An investigation into fine-scale European population structure was carried out using high-density genetic variation on nearly 6000 individuals originating from across Europe.

A major East–West gradient from Russian Moscow samples to Spanish samples was identified as the first principal component.

The second PC identified a North–South gradient from Norway and Sweden to Romania and Spain.

We present a method to predict the ethnic origin of samples by comparing the sample genotypes with those from a reference set … using just summary information …and individual genotype data are not required.

via European Journal of Human Genetics – Investigation of the fine structure of European populations with applications to disease association studies.