Diarmuid Gavin picks up the trail of the first Irish at La Mer de Glace, one of Europe's largest glaciers, near Chamonix, France. Today the slopes are packed with skiers and people enjoying all kinds of adventure sports. But 20,000 years ago it was a different story, back then, ice was the enemy. In Programme Two, Diarmuid examines the way in which the ice-age affected the destiny of our species and also the eventual settlement of Ireland. Twenty thousand years ago as the ice tightened its grip, most of the continent of Europe - but not Ireland - had been penetrated by small groups of nomadic people.
They had ventured north on an epic journey out of Africa that had taken millennia. But the ice forced people south and places like Northern Spain became a vital refuge for our species. Then, around 12,000 years ago people ventured north again and, as we now know, the ancestors of the Irish were among them. But how did they get to Ireland? Was it overland or by sea?
At Carlingford Lough, Diarmuid takes to the sea in a 20ft currach made of leather skins and hazel wood to test the theory that the first Irish arrived here by boat. Using only materials and techniques that were available in the stone-age, boat builder Cliadhbh O Gibne shows how people could easily have crossed the seas in stages to Ireland. Prof. Peter Woodman has spent a lifetime searching for the first evidence of humans in Ireland. Based on recent discoveries from all over Ireland, Peter says that our stone-age ancestors were far more successful and more numerous than previously believed. He is now convinced that the genetic make-up of the Irish population was well established in the stone-age and that these people were just like us. They are our ancestors.
In a dimly lit cave deep under the limestone crust of the Burren in Co Clare, archaeologist Dr Marian Dowd carefullly removes the bones of a 3 year old child whose remains have been undisturbed since the bronze age. Small pieces of the 3,500 year old bone are gingerly placed in airtight containers and sent to Germany for analysis at one of the world's leading laboratories in the detection and analysis of ancient DNA. If successful this will be the oldest human DNA ever obtained in Ireland. What will it reveal about our ancestry?
In Germany, the extraction of ancient Dna from the 3,500 year old child's bone proves a great success and for the first time scientists have specific genetic information about an Irish person who lived in pre-historic times. As a postscript to Blood of the Irish, Diarmuid Gavin goes back to the Burren and collects more Dna samples to see if it is possible to find people alive today who are related to the child from the bronze age.