Each person's collection of DNA values is referred to as their haplotype. Scientist have sorted and classified haplotypes into haplogroups, which provides a clue as to the ancient background of the population. Maps showing geographic distribution of the various Haplogroups can be found using the "more about" links
R1b This is the most common haplogroup in Western Europe, reaching over 80% of the population in Ireland, the Scottish Highlands, western Wales, the Atlantic fringe of France, the Basque country and Catalonia. Many of the participants in the SLADE project belong to the R1b haplogroup. The haplogroup is widely dispersed across Europe and is believed to be descended from hunter-gathers who arrived in Europe before the last Ice Age 40,000 years ago. . . more about R1B . .
I The "I" group sometimes referred to as the "Viking" haplotype, found in Scandanavia and parts of Ireland, Scotland, and England, where it's thought to denote descent from the Viking invaders. The Balkan countries likely harbored this subgroup of I during the Last Glacial Maximum. Today, this branch is found distributed in the Balkans and Eastern Europe, and extends further east with Slavic-speaking populations. . . more about I1 . .
J 2 Haplogroup J2 is thought to have appeared somewhere in the Middle East where it later spread throughout the Mediterranean, central Asia and south into India. . . more about J2 . .
E 3a It is currently hypothesized that this haplogroup dispersed south from northern Africa within the last 3,000 years with the Bantu agricultural expansion. E3a is also the most common lineage among African Americans. It can be found at its highest frequency in Senegal and is also found at a very low frequency in North Africa and the Middle East. . . more about E3a . .
R 1a The R1a lineage is believed to have originated in the Eurasian Steppes north of the Black & Caspian Seas. This lineage is thought to descend from a population of the Kurgan culture, known for the domestication of the horse (circa 3000 B.C.E.). These people were also believed to be the first speakers of the Indo-European language group. This lineage is found in central & western Asia, India, and in Slavic populations of Europe. . . more about R1a . .
G2a Haplogroup G is believed to have originated around the Middle East during the late Paleolithic. Haplogroup G is currently found all the way from Western Europe and Northwest Africa to Central Asia, India and East Africa, although everywhere at low frequencies. The only exceptions are the Caucasus region, central and southern Italy and Sardinia, where frequencies typically range from 15% to 30% of male lineages. . . more about G2a . .