A new study by RCSI University of Medicine and Health Sciences, based in Dublin, Ireland, and Sequence Bio, a genomics and precision medicine company based in St. John’s, Newfoundland and Labrador (NL), Canada, has produced the most detailed genetic analysis from people living in the Canadian province to date. , demonstrating a unique institutional population structure that can be used to identify and study health-related genetic variants.
The study, titled “Newfoundland and Labrador: founder mosaic of an Irish and British diaspora 300 years ago,” was published in the journal Nature. Communication biology.
By studying the genetic profiles of 1,807 individual volunteers from the Sequence Bio Genome Project in Newfoundland and Labrador (NLGP), and comparing the exact genetic makeup generated from the NL to reference data sets for Ireland and England, scientists have shown that a large proportion of European-derived populations can be traced back from NL to settlers who migrated mainly from south-east Ireland and south-west England about three centuries ago.
“Looking at the ways in which Newfoundlanders and Labradorians are genetically related to each other, and even to present-day Irish and English individuals, we were able to show that European ancestry in the NL is mainly descended from Irish and English settlers in the late 18th century,” explains Dr. Edmund Gilbert, Lecturer in the School of Pharmacy and Sciences. Biomolecules at RCSI and FutureNeuro, Science Foundation Ireland (SFI) Research Center for Chronic and Rare Neurological Diseases.
Dr Gilbert, first author of the study, used well-characterized population reference datasets such as the Irish DNA Atlas to correlate English and Irish ancestry in the NL with specific regions of Ireland, and to track how social and geographical isolation affects NL communities at the level of their DNA.
Dr. Gerald Mugford, Director of Research at Sequence Bio commented on the study: “Through this expert collaboration with RCSI, we now have a much deeper understanding of the origin of the current population in the NL and the origins of genetic variants that could be meaningful for disease gene discovery in the county.”
Further analysis of the genetic data also shows multiple population bottlenecks, or declines in population size, occurring independently in the region for about 300 years due to geographic isolation and the tendency of people to settle with others of the same country of origin and religious affiliation.
Professor Gianpiero Cavalieri, Professor of Human Genetics in the RCSI School of Pharmacy and Biomolecular Sciences and Deputy Director of the SFI FutureNeuro Research Center, helped lead the comparative study of genomes from Canada, Ireland and England. He said: “Genetic analysis supports historical accounts that around 25,000 European settlers came to the NL in the 18th and 19th centuries, mainly from Ireland – predominantly Waterford, Wexford, south Kilkenny, south-east Tipperary and south-east Cork – and from Dorset and Devon in England as well as fishing ports such as Dartmouth, Plymouth or Southampton.
“In the study, we can see that Newfoundland and Labrador Catholic background is still today as strongly associated with Irish genetic ancestry as Protestant background is with English genetic ancestry.”
Dr. Michael Phillips, senior author of the study commented: “Our findings support the population structure of NL as a unique genetic landscape with founder effects.” He also noted the potential clinical and health significance of these patterns. “Because the NL is similar to other isolated island groups, there may be an opportunity to study the genetic makeup of specific subpopulations in the NL to identify rare genetic variants that contribute to the risk and severity of specific diseases.”
The study was produced in collaboration with researchers from the Genealogical Society of Ireland, Trinity College Dublin, the National Human Genome Research Institute in the US, and the Wetherall Institute for Molecular Medicine in Oxford.