Genetic history of the British Isles facts for kids

The genetic history of the British Isles is a fascinating study that looks at the DNA of people living in Britain and Ireland. It helps us understand where people came from and how they moved around over thousands of years. Scientists use DNA tests to find similarities and differences in the genes of people today and even from ancient times. This research helps us piece together the story of human life in the British Isles, working alongside clues from languages, archaeology (studying old objects), and genealogy (family history).

Scientists are still debating the main ways people arrived in the British Isles. One obvious path was across the narrowest part of the English Channel into Kent. But other routes were also important over time. These include a land bridge that connected Britain to Europe during the Mesolithic period (Middle Stone Age), and sea routes along the Atlantic coasts.

The exact times of the most important migrations are also discussed. For example, when farming started in the Neolithic period (New Stone Age), it brought big changes to the British Isles. This new technology might have been learned by local people from a small number of immigrants, or it could have been brought by colonists who moved in and changed the population a lot.

Other important times when people moved to the British Isles include:

• The Bronze Age and Iron Age, when Celtic languages and new technologies arrived.
• The Roman era.
• The time of the Anglo-Saxons.
• The Viking era.
• The Norman invasion in 1066.
• And even later, during the European wars of religion.

How Scientists Study Genetic History

Scientists use special tools to study the genetic history of people. One of the first big studies was by Luigi Luca Cavalli-Sforza. He looked at tiny differences in proteins found in human blood, like blood groups. He suggested that most of the genetic differences in Europe could be explained by people moving from the southeast (like the Middle East) towards the northwest (like Britain and Ireland). He thought this movement happened when farming began.

Later, scientists started using mitochondrial DNA (mtDNA) to study the female family line. They also used Y chromosome DNA to study the male family line. These types of DNA are special because they only show specific parts of a person's genetic history, helping scientists track how people moved in the past.

In Britain, big projects like the Oxford Genetic Atlas Project (OGAP) and People of the British Isles have collected lots of DNA samples. These projects, often linked to Bryan Sykes and Oxford University, help gather more information about the genetic makeup of the British Isles.

The First People in the British Isles

In 2007, Bryan Sykes wrote a book called Blood of the Isles, based on 6,000 samples from the OGAP project. Another scientist, Stephen Oppenheimer, also used genetic data for his 2006 book, The Origins of the British. Both Sykes and Oppenheimer suggested that many early people came to Britain and Ireland from the Iberian Peninsula (modern-day Spain and Portugal). This idea was largely based on male Y chromosome DNA evidence.

However, by 2010, newer studies with more complete Y DNA data showed something different. They suggested that most of the Y DNA types in Britain arrived more recently. These types came with Celtic and Germanic migrations from Central and Northern Europe during the Bronze Age. Some of the very oldest ancestry, from the Mesolithic period, seems to have come from Scandinavia.

In 2012, a large study of female mitochondrial DNA (mtDNA) found that the oldest female family lines in Europe came from the Middle East. This happened during the Late Glacial Maximum (a very cold period) about 19,000 to 12,000 years ago. These people then spread out from different areas in Europe, including the Franco-Cantabrian region, the Italian Peninsula, and the East European Plain, to repopulate the continent.

Germanic and Scandinavian Ancestry

Scientists have also looked at whether DNA can show signs of Germanic invasions, especially in England. Studies have shown that there are indeed genetic signs of Germanic people moving into England. One study found that "Germanic" genetic markers typically make up 20% to 40% of the DNA in England, with York being an exception at 60%. Most of Scotland showed a similar genetic makeup to England. It was hard to tell the difference between the genetic influence of the Anglo-Saxons and the later Danish Vikings, as their DNA was very similar.

A study on Norwegian Viking ancestry in Britain found specific areas where their DNA is more common. These include Lowland and Eastern Scotland, the North Sea islands of Shetland and Orkney, Western Scotland and the Western Isles, Anglesey in Wales, the Isle of Man, and the Wirral, Mid-Cheshire, West Lancashire, and Cumbria in England.

The Irish Population's Genetic Story

In Ireland, scientists like Dan Bradley have studied the genetics of the population, including how surnames are linked to DNA. Databases are being built for Britain and Ireland, often using personal DNA tests. One interesting study found that in some cases, Irish surname groups were strongly linked to single male family lines. This suggests that these lines might have come from important founding leaders, like Niall of the Nine Hostages.

Since 2010, new technologies can test hundreds of thousands of tiny changes in the rest of our human genome (called autosomal DNA). These large studies have shown that people in Europe are mostly related to their geographical neighbors. This means that people in Britain and Ireland are most genetically similar to people in nearby countries. So far, these studies haven't led to completely new theories about ancient migrations.

It's also been suggested that Y chromosome diversity (male lines) can change faster than the overall population's DNA. This is because sometimes, certain male lines spread more quickly than the general population. This means that the most common Y chromosomes in an area might show more recent "waves" of human movement.

Mitochondrial DNA (Female Lines)

In 2007, Bryan Sykes divided mitochondrial DNA results into twelve main groups, called haplogroups, for different parts of the British Isles. He created maps and ideas about ancient migrations for Ireland, Scotland, Wales, and England.

Sykes and Oppenheimer gave nicknames to these haplogroups to make them easier to remember. Here are some of the main ones found in the British Isles, with their scientific names and popular "clan names":

mtDNA Haplogroups

• Haplogroup H (mtDNA): Helena (Sykes), Helina (Oppenheimer)
• Haplogroup I (mtDNA): Isha
• Haplogroup J (mtDNA): Jasmine
• Haplogroup T (mtDNA): Tara
• Haplogroup V (mtDNA): Velda (Sykes), Vera (Oppenheimer)
• Haplogroup W (mtDNA): Wanda
• Haplogroup X (mtDNA): Xenia
• Haplogroup U (mtDNA): Europa (Oppenheimer)
  • And within U:
    • Haplogroup U2 (mtDNA): Uta
    • Haplogroup U3 (mtDNA): Uma
    • Haplogroup U4 (mtDNA): Ulrika
    • Haplogroup U5 (mtDNA): Ursula

Sykes found that the pattern of female clans (haplogroups) was similar across England. However, there was a clear trend from east and north to the south and west. The smaller clans were mostly found in the east of England.

He also found that Haplogroup H was very common in Ireland and Wales. There were some small differences between North, Mid, and South Wales, with North and Mid Wales being more similar to each other.

Sykes discovered that 10% of the Irish population belonged to Haplogroup U5, nicknamed Ursula. He estimated that this female line entered Ireland around 7,300 BC. Similar old dates were suggested for other mitochondrial haplogroups. This means that many female family lines in Ireland are much older than the arrival of Iron Age Celts. There were only small differences in female clans across the four provinces of Ireland.

Y DNA (Male Lines)

In his 2007 book Blood of the Isles, Bryan Sykes also looked at 6,000 samples from the OGAP project to identify five main Y-DNA groups for the British Isles. Just like with mitochondrial haplogroups, Sykes and Stephen Oppenheimer gave these male groups "clan names" to make them easier to understand. Here are their scientific names:

• Haplogroup R1b (Y-DNA): Oisin (Sykes), Ruisko (Oppenheimer)
• Haplogroup I (Y-DNA): Wodan (Sykes), Ivan (Oppenheimer)
  • The two most important types within I were:
    • I1 (Ian)
    • I2 (Ingert), now called I2b or I2a2
• Haplogroup R1a (Y-DNA): Sigurd (Sykes), Rostov (Oppenheimer)
• Haplogroup E1b1b (Y-DNA): Eshu (Sykes)
• Haplogroup J (Y-DNA): Re (Sykes)

The large Haplogroup R1b (Y-DNA) is very common in Western Europe, including Britain and Ireland. While it was once thought to link the British Isles to Iberia (where it's also common), ideas about its origins have changed. We now know that R1b and R1a came into Europe with Indo-European migrants, likely from the area around the Black Sea. R1 is now the most common male haplogroup in Europe.

The most common type of R1b in England is R1b-S21 ("Germanic"), which is common in North Sea areas like the Netherlands and Denmark. Ireland is mostly dominated by R1b-L21 ("Celtic"), which is also found in northwestern France, the north coast of Spain, and western Norway. However, R1B L21 is also common in England, even more so than other lines. The patterns of these haplogroups are complex and don't always match simple migration ideas. For example, R1a becomes less common further east, while R1b becomes more common. Also, farming led to larger populations, which would have increased R1b in Eastern Europe. The wide variety of eye and hair colors in Europe also suggests older origins linked to ice age climates. These variations in R1b and R1a, including dark-haired R1b individuals and differences like baldness, suggest a more complex and ancient origin.

Haplogroup I is a group of several male lines that are quite different from each other. These might be the only male lines left in Europe from before the Neolithic period. Looking at the three main types:

• I1, is mainly linked to Scandinavia today. It's common in parts of England, especially Eastern England, where it's as frequent as in Scandinavia.
• I2a, is linked to the Balkans and is not common in Britain and Ireland.
• I2b, is not clearly linked to any specific part of Europe.

Haplogroup R1a, which is a distant relative of R1b, is most common in Eastern Europe. In Britain, it's often linked to Scandinavian immigration during the Viking settlements. About 25% of men in Norway belong to this haplogroup, and it's much more common there than in the rest of Scandinavia. Around 9% of all Scottish men have the Norwegian R1a type, and it's found in over 30% of men in Shetland and Orkney. However, there's no definite proof that it only came with Vikings. Similarities could have come from earlier settlement patterns. Today's Scandinavians belong to many different haplogroups.

Haplogroups E1b1b and J in Europe are seen as markers of Neolithic movements from the Middle East to Southern Europe, and likely then to Northern Europe. These haplogroups are most often found in Southern Europe and North Africa. They are rare in Northern Europe. For example, E1b1b is found in 1% of Norwegian men, 1.5% of Scottish, 2% of English, 2.5% of Danish, 3% of Swedish, and 5.5% of German men. It's much more common in places like Kosovo (47.5%) and Greece (30%).

Uncommon Y Haplogroups: Surprising Discoveries

Geneticists have made some surprising discoveries about less common Y haplogroups. For example, seven men with the surname Revis, which comes from Yorkshire, carry a genetic signature previously found only in people of West African origin. All these men belonged to Haplogroup A1a, which scientists believe started in Eastern or Southern Africa. These men don't look African, and there are no old stories or documents suggesting the Revis family has African ancestors. It's thought that this haplogroup might date back to the Roman era, when Africans and Romans of African descent are known to have lived in Britain. According to Bryan Sykes, even though the Romans ruled for a long time, they left only a tiny genetic footprint. The genetics of some visibly white (European) people in England suggest they might be "descended from North African, Middle Eastern, and Roman clans."

The town of Abergele in North Wales has a very high percentage (33%) of haplogroup E1b1b1. This haplogroup is believed to have spread across Europe from the Balkans.

Scientists have also found that former American president Thomas Jefferson, who might have had Welsh ancestors, along with two other British men named Jefferson, carry the rare Y chromosome marker T. This marker is usually found in East Africa and the Middle East. It's also found in 4.5% of Greek men, 3.5% of Estonian, and 2.5% of Spanish and Italian men. There haven't been other documented cases of Haplogroup T in Northern Europe besides these two. However, the presence of different European types within this group suggests that Jefferson's male line could belong to an ancient and rare European type.