R-S20045

Overview

This page describes the R-S20045 haplogroup, a rare branch of the R-U106 tree that links the ancient North Sea Germanic world to later lowland Scots families such as the Glasgows.

FamilyTreeDNA Discover places R-S20045 as a descendant of R-Z17 on the R-U106 branch. R-Z17 likely branched from its parent around 2000 BCE and has thousands of modern descendants across Scandinavia and northern Europe. R-S20045 forms only one of several Z17 sub-branches and remains much rarer than most of its siblings.

Discover currently gives R-S20045 a formation age in the early second millennium BCE and a much younger common ancestor for modern testers that sits around the middle of the first millennium BCE. The McDonald phylogeography paper gives a TMRCA for R-S20045 of about 251 BC with a 95% range from 851 BC to 234 AD. In the Glasgow project timeline, we treat circa 250 BCE as the working date for the ancestor who links all known R-S20045 lines.

R-S20045 shows a long, quiet stretch on the tree with very few known branches compared to other Z17 clades. This pattern points to a strong genetic bottleneck. For many centuries only a small number of men seem to have carried this line forward. Later offshoots such as R-S14827, R-FT4811 and R-FT32941 produced the modern families that appear in the Glasgow Surname DNA Project.

Position within the R-Z17 Tree

A simplified path from R to the Glasgow cluster looks like this:

• R-M269
• R-U106
• R-Z18
• R-Z17
• R-S20045 (bottleneck ancestor, working date ~250 BCE)
• R-BY139800
• R-S14827
• R-FT4811
• R-FT32941
• R-FT25406
• R-FT20271
• R-FTE32242 and related surname-era branches

R-S20045 therefore sits at the root of the "Glasgow branch" of R-U106, and also feeds several non-Glasgow lines in Scandinavia and elsewhere.

Historical Context: The Iron Age Bottleneck

The working date for the R-S20045 common ancestor falls in the Pre-Roman Iron Age in northern Europe. This period matches several key features that help explain the bottleneck.

• Climate stress in northern Europe affected harvests. Pollen and peat-bog studies show wetter and colder conditions in Jutland and southern Scandinavia in the late Iron Age. Population levels dipped in some regions as marginal farmland turned into bog or rough pasture.
• The Jastorf Culture dominated northern Germany and southern Denmark in the early Iron Age. Archaeologists treat Jastorf as an early Germanic culture that fed into later North Sea Germanic groups.
• Early Germanic groups interacted with tribal confederations such as the Cimbri and Teutones that Roman writers described. These groups drew recruits from the same broad cultural zone that carried Z17 and its descendants.

The long, thin branch for R-S20045 suggests that the Glasgow ancestral line survived this period inside a relatively small kin group somewhere in the wider Jastorf or post-Jastorf region. Other U106 branches expanded toward the Roman frontier at the same time. R-S20045 remained on the northern and north-eastern side of that movement.

Cultural and Geographic Affiliations

Upstream R-Z17 has clear ties to Scandinavia and the North Sea coasts. Modern R-Z17 descendants concentrate in Sweden, Norway, Denmark, northern Germany, the Netherlands and the British Isles. Ancient DNA under nearby Z17 subclades links this cluster to:

• Viking Age burials at Sigtuna in Sweden.
• Viking Age and late Iron Age burials in coastal Norway and Denmark, such as the sample that FTDNA labels Nordland 1502 in its Ancient Connections list.

No ancient skeleton has yet tested positive for R-S20045 itself, although this can change as new remains enter the databases. The neighbors of R-S20045 on the Z17 tree already appear in Viking Age contexts across Scandinavia and the wider North Sea zone.

Taken together, these lines of evidence support the following working picture for R-S20045:

• It belongs to the northern Germanic core within R-U106.
• The early R-S20045 men probably lived in southern Scandinavia or the Jutland–Schleswig region.
• They remained outside the Roman provincial sphere and took part in the tribal world that Roman sources encountered along the north European frontier.

Later branches under S20045, especially R-S14827 and R-FT4811, moved into the British Isles during or after the Migration Period and the Viking Age.

Genetic Rarity and the Bottleneck Pattern

The McDonald phylogeography paper notes that R-S20045 has very few modern representatives in large U106 datasets. It lists R-S20045 with low counts when compared with other Z17 subclades. It also notes that almost all usable geographic information for this branch comes from the downstream R-S14827 level.

FamilyTreeDNA Discover describes R-S20045 as a rare line within a much larger Z17 cluster that has several thousand tested men. The Discover statistics show only a few dozen known R-S20045 descendants spread across a small set of countries.

This pattern fits a story where:

• One small extended family carried R-S20045 through the late Iron Age.
• That family produced a few distinct branches at the R-S14827 and R-BY139800 level.
• Most later expansion took place through those downstream branches rather than through a wide spread at the S20045 root.

The Glasgow Surname DNA Project sits inside this narrow channel of survival.

Descendant Analysis

Z17 > S20045 > S14827 > FT4811 > FT32941 > FT25406 > FT20271 View source illustration

The R-S20045 tree divides into two broad stories:

1. One story covers the Scandinavian sister lines that remained inside Scandinavia or its near neighbors.
2. The other story covers the migrant lines that moved into Britain and eventually produced the Glasgow, Churnside, Brown and Wright families.

1. Scandinavian Sister Lines under S20045

Downstream branches such as R-BY139800 and R-S14827 carry men who still live in Scandinavia and who show clear Scandinavian origins in their earliest known paternal lines.

One important branch is R-BY136156 under R-S14827. Project work links this to families in Denmark and Sweden. The Jørgensen project at FTDNA, for example, lists a tester from Denmark under R-BY136156. The Glasgow Ancient YDNA page records:

• Julius Christian Jørgensen (1816–1884) from Denmark (R-BY136156).
• Lars Andersson (born about 1700) in Sweden (R-BY136156).

These lines give a good picture of the "stay-at-home" side of S20045. They show that close cousins of the Glasgow ancestors remained in Scandinavia through the Viking Age and into the early modern period.

2. The Migrant Line toward Britain (The Glasgow Path)

A second set of branches under R-S20045 left the Scandinavian homeland and moved into the North Sea frontier. The key waypoints for this migrant line are:

• R-S14827 (~350 CE)
  • A Migration Period ancestor that links the Scandinavian S20045 cluster to Britain.
  • The earliest geography for this subclade points toward the North Sea region and the later Danelaw.

• R-FT4811 (~1000–1050 CE)
  • The "lowland Scots progenitor" in the project model.
  • Likely location near Chirnside in Berwickshire or nearby parishes in the Scottish Borders.
  • Connected to the surnames Churnside, Brown, Wright and Glasgow.

• R-FT32941 (~1050–1150 CE)
  • A node that links the Borders origin to the later Glasgow surname cluster.
  • Project notes explore a possible medieval link with a Duffield branch in northern England.

• R-FT25406 (~1400–1450 CE)
  • The main "Glasgow progenitor" level for the surname era.
  • Associated with lowland Scots Glasgows in Renfrewshire and the Glasgow area.
  • Includes colonial descendants such as Jeremiah Glasgo (abt.1713–1777).

• R-FT20271 (~1550–1600 CE)
  • The Scots–Irish and colonial American branch.
  • Anchored around Robert Glasgow (1749–1836) and related Ulster and American lines.

The R-FT4811 page describes the later details of these families. For R-S20045, the main point is that every one of these men carries a Y-chromosome that traces back through R-S14827 and R-BY139800 to the small Iron Age family that first carried R-S20045.

Key People and Project Anchors

Although R-S20045 itself dates to the Iron Age, we know it today through much later men who sit on its descendant branches. Some of the anchor figures in the Glasgow Ancient YDNA work are:

• Julius Christian Jørgensen (1816–1884) in Denmark (R-BY136156, Scandinavian sister line).
• Lars Andersson (born about 1700) in Sweden (R-BY136156, Scandinavian sister line).
• William Thomas Wright (1843–) in Bethnal Green and Shadwell, Middlesex, England (R-FT4811, non-Glasgow British branch).
• Alexander Churnside (1838–abt.1873) in Saint Mary, Jamaica, with a probable origin in Chirnside, Berwickshire (R-FTA30932 under R-FT4811).
• Jeremiah Glasgo (abt.1713–1777) and Robert Glasgow (1749–1836) in the Glasgow and Ulster clusters (R-FT25406 and R-FT20271).

These men sit on different twigs of the same tree. Their lines help us sketch the route from an Iron Age bottleneck in the Jastorf world to lowland Scots families, colonial Ulster Scots and the modern Glasgow diaspora.

Working Model for R-S20045 and the Glasgow Lineage

The Glasgow project currently uses the following model for R-S20045.

1. The R-S20045 common ancestor lived around 250 BCE somewhere in the wider Jastorf or post-Jastorf zone in northern Germany, Denmark or southern Scandinavia.
2. His descendants preserved this line through a bottleneck that lasted several centuries.
3. One branch developed into R-BY139800 and R-S14827 and produced:
   • Scandinavian lines such as R-BY136156 in Denmark and Sweden.
   • A migrant branch that moved into the North Sea frontier and then into the Scottish Borders.
4. That migrant branch formed R-FT4811 around 1000–1050 CE in or near Berwickshire and then:
   • Sent one line west toward Glasgow, which became the Glasgow surname cluster under R-FT32941, R-FT25406 and R-FT20271.
   • Left other cousins in England (Wright) and in the Borders and Jamaican (Churnside and Brown) branches under R-FTA30932.

New Big Y results or new ancient DNA can refine this model. At present it fits the Discover tree, the McDonald phylogeography work and the distribution of known R-S20045 and R-S14827 descendants.

See Also

• Glasgow Ancient YDNA
• R-S14827
• R-FT4811
• R-FT32941
• R-FT25406
• R-FT20271