5/7 Differences in EA PGS between people born in major cities and other regions are already visible from the mid-20th century and increase over time despite social changes (panel A). Movers to Tallinn or Tartu have higher EA PGS than non-migrants even in the earliest observed cohorts (panel B).

4/7 Within-family effects are smaller than between-family effects, but are significant for PGS associated with certain socioeconomic traits (panel A). They disappear when conditioning on EA PGS (panel B).

3/7 The dominant migration pattern driving this structure is movement to Estonia’s two largest cities: Tallinn and Tartu. POB and POR denote place of birth and place of residence.

2/7 Migration creates regional PGS differences even among siblings born in the same region.

1/7 Internal migration intensifies regional differences in multiple polygenic scores (PGS), most strongly for educational attainment (EA, panel B). Adjusting for EA PGS largely removes regional differences in other PGSs (panel C).

Remember the famous UKB migration paper? We found that internal migration also shapes population structure in Estonia. Key patterns replicate within families.

www.cell.com/iscience/ful...