populations, he hopes to pave the way for broader and better genomic healthcare worldwide.
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