Louis Putterman and David N. Weil have discovered that the proportion of a country's ancestry which lived in Europe in 1500 explains 44% of the variation in per-capita GDP in 2000.
This is a huge influence and should have a big impact in understanding how countries - and people - achieve economic success.
The VoxEU article speaks for itself really, so have a look.
- How is the migration distributed through time - for example if most emigration to the US happened in the 1800s, the dominant effect may not be 500 years old but only 150.
- Today's ethnic classifications express only roughly the ancestry of individuals. How many ancestors do you have who were alive in 1500? The answer is: around a million (assuming 25-year generations and minimal inbreeding!). I don't think the survey purports to account for the fact that these people must have almost certainly come from more than one country.
- As the authors suggest, the really interesting area is to try to work out what it is that is passed down from these ancestors which is expressed in today's GDP figures.