LONDON — Immigration might be a hot topic in the current general election campaign, but it's certainly not a recent trend.

See also: Genetic study shows how much America really is a melting pot

New research, published in the journal Nature this week, shows how waves of invasions and migrations shaped the white population of Britain, from the Normans to the Anglo Saxons and the Belgians to the Spanish.

Researchers studied DNA samples from 2,039 white residents of England, Scotland, Wales and Northern Ireland chosen for their family roots in rural areas. The DNA they inherited from their grandparents reflects the genetic landscape of those areas in the late 1880s, researchers said.

“It has long been known that human populations differ genetically, but never before have we been able to observe such exquisite and fascinating detail," Professor Peter Donnelly, who co-led the research said about the findings in a press release.

The study found that most of eastern, central and southern England is made up of a single genetic group with a significant DNA contribution of up to 40% from Anglo-Saxon migrations.

Researchers believe that this points to an intermingling of Anglo-Saxons with locals after they started to migrate to Britain in the Fifth Century.

Image: The fine-scale genetic structure of the British population Nature

The study found that people living in Wales have the closest links to the first settlers of Britain who came after the last ice age some 10,000 years ago.

They also discovered that Vikings who occupied large parts of England after invading in 865 have left no clear genetic history, which suggests that they didn't settle in large numbers.

The only part of the UK that still has a significant Viking heritage is Orkney, where there was evidence of Norwegian DNA, which makes sense considering it was part of Norway from 875 until 1472.

The study, which also examined more than 6,000 DNA samples from continental Europeans, found that there isn't a unique group of Celtic people in the UK, with different genetic patterns for clusters in Cornwall, Wales, Northern Ireland and Scotland.

"We saw no evidence of a general 'Celtic' population in non-Saxon parts of the UK. Instead there were many distinct genetic clusters in these regions," the study says.

Additional reporting from The Associated Press