European population substructure: Clustering of northern and southern populations

Using a genome-wide single nucleotide polymorphism (SNP) panel, we observed population structure in a diverse group of Europeans and European Americans. Under a variety of conditions and tests, there is a consistent and reproducible distinction between "northern'' and "southern'' European population groups: most individual participants with southern European ancestry (Italian, Spanish, Portuguese, and Greek) have > 85% membership in the "southern'' population; and most northern, western, eastern, and central Europeans have > 90% in the "northern'' population group. Ashkenazi Jewish as well as Sephardic Jewish origin also showed > 85% membership in the "southern'' population, consistent with a later Mediterranean origin of these ethnic groups. Based on this work, we have developed a core set of informative SNP markers that can control for this partition in European population structure in a variety of clinical and genetic studies.