Top: Map showing the emergence of the "I" Haplogroup in eastern Europe from the Middle East about 28,000 years ago. The subsequent mutations into the sub-group I-M253, where the Otterson paternal line shows up, probably emerged in Europe 15,000 years ago, and later in Denmark, Sweden and Norway around 1,700 BC.
Above: Areas of Viking settlement in the Nordic Bronze Age.
Right: Petroglyph, or rock carving, of a Viking long boat, Tanum, Sweden. Thousands of Bronze Age rock carvings have been discovered in Sweden depicting everyday life. Rock carvings of ships are especially common.
Below: Reconstruction of a Viking longhouse in Landa, Norway.
The Nordic Bronze Age
The Nordic Bronze Age emerged about 1750 BC from previous Scandinavian cultures, in the southern part of the Scandinavian peninsular of what is now Denmark and parts of Norway and Sweden.
Settlement in the Nordic Bronze Age consisted mainly of single farmsteads on the high ground along coastal areas. Each settlement was dominated by the longhouse, which was home to either an extended family or multiple families. Basic agriculture, including the growing of wheat, millet and barley, along with the raising of domesticated animals - cows, sheep and pigs - was supplemented by fishing and hunting of deer and elk.
But it was in metalworking that the Vikings of this period excelled, made possible by significant trade with Central Europe. That trade depended on the Viking export of amber, a fossilized tree resin notable for its natural beauty, in exchange for precious metals. The trade route between the Viking settlements and Central Europe is known to historians as the Amber Road, and was fiercely defended when necessary by otherwise generally peaceable Vikings. Only many centuries later did the Vikings became known for their brutal and unrelenting coastal raids on neighboring foreign shores.
The Bronze Age settlements became highly skilled in working the imported precious metals into decorative ornaments, helmets and weapons. The Nordic Bronze Age became one of the richest metalworking cultures in Europe.
Thousands of artifacts from this period have been found in the burial mounds across the region. According to scholars, At least 50,000 burial mounds were built in Denmark alone between 1500 and 1150 BC.
Genealogical research using written documents can only take us back so far - perhaps two or three hundred years. If we are lucky, and if our ancestral lines include the wealthier classes or even nobility, we may trace our families back several more centuries. But at some point, we simply run out of written records and may even find ourselves in an era before surnames began. And that’s where the rapidly developing science of DNA genealogy comes in.
Who were the earliest ancestors of the Ottersons of north-east England? The latest Y-DNA evidence for the Otterson paternal line links them to the Nordic Bronze Age, 3,700 years ago, in an advanced Viking culture occupying Denmark and the southern part of Sweden and Norway. How reliable is that evidence, and what did that ancient world look like?
What is a Haplogroup?
Research into ancient civilizations using modern DNA testing is a science, and like all sciences the methods and the language can be intimidating to non-scientists. At the risk of over-simplification, here are some definitions in laymen's terms of some of the most common vocabulary encountered in DNA genealogical research:
Haplogroups, Y-DNA, mitochondrial and autosomal DNA
A haplogroup describes a particular branch, or related branches, of the genetic human family tree. When scientists analyze a person's DNA, they can identify the genetic matches with known ancient groups all over the world. Because they know which haplogroups occupied which parts of the world and in which time periods, we can get an approximate idea of where some of our ancestors lived.
However, both Y-DNA (father's male line) and mitochondrial DNA (mother's female line) represent only a small fraction of a person's total ancestry. This type of analysis will tell you where, and roughly when, ancestors on these two specific lines probably lived thousands of years ago, but it will tell you nothing about your more recent history or necessarily where thousands of your other ancestral lines came from.
To learn about more recent ancestry back to 500 or even 1,000 years - analysts look at autosomal DNA, which undergoes recombination every successive generation. Autosomal DNA represents a sizable chunk of our total DNA, and therefore presents a much broader picture of all of our ancestors. This type of DNA analysis may also allow us to connect more easily with other living relatives who share the same DNA and have also taken DNA tests for genealogical purposes.
This is why people sometimes question why different DNA samples show different results - the different analyses of Y-DNA, mitochondrial DNA and autosomal DNA are reflecting different people and different time periods. Like looking at a 1,000-piece jigsaw puzzle, one type of analysis shows most of the picture, while other methods appear to focus on a single jigsaw piece. All are correct and all are useful for what they are measuring, as long as we understand the difference.
Autosomal DNA: The Bigger Picture
DNA matches with others who have tested their DNA confirms what we have learned so far about where the Ottersons and related lines were found in the past two or three centuries. The majority were found in and around the city of Sunderland in what was formerly County Durham, and surrounding towns and villages.
Ancestry.com produced these maps based on an autosomal DNA test for Mike Otterson, this site's webmaster. Unlike the Y-DNA test which traces only the father's paternal line back to pre-history, autosomal DNA takes in a much larger proportion of a person's DNA and so captures the genetic history of both parents. The resultant map (above left) still shows the influence of Nordic ancestors, but now includes the British Isles. This is unsurprising, since this history is also much more recent, and almost all of the ancestors on this subject's family tree lived in England for the past two or three hundred years.
Ancestry.com takes this study one step further, and looks for matches among other people who have submitted their DNA. If those matches identify a common area of habitation, it describes this as a "community" and produces a community map (above right). In this particular case, Ancestry.com correctly identified the primary areas where Mike Otterson's ancestors lived - north-east England, especially County Durham. This match was only possible because other related individuals from the same area had submitted their DNA for testing. The more people who submit their DNA, the more accurate the picture becomes.