Biology subjects

Morin, G.-P.

Publications and source records attributed to Morin, G.-P..

2 recordsLinked to original sources

bioRxiv2026

Continuous ancestry profiles from genomes and genealogies

Using a single population label to represent an individual's ancestry may offer convenience, but ancestry is multidimensional, continuous, and reflects contributions from multiple ancestral sources. Here, we demonstrate empirically that ancestry profiles outperform categorical ancestry labels in capturing this complexity. Relatedness among 28,332 genotyped individuals was measured using haplotype painting and ordination and was regressed on regional ancestry proportions from the deep genealogies available for one-third of the cohort. When tested on participants in a validation set, predicted profiles placed 78% of documented ancestry in the correct region, against 48% for the training set average. Giving each participant a single regional label placed only 32% of their documented ancestry correctly, and a perfect classifier naming each person's largest documented region would reach only 38%, because most individuals carry ancestry from several regions. Thus, the continuous profile captures substantially more ancestry than any classification, providing support for representing ancestry as a continuum rather than a label.

genetics↗

bioRxiv2025

Fine-scale structure of a whole regional population through genetics and genealogies

The Saguenay-Lac-Saint-Jean (SLSJ) region of Quebec, Canada, a population shaped by a prominent founder effect, has long been considered genetically homogeneous. This study comprehensively investigates the fine-scale population structure within SLSJ by integrating genotype data from the CARTaGENE cohort with extensive genealogical records from the BALSAC population register. A time-efficient algorithm was developed to compute billions of kinship coefficients from genealogies in order to analyse an entire generation. We demonstrate a striking concordance between realised (genetic) and expected (genealogical) kinship (r = 0.78). From both kinship measures, we reveal fine-scale population structure at the municipal level within SLSJ, challenging the notion of regional homogeneity. Our analysis highlights an east-west genetic gradient and uncovers migratory streams and differential founders genetic contributions that shaped the genetic landscape of this population. This research provides insights into the interplay of genetics, demography, and historical events, underscoring the importance of fine-scale population structure in genetic studies and reaffirming the power of large-scale genealogical data.

genetics↗