Publications

Background: The South Caucasus region, including Armenia, is recognized as a center of early viticulture, home to the oldest known winery and a rich tradition of winemaking. Armenia's topography … has contributed to the preservation of genetically diverse grapevine populations. Cultivated grapevines (Vitis vinifera ssp. vinifera or V.V. ssp. vinifera) and their wild ancestor (V. vinifera ssp. sylvestris or V.V. ssp. sylvestris) exhibit high genetic diversity, making them valuable resources for understanding domestication, adaptation, and breeding. Despite Armenia’s historical and economic importance, the genomic diversity of its wild and cultivated grapevines remains underexplored. We re-analyzed whole-genome sequencing data of 164 grapevine accessions from Armenia, including cultivated and wild individuals, taken from a previous study on worldwide collected vine accessions to characterize genomic diversity, population structure, and domestication history of this gene pool. Results: Our analysis uncovered genetic patterns partly unique to Armenia. Population structure analysis revealed a clear genetic separation between wild and cultivated groups and three distinct ancestral components within the cultivated gene pool, reflecting a west-to-east geographical gradient in Armenia. This genetic cline correlates with a shift in usage, from table to wine grapes, and a transition in berry skin color from white to black. Additionally, we identified four distinct subgroups within wild populations in Syunik, suggesting notable diversity. Evolutionary history analysis indicates that wild and cultivated lineages began to separate ~18.5k years ago, with divergence intensifying ~4k years ago under human cultivation. Comparative genomic scans for divergent selection identified genomic regions associated with domestication traits, including disease resistance and biosynthesis of anthocyanin and flavanol. Genome-wide association, including k-mer-based approach studies, uncovered candidate markers linked to agronomic traits, such as berry skin color and bunch density. These results provide genomic resources and highlight targets for grapevine improvement and conservation. Conclusions: This whole-genome study on the genetic diversity of wild and cultivated grapevines from Armenia provides a valuable resource for identifying candidate genes and domestication-related regions associated with agronomic traits. The results underscore the importance of conserving local grapevine diversity in Armenia, a historically significant and genetically rich viticultural region.

Inferring the genetic structure of populations at the subpopulation level is crucial for understanding the evolutionary forces and demographic histories that shape genetic diversity. Among the most … widely used approaches in population genetics are methods based on admixture and structure modeling—named after the respective software tools—which have become standard due to their intuitive, interpretable outputs. In this study, we address a key methodological question: how does traditional admixture-based decomposition of genetic components in multilocus population data relate to clustering approaches that leverage machine learning, specifically Self-Organizing Maps (SOMs)? We implemented this approach through our custom SOM-based tool, SOMmelier, which enables the portrayal of genetic structure by identifying modules of co-mutated SNPs and arranging them in a topology-aware genetic landscape. In this context, topology-awareness refers to the organization of genetic modules in a two-dimensional map, where their spatial proximity reflects mutual similarity. As a case study, we applied SOMmelier to investigate the population genetics of European grapevine. Based on prior literature, we considered up to six genetic components, which formed a genetic landscape that closely mirrors the geographic expanse of the classical Mediterranean world—from Western Asia through the Caucasus to Western Europe. The resulting topology reflects the dynamic spatial and temporal nature of grapevine domestication and diffusion. SOMmelier thus represents a complementary and powerful framework for genetic data analysis. By integrating the topological structure of SNP co-variation, it offers new perspectives on population structure, evolutionary history, and trait associations in grapevine—and has broader applicability to other species and systems in population genetics.