Experts are asking people from north-east Wales to provide a DNA sample to discover why those from the area carry rare genetic make-up.
So far, 500 people have taken part in the study which shows 30% of men carry an unusual type of Y chromosome, compared to 1% of men elsewhere the UK.
Common in Mediterranean men, it was initially thought to suggest Bronze Age migrants 4,000 years ago.
Sheffield University scientists explain the study at Wrexham Science Festival.
A team of scientists, led by Dr Andy Grierson and Dr Robert Johnston, from the University of Sheffield is trying to find out how and why this has come about.
Dr Grierson is leading the talk at Glyndŵr University on Tuesday and wants to speak to people with ancestry in the region to discover what is known about their family history - and to provide them with an opportunity to contribute a DNA sample to the project.
"The number of people in north-east Wales with this genetic make-up is quite extraordinary," he said.
"This type of genetic make-up is usually found in the eastern Mediterranean which made us think that there might have been strong connections between north-east Wales and this part of Europe somewhere in the past.
"But this appears not to be the case, so we're still looking to find out why it's happened and what it reveals about the history of the region."
Early into the study in 2009, the academics were hoping to link the migration of men in the Bronze Age to the discovery of copper.
The metal was found at both Parys Mountain on Anglesey, and on the Great Orme at Llandudno, Conwy.
Participants who come from the same area as their paternal grandfather are asked to give a cheek swab sample for genetic analysis. It is anonymous.
Dr Grierson leads research investigating the molecular basis of neurological disorders, including motor neuron disease and Alzheimer's disease.
He said he became interested in north Wales because of the unique genetic make-up, and because it offered an opportunity to investigate the history of the area using genetics.
"It provides a novel opportunity to look at past populations," he said.
"History and archaeology depend on surviving manuscripts and objects/landscapes. So it can be very limited.
"Genetics allows us to look at the historic population through their living descendants."
The Genetic Legacy of Medieval Society in north-east Wales takes place at Glyndŵr University's Wrexham campus from 1800 BST on Tuesday 19 July.
BBC News. 2011. "'Extraordinary' genetic make-up of north-east Wales men". BBC News. Posted: July 19, 2011. Available online: http://www.bbc.co.uk/news/uk-wales-north-east-wales-14173910