Between 6,800-4,000 BC, farming methods spread across Europe, but the question of how these methods spread has not been fully established.
The two competing theories are that farming spread through cultural exchange, possibly during trading or that people migrated to Europe bringing their expertise with them.
A previous study, in 2005, analysed modern pig DNA and showed that all modern pigs are descended from European wild boar. This led researchers to conclude that early Europeans domesticated pigs independently of other farming methods.
This new study, however, has discovered that the first domesticated pigs in Europe did have Near Eastern ancestry, indicating that farmers migrated to Europe, bringing their "package" of livestock and farming methods with them.
Domestic pigs of European wild boar ancestry appear soon afterwards.
September 04, 2007
Middle Eastern origin of Neolithic pigs
Via the BBC Pig DNA reveals farming history: