Insular Celtic population structure and genomic footprints of migration

• DOI: 10.1371/journal.pgen.1007152
• Publication Date: 2018-01-25T18:28:32Z
• Authors: Ross P. Byrne; Rui Martiniano; Lara M. Cassidy; Matthew Carrigan; Garrett Hellenthal; Orla Hardiman; Daniel G. Bradley; Russell L. McLaug...
• Keywords: Founder effect; Ancient DNA; Human migration; Cline (biology)

Previous studies of the genetic landscape Ireland have suggested homogeneity, with population substructure undetectable using single-marker methods. Here we harnessed haplotype-based method fineSTRUCTURE in an Irish genome-wide SNP dataset, identifying 23 discrete clusters which segregate geographical provenance. Cluster diversity is pronounced west but reduced east where older structure has been eroded by historical migrations. Accordingly, when populations from neighbouring island Britain are included, a west-east cline Celtic-British ancestry revealed along particularly striking correlation between haplotypes and geography across both islands. A strong relationship subsets Northern Scottish populations, discordant geographic affinities reflect major migrations recent centuries. Additionally, proximity all samples likely reflects strata communication narrowest inter-island crossing. Using GLOBETROTTER detected admixture signals Europe estimated dates for events consistent Norse-Vikings, Anglo-Normans British Plantations. The influence former greater than previously Y chromosome haplotypes. In all, paint new picture Ireland, revealing should be considered design examining rare variation its association traits.