Everyone in Iceland is related. Every member of the 300,000 population derives from the same family tree, according to genealogy website islendingabok.is.
The islendingabok.is web site hosts the online registry Íslendingabók (“The Book of Icelanders”). In it one can find information about the families of about 720,000 individuals who were born in Iceland at some point in time. Anyone who is registered in the database has free access to it.
Íslendingabók is the product of a cooperation between Icelandic company, deCODE Genetics, and Fridrik Skúlason, who first began registering genealogy information in 1988 into a program called Espólín. In 1997 Skúlason and deCODE began cooperating on registrations for genealogy research, and Íslendigabók was born.
Íslendingabók claims to be the only genealogy database in the world that covers a whole nation. More than 95 percent of all Icelanders born since 1703, when the first national census was taken, are registered in the database, along with half of all Icelanders who have lived on the island from the settlement in 874 until 1703.
The registrations in Íslendingabók are based on a whole range of sources, such as censuses, church books, the national registry, ancient scripts, annals, obituaries, and more. These kinds of documents were more accurate and better preserved than comparable documents in other countries, according to islendingabok.is, probably because Icelanders have always been interested in genealogy.
In fact, genealogy can be considered a national sport in Iceland. When people introduce their partners to the elderly members of their family for the first time, they usually ask: “Hverra manna er hann (eða hún)?” which translates to: “Who are his (or her) people?” In the Icelandic sagas, each character is introduced by a long listing of his or her ancestors.
Genealogists in Iceland say all Icelanders are descendants of the bishop Jón Arason. Arason and his partner, Helga Sigurdardóttir, had at least nine children, and all of them also apparently had large families. It is believed that every person now alive in Iceland can find this one couple someplace in their family tree. In fact, most Icelanders can find the couple at multiple places in the family tree.
You can read more about this in the Iceland Review Online at http://www.icelandreview.com/icelandreview/daily_life/?cat_id=16539&ew_0_a_id=262375.