The Irish DNA Atlas: Revealing Fine-Scale Population Structure and History within Ireland
By , , , , , , , , , ,
Previous attempts to describe genetic structure in the Irish population primarily employed uniparental markers. Y-chromosome and mitochondrial haplotypes that are common within Ireland show genetic continuity with those observed in other western European populations. Within the Irish population, there appears to be significant geographic structure in Y-chromosome haplotypes. There exists a general east-west cline of declining Y-chromosome haplotype diversity, evidence of hegemony in the north-west of Ireland, and in Munster, two haplotypes associated with the north and south of that province, respectively. Furthermore, analysis of putatively Norse-origin surnames suggests little Norse Y-chromosome introgression within Ireland.
In the current study we report on the assembly of a cohort of individuals with extended ancestry from specific regions in Ireland. Using dense genome-wide SNP genotype data we have performed a number of analyses to investigate population structure and extent of admixture within Ireland. We first utilize both fineStructure to investigate the extent of fine-scale population ‘clusters’, and Estimated Effective Migration Surfaces analysis to visualize regions of low or high genetic migration within Ireland and Britain. Second, we apply regression-based admixture modelling analysis and admixture event detecting software (Globetrotter) to elucidate the extent of admixture in Ireland.