Viking and Danish London

“Vikings from Denmark launched raids on London during the 9th and 10th
centuries. The Danish King Cnut became King of England in 1016 and
Danish merchants came to London to trade.  Viking raiders from Denmark
attacked London in 842, 851 and many times afterwards as part of a
sustained campaign of plunder and settlement. This led the Anglo-
Saxons to retreat to the remains of the Roman walled city of London
for protection. The Vikings spent the winter in London in 871-72. By
the 880s, Vikings were settling in eastern England. The English King
Alfred made an agreement with the Viking leader Guthrum to partition
the country. However, renewed attacks from the late 10th century
resulted in the Danish leader Cnut becoming King of England in 1016.
Twenty five years of Danish rule followed, with Danish merchants
trading in London. This period of Scandinavian influence on London
life finished when Edward the Confessor was crowned king in 1042. The
age of invasions ended in 1066 with his successor, William the

Viking mice conquered much of British Isles
BY Ewen Callaway  /  01 October 2008

They may not have raped and pillaged, but “Viking” mice conquered the
outer reaches of the British Isles all the same. Rodents living in
Wales, Scotland and Ireland can trace their ancestry to Norwegian
house mice, presumably stowaways on Viking ships. Because grain-eating
house mice – Mus musculus domesticus – depend on dense human
populations, they serve as a reliable proxy for human settlement and
migration, says Jeremy Searle, an evolutionary biologist at the
University of York, UK, who led the new study. “It’s just a completely
different angle to look at and potentially add new pieces of evidence
that historians and archaeologists can use,” he says. The discovery
that mice made the journey to the northern and western British Isles
at the time of the Vikings isn’t much of a surprise in itself. The
Orkney Islands served as a major Norwegian Viking settlement in the
11th and 12th centuries, and rodents probably sailed between
Scandinavia and Scotland.

Earlier settlers
What surprised Searle’s team was the difference in mitochondrial DNA
from these “Viking” mice and those recovered in other parts of
Britain. When they examined the ancestry of rodents from elsewhere in
the British Isles, they found a link to Bronze Age human migrations,
beginning about 2300 BC. This probably means that the Vikings were the
first humans to live densely enough in Scotland and Ireland to support
house mice, Searle says. “If a place is empty of mice the first that
come are the winners,” agrees François Bonhomme, an evolutionary
biologist at Montpelier University, France, not involved in the study.
“One boat with three mice – that’s sufficient to start a population.”
Other such human and house mice populations should prove more
interesting and enlightening, Searle says. “Now that we’ve got a
Viking mouse, if you like, we can actually focus on much more specific
aspects of Viking history.”

For instance, mice could solve two puzzles about the settlement of
Iceland. Some historians think that Iceland was home to multiple
Viking settlements, each with a different home base in the Viking
kingdom, a contention that mice could bolster. Also, the Hebrides may
have served as a pit stop from Norway to Iceland, where Viking men
picked up women for second leg. This theory might be confirmed if DNA
from Icelandic mice most closely matches that of Hebridean mice.

Jeremy Searle
email : jbs3 [at] [dot] uk

Journal reference: Proceedings of the Royal Society B: Biological
Sciences, (DOI: 10.1098/rspb.2008.0958)
“The west European subspecies of house mouse (Mus musculus domesticus)
has gained much of its current widespread distribution through
commensalism with humans. This means that the phylogeography of M. m.
domesticus should reflect patterns of human movements. We studied
restriction fragment length polymorphism (RFLP) and DNA sequence
variations in mouse mitochondrial (mt) DNA throughout the British
Isles (328 mice from 105 localities, including previously published
data). There is a major mtDNA lineage revealed by both RFLP and
sequence analyses, which is restricted to the northern and western
peripheries of the British Isles, and also occurs in Norway. This
distribution of the ‘Orkney’ lineage fits well with the sphere of
influence of the Norwegian Vikings and was probably generated through
inadvertent transport by them. To form viable populations, house mice
would have required large human settlements such as the Norwegian
Vikings founded. The other parts of the British Isles (essentially
most of mainland Britain) are characterized by house mice with
different mtDNA sequences, some of which are also found in Germany,
and which probably reflect both Iron Age movements of people and mice
and earlier development of large human settlements. MtDNA studies on
house mice have the potential to reveal novel aspects of human


Bronze Age mouse offers clues to royal shipwreck  /  9.11.2008

Remains of a long dead house mouse have been found in the wreck of a
Bronze Age royal ship. That makes it the earliest rodent stowaway ever
recorded, and proof of how house mice spread around the world.
Archaeologist Thomas Cucchi of the University of Durham, UK,
identified a fragment of a mouse jaw in sediment from a ship that sank
3500 years ago off the coast of Turkey.

The cargo of ebony, ivory, silver and gold – including a gold scarab
with the name of the Egyptian queen Nefertiti – indicates it was a
royal vessel. Because the cargo carried artefacts from many cultures,
its nationality and route is hotly debated, but the mouse’s jaw may
provide answers. Cucchi’s analysis confirms it belonged to Mus
musculus domesticus, the only species known to live in close quarters
with humans (Journal of Archaeological Science, vol 35, p 2953). The
shape of the molars suggests the mouse came from the northern
Levantine coast, as they are similar to those of modern house mice in
Syria, near Cyprus. And, when generations of rodents live aboard
ships, they evolve larger body shapes. Yet this mouse was roughly the
same shape and size as other small, land-dwelling mice of the time,
suggesting it boarded just before the ship set sail.

The presence of the mouse indicates that the Royal vessel was
carrying, as well as its riches, a large shipment of grain, either to
trade or feed the crew. And the most likely place to load up on grain
was the port of Minet el Beida, which served the ancient city of
Ugarit, the largest international trade emporium between the 14th and
13th centuries BC. “A seemingly insignificant discovery within a
vessel crammed full of exquisite and exotic goods provides a useful
piece of evidence for the ship’s route 3500 years after its final and
fateful journey,” says Cucchi. What’s more, “this single tiny mandible
of a house mouse represents the earliest direct evidence for the
stowaway transport of commensal rodents,” he says, highlighting how
important Bronze Age shipping helped spread an invasive species around

Thomas Cucchi
email : thomas.cucchi [at] [dot] uk

Beastly tales: Rewriting human history
BY Bob Holmes  /  19 January 2008

According to the history books, the Madeira archipelago 600 kilometres
west of Africa was discovered in 1419 when Portuguese mariners were
blown off-course by a storm. In Roman times Pliny and Plutarch wrote
about islands that might be Madeira, but there is no definite account
of the islands, nor any signs of people, prior to the arrival of the
Portuguese. The mice of Madeira Island, however, tell a different and
unexpected story.

The mice are not native to the island and must have arrived on
European ships. Genetically, they most closely resemble the mice of
Portugal. However, some of their DNA has strong similarities to that
of mice found in Scandinavia – a strong hint that Viking ships found
Madeira long before the Portuguese. “It might have been a temporary
occupation, or just a few boats landing for a short period of time,”
says Jeremy Searle, an evolutionary biologist at the University of
York in the UK and an author of the study (Heredity, vol 99, p 432).
“But the mice are telling us something that no artefact so far has
told us.”

Madeira’s mice are not an isolated case. Like spies in the halls of
history, our animal and plant companions hold lost secrets about our
past. Through their genes we can trace the paths of ancient migrations
and trade routes, and sometimes unpick the knot of successive waves of
colonisation. Plants and animals can also help archaeologists date the
origin of some of the major innovations of human culture, such as the
first use of clothing and the beginning of high-density urban living.
They can even help researchers glimpse the motives of ancient peoples
as they laid the cornerstones of civilisation.

For instance, anthropologists have long been fascinated by one of the
greatest seagoing migrations ever undertaken – the colonisation
thousands of years ago of the remote islands of the south Pacific.
Where did these ancient colonists come from? Did they spread through
Polynesia in a single, rapid sweep, or was it a gradual move
undertaken in several waves? The most obvious way to answer questions
like these would be to study the DNA of Polynesian people. If they
carry genetic variants shared only with, say, natives of Taiwan, that
would point to a likely origin for the migration.

Ancestral DNA
However, this kind of study is not as simple as it sounds. Any clear
genetic patterns that may once have existed would have been blurred
over the past few centuries, making comparisons among modern people
uncertain. A better alternative would be to extract DNA from human
remains that pre-date European contact, but such remains are
relatively scarce and, understandably, most communities do not want
the bones of their ancestors ground up to extract DNA.

“If people don’t want their ancestors to be studied, then you just
don’t do it,” says Lisa Matisoo-Smith, a molecular anthropologist at
the University of Auckland in New Zealand. “So I said, how can we get
at this in another way?”

She knew that the early colonists did not travel alone in their
canoes. They brought pigs, chickens, dogs and even rats along with
them. Perhaps, she thought, these domestic animals held the answer:
the relatedness of the animals on different islands should be similar
to that of the humans who brought them.

The rats proved especially helpful. Unlike the European rat, the
Pacific rat, Rattus exulans, dislikes water and would not have
scuttled aboard a boat of its own volition. Instead, the colonists
took them for food. “The rats on the islands today are the direct
descendants of the rats that arrived with the pre-European human
population,” Matisoo-Smith says. This means there has been no later
genetic “blurring”, so she could simply study modern rats rather than
searching out ancient rat DNA.

Matisoo-Smith and her colleagues collected rat tissue from islands
throughout the Pacific as well as from mainland Asia, and sequenced a
short part of their mitochondrial DNA. This revealed two separate
lineages of rats: one type in the Philippines, New Guinea and other
islands of the western Pacific; and another on the more remote islands
further to the east. Such a pattern is unlikely to be the result of a
single wave of human migration, so the researchers concluded that
there must have been at least two separate waves of colonisation
(Proceedings of the National Academy of Sciences, vol 101, p 9167).

Bone of contention
Similar genetic analyses of pigs, chickens and dogs – using ancient
DNA to avoid the blurring caused by the extensive trade in these
animals – has turned up evidence of even more intricate settlement
patterns. “It’s not that people came once and then there’s isolation,”
says Matisoo-Smith. “It’s a much more dynamic process. The Pacific
really is a highway. Once you have people moving, and you have
knowledge of the island world, then everybody’s going to take
advantage of that.”

Last year, the team turned up a big surprise: a single chicken bone,
taken from a pre-Columbian archaeological site in Chile and dated to
about AD 1400, yielded DNA sequences identical to those of prehistoric
chickens from Tonga and Samoa in the south Pacific. This is the
strongest evidence yet that Pacific islanders’ journeys took them all
the way to South America on at least one occasion (PNAS, vol 104, p

It might not be time to rewrite the history books yet, though.
“There’s only one bone, and there’s one sequence, and there’s one
date, which is just old enough. I’m happy with the data, but they need
more of it,” says Keith Dobney, a zooarchaeologist at Durham
University in the UK.

The worry is that because so little DNA remains in ancient specimens –
especially in the warm, damp tropics – attempts to sequence it can be
ruined by contamination with modern DNA. “One has to be sure there’s
no other explanation for the chicken DNA in the bone. It could be
something as ridiculous as that the archaeologist who handled it had
chicken for lunch that day,” says Tom Gilbert, a specialist in ancient
DNA at the University of Copenhagen in Denmark.

Trade routes
With more samples, careful handling and the latest techniques, though,
studies of ancient DNA can yield solid results. Several research
groups have now used this technique to track human migrations. Similar
approaches can also be used to unravel ancient trade routes, for
instance by tracing the weevils found in Roman granaries in England
back to their roots in the Mediterranean, a study which Gary King at
the University of York is now beginning. If the same genotypes of
weevils also turn up in medieval English granaries, it will show that
the English were producing and storing grain throughout the Dark Ages.
If, on the other hand, medieval weevils are different, it will confirm
the idea that there was a period when grain was produced and stored
only sporadically, causing the original colonists to die out.

The use of genotypes to study ancient trade routes has already thrown
up one surprise. Anders Götherström, an evolutionary geneticist at
Uppsala University in Sweden, has found African cattle genotypes in
Bronze Age archaeological sites in Spain. This suggests that, even
thousands of years ago, trade across the Strait of Gibraltar was
extensive enough to include live cattle (PNAS, vol 102, p 8431).

Before Götherström’s study, people had noticed the presence of African
genotypes in Spanish cattle, but assumed that they had arrived with
the conquering Moors in the 8th century. “Nobody expected it to be any
earlier than that,” says Götherström. “As long as we were relying on
modern cattle DNA, we made the wrong conclusion. When we go back in
time, we can see when it really came. It was there during the Bronze

Our companion species can reveal even more subtle things about our
history. The human head louse, for example, lives only in scalp hair.
A closely related subspecies, the body louse, lives only in clothing,
and so must have evolved from the head louse sometime after early
humans created a new niche for them by wearing clothing regularly.
Assuming this did not take long, dating the divergence of the two
louse subspecies should give us a rough idea of when clothing became

Recent invention
To do this, Mark Stoneking and his colleagues at the Max Planck
Institute for Evolutionary Anthropology in Leipzig, Germany, sequenced
DNA fragments from 40 head and body lice, and counted the genetic
differences between the two. They then compared this with the number
of genetic differences between human and chimpanzee lice, which are
assumed to have diverged when proto-humans and chimps went their
separate ways about 6 million years ago. Based on this comparison, the
researchers estimate that human head and body lice must have diverged
about 72,000 years ago, suggesting that clothing is a relatively
recent human invention (Current Biology, vol 13, p 1414).

While this work shows that much can be learned simply by looking at
how closely plant or animal populations are related, some researchers
are delving deeper. The latest trend in the growing field of genetic
archaeology is to look at variations in the genes for specific

One of the best examples comes from a study of flax plants led by
Robin Allaby, a molecular archaeobotanist at the University of Warwick
in the UK. Flax is unusual among crop plants because it provides two
products – oil from the seeds, and fibre. Archaeologists disagree on
which came first, so Allaby decided to read the genes directly. He
collected a wide variety of flax lines and sequenced portions of a
gene called sad2, which plays a role in the production of unsaturated
fatty acids in the seeds. From these sequences he was able to
reconstruct the genetic history of flax, which revealed that the
ancestral form of sad2 was similar to the form typical of modern
oilseed flax. Variants typical of fibre flax only appear relatively
recently, suggesting that ancient people domesticated flax for its
oil, rather than its fibre (Theoretical and Applied Genetics, vol 112,
p 58).

As this shows, focusing on particular genes can sometimes tell us more
than conventional archaeological artefacts. Applying the same approach
to domestic animals should reveal, for example, when ancient people
first began breeding cattle for milk or meat, Götherström says. He is
now looking at DNA extracted from bones and teeth found in horse
graves in the hope of determining whether certain colours of horse had
greater ceremonial value in ancient times.

And this is just the start. As we sequence the genomes of more and
more organisms, we will get ever better at reading the genetic runes,
and researchers like Götherström should be able to uncover many more
stories hidden within DNA of our plant and animal companions.
Undoubtedly there will be many more surprises to come.

Lisa Matisoo-Smith
email : e.matisoo-smith [at] [dot] nz

Robin Allaby
email : R.G.Allaby [at] [dot] uk

Vincent S. Smith
email : vince [at] vsmith [dot] info / v.smith [at] [dot] uk

David L. Reed
email : dreed [at] flmnh.ufl [dot] edu

Lice from mummies provide clues to ancient migrations
BY John Noble Wilford  /  February 6, 2008

When two pre-Columbian individuals died 1,000 years ago, arid
conditions in the region of what is now Peru naturally mummified their
bodies, down to the head lice in their long, braided hair. This was
all scientists needed, they reported Wednesday, to extract well-
preserved louse DNA and establish that the parasites had accompanied
their human hosts in the original peopling of the Americas, probably
as early as 15,000 years ago. The DNA matched that of the most common
type of louse known to exist worldwide, now and before European
colonization of the New World.

The findings thus absolve Columbus of responsibility for at least one
unintended tragic consequence to the well-being of the people he
discovered and called Indians. The Europeans may have introduced
diseases, most notably smallpox and measles, but not the most common
of lice, as had been suspected. Of possibly greater importance,
evolutionary biologists say, the new research technique may become a
tool in studying other mummies for valuable insights into human
migrations and the spread of disease. Lice have been found on Egyptian
mummies, for example, but these have yet to undergo genetic

The analysis of lice from the Peruvian mummies is described in a paper
to be published Feb. 15 in The Journal of Infectious Diseases. The
principal authors are Didier Raoult of the National Center for
Scientific Research in Marseille, France, and David Reed of the
Florida Museum of Natural History in Gainesville. The scientists
conducted independent studies on samples from the two mummies, which
were among those collected between 1999 and 2002 in the high coastal
desert of southern Peru by Sonia Guillen, a Peruvian anthropologist.
Looters had destroyed the bodies, leaving only the heads of people who
had died around the year 1025. Lice have also been recovered from New
World mummies as old as 10,000 years.

The results of the DNA tests by the two laboratories were identical,
the researchers said. They showed that 11th-century Americans already
hosted the prevalent type-A strain of lice. Currently, the researchers
said, “the most likely theory” is that type-A head and body lice
originated in Africa and were distributed worldwide long ago. Type-B,
which infests only the head, is also common, and type-C is rare, known
primarily in Ethiopia and Nepal. Pubic lice are an entirely different

Lice from other mummies with hair still intact, the scientists said,
may “help us understand the distribution of types A and B in the
Americas and the Old World before globalization.” Diseases spread by
lice include epidemic typhus, trench fever and relapsing fever, which
are now treatable with antibiotics.  Reed, an evolutionary biologist,
said in a telephone interview that, despite the discovery of type-A
lice in pre-Columbian America, early European explorers might still be
implicated in spreading a louse-borne disease back to the Old World.
“The typhus bacterium may be native to the Americas,” he said. “There
are no records of typhus in Europe until the 1500s.”

In another example of the uses of lice in science, Mark Stoneking, a
scientist at the Max Planck Institute of Evolutionary Anthropology in
Leipzig, Germany, recently examined the assumption that body lice
evolved when humans started wearing clothes. An analysis of louse
genetics appeared to put that date at about 72,000 years ago.

Mark Stoneking
email : stoneking [at] eva.mpg [dot] de

Head lice key to clothing history
BY Kat Arney  /  29 September, 2003

An evolutionary comparison of human head and body lice has shed light
on the history of clothing. A team based in Germany has worked out
that humans probably first began wearing clothes 72,000 years ago –
give or take 40,000 years.

Their calculation is based on the fact that as species evolve, they
become distinct by inhabiting different environments and gradually
changing to suit them. While head lice live solely on the human scalp,
body lice prefer to inhabit those areas covered by clothing.

Molecular clock
Dr Mark Stoneking’s team, from the Max Planck Institute for
Evolutionary Anthropology in Leipzig, worked out when the two
organisms began to diverge and became distinct species. They compared
DNA sequences from both types of lice, arriving at their result by
counting the number of DNA mutations.

“DNA mutations occur at a roughly constant rate over time, so if you
know what that rate is, you can use the number of mutations between
head and body lice to estimate when body lice arose,” explained Dr
Stoneking. They also analysed the DNA from chimpanzee lice, and found
that the human and chimp bugs became separate species around 5.5
million years ago – not far off the time their hosts’ lineages are
thought to have diverged.

Margin of error
The calculation that clothing appeared about 72,000 years ago points
towards it being a relatively new invention, given that Homo sapiens
has probably been around for less than 200,000 years. “A large time
window is inevitable with any molecular clock approach to dating, but
even if you take the extremes of the range, the result still
associates clothing specifically with modern humans,” said Dr

Given that Homo sapiens are generally believed to have expanded out of
Africa about 100,000 years ago, perhaps clothing was invented to cope
with the cooler climes of their new habitats. Dr Stoneking’s next
project is the DNA analysis of pubic lice, using the molecular clock
to work out when humans lost the majority of their body hair.