Discover your genetic ancestors

 

WHOSE BLOOD courses through your veins? Could you be a descendant of a Viking warrior or a Berber pirate? Or perhaps you are related to the Uí Neill chieftains or the kings of Laighin (Leinster)?

If so your genes will carry the proof, and a new company set up by scientists offers a service that can reveal your genetic heritage.

Today sees the launch of “Ireland’s DNA”, a direct to customer genetic ancestry service. “We are planning it as a national project. The more people that get involved, the more we can understand about Irish history from the resulting dataset,” says Dr Gianpiero Cavalleri, one of three founders of the company.

Cavalleri is a biomedical research lecturer at the Royal College of Surgeons in Ireland and heads its epilepsy genetics group. The Irish project grew out of a similar undertaking that started about six months ago in Scotland.

And that in turn came out of a book examining the genetic ancestry of Scotland, The Scots: A Genetic Journey. The authors were Dr James Wilson, a geneticist at the University of Edinburgh who works on the genetic roots of disease, and historian Alistair Moffat.

“There was huge public interest in the book,” Dr Cavalleri says, so much so that the three decided to set up a company, Scotland’s DNA, to help finance further study of the country’s collective genome.

“Now we are going to use the same concept for Ireland,” he says. He got the idea some years ago while at Stanford University. He became fascinated with the idea that you could identify past human migration by looking at the male-only part of the genome, the Y chromosome.

As males of a given lineage began their migration out of Africa, some would have been more successful than others. Untold numbers would have been killed off, but many continued to branch out into Europe and Asia. Successful migrants would have left their mark behind in the Y chromosome.

He realised that people were interested to know their links to past generations. “With DNA you can really go deep into the past to learn where your ancestors came from,” he says.

A decade ago it was tremendously expensive to deliver a complete genome but today prices have fallen and it is feasible to think of using DNA technology to identify ancestry. About 20,000 genomes have been completed so far by labs around the world and this has opened up the possibility of direct Y chromosome comparisons between individuals and groups.

The more genomes completed, the more the resolution improves, and the better the ability to see back in time. “Up until recently we might have had a genetic signature for the northwest of Ireland collectively as being Irish. What has happened since is we can split up the Irish type. The higher resolution comes from the sequencing of the human genome.”

It all comes down to comparisons. “We look for markers and see what they are telling us,” he says. “A marker is part of the DNA that is different between people. Those differences arise with each generation.”

Most of our genome is a mix of our mother’s and father’s DNA, but the Y chromosome does not mix in a substantial way. Cavalleri likens it to the Olympic torch as individual runners carry it from city to city on the way to the games.

The same torch is passed from person to person but imagine that each person is able to leave behind a mark on the torch, a small spelling change in the DNA. “By looking at those spelling changes you get a sense of how those people have moved. After all, we are part of one big pedigree.” It is all about knowing what markers are hidden in a genome pointing towards one ancestry or another.

Almost 1,000 people have so far paid to have their DNA ancestry assessed in Scotland and the work is throwing up some surprises, Cavalleri says. For example, an estimated 1 per cent of all Scotsmen are direct descendants of the Berber and Tuareg tribesmen of the Sahara, a staggering number given the lineage is around 5,600 years old.

Scots comedian Fred MacAulay assumed he had Viking origins – via Mac-Olaf or son of Olaf. This, though, proved to be wrong, Cavalleri says. MacAulay’s DNA shows that his ancestors were not Hebridean Vikings but Irish, probably a man sold in Dublin’s ninth-century slave markets and carried off. “What we think happened is the Vikings took individuals from Ireland back to Viking bases and they had children,” he says.

“There is a fascination with this type of work,” he says, and people can now participate via the company. The male Y chromosome can be traced but it is also possible to track female lines via mitochondrial DNA only passed along by female lineages.

It costs €250 to analyse both the Y chromosome and mitochondrial DNA and €210 for either one or the other. Women don’t have a Y chromosome but often co-opt either a brother’s or a father’s DNA to show the ancestry, Cavalleri says.

The data is heavily secured and can only be used for one purpose. “The data is all stored separately on a server, it is not shared with anyone,” he says. “It is only used for ancestry. It is not used for any medical purposes. It is only used to study the history of Ireland and Scotland.”

Each person gets a web page and an account and are told the distribution of their particular maternal and paternal DNA type. The analysis will show this distribution across the world, as far back as Africa, but right up to where the type is found today, he says.

For more information see irelandsdna.com

Researching royalty: DNA fit for kings

MANY FAMILIES like to lay claim to being descended from Irish kings and today DNA can help prove this relatedness. While many family names are associated with one king or another, genetic markers can deliver the proof.

Ireland before the arrival of the Normans was dynastic, with powerful local warlords controlling territories. Their high positions in society also provided the opportunity to deliver many offspring, explains Dr Gianpiero Cavalleri, a geneticist at the Royal College of Surgeons in Ireland. It means that many of the genes passed forward into later generations had their origins in a powerful dynastic leader.

The important families are well known here, for example, the Uí Néills in Ulster begun by fifth-century warlord Niall of the Nine Hostages. Family names associated with him include O’Neill, O’Conner, O’Donnell, McLoughlin, O’Rourke and others. These surnames are associated with one particular type of Y chromosome, the male-only part of the genome.

The Eoganachta were another important dynasty in fifth-century Munster led by Conall Corc, descended from founder Eoghan-Mor. This family, with surnames such as O’Donoghue, Hayes, O’Keeffe and O’Sullivan, have a different Y chromosome type.

The Eoganachta were displaced in the 10th century by the Dalcassians, originally descended many centuries earlier from Cormac Cas, Cavalleri says. Family names here include O’Brien, Kennedy, McGrath and O’Casey, to name a few.

Then there were the kings of Laighin (Leinster) led by Dermot McMurrough who invited the Normans into Ireland. Names here include Kearney, Kinsella and McMurrough.

Few leaders had the genetic impact of the great 13th-century Mongol warrior Genghis Khan. Clearly he procreated where ever he went and today his Y chromsome is seen in 0.5 per cent of the world population, or about 16 million men. – Dick Ahlstrom