GigaBautista
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Great question — and you’ve landed on one of the most misunderstood topics in population genetics.
People often *think* Finns are “distant” from other Europeans because of their **Siberian/Eastern Eurasian admixture**, but that’s only a *small* part of the story.
The *real* reason Finns have elevated FST from other Europeans is NOT the Siberian ancestry.
It’s something else entirely — and Azeris/Turks don’t share that history, which is why they don’t show the same inflation.
Let’s break it down cleanly:
---
#
**1. Finns have unusually high genetic drift — *much more than Turks or Azeris***
This is the big one.
Finns went through:
* **small founder populations**
* **isolation in the far north**
* **bottlenecks**
* **high endogamy in earlier periods**
* **late settlement of much of Finland (~2,000 years ago)**
* **small effective population size for long stretches**
This produces **massive drift**, which inflates FST values across the board — even with genetically close groups like Swedes.
###
Key point:
**FST inflation is mainly about drift, not admixture proportions.**
---
#
**2. Turks and Azeris have *low drift* because of huge population size + massive gene flow**
Turkish and Azeri populations historically experienced:
* **large effective population sizes**
* **continuous migration across Anatolia, Iran, Caucasus, Central Asia**
* **huge gene flow from multiple directions**
* **no severe long-term bottlenecks**
Their genomes integrate West Eurasian, Anatolian, Caucasian, and varying Central Asian components — but with **very low drift**.
This makes their FST with Europeans **surprisingly low**, despite notable non-European ancestry.
### Example:
A population with **10% East Asian ancestry but low drift** can have lower FST with Europeans than
a population with **5% East Asian ancestry but high drift**.
And Finns fall strongly into the second category.
---
#
**3. The “Eastern Eurasian ancestry” explanation is mainly *folk genetics***
Finns do have:
* ~5–10% Siberian-related ancestry (Nganasan-like)
But this small admixture alone cannot increase FST much.
FST responds strongly to:
* founder effects
* genetic isolation
* drift
…and only slightly to ~5–10% out-group ancestry.
So that popular explanation (“Finns are more distant because of Siberian blood”) is **oversimplified**.
---
#
**4. Why Finns show inflated FST with other Europeans**
Let’s list the real causes:
### ✔ High drift
### ✔ Bottlenecks
### ✔ Small historical population
### ✔ Frontier isolation
### ✔ Late demographic expansion
These make Finns “stick out” in PCA plots and inflate FST values.
The Siberian ancestry is real — but it’s not the heavy hitter here.
---
#
**5. Why Turks and Azeris do *not* show inflated FST with Europeans**
Because despite having **more non-European ancestry than Finns**, they have:
* **much lower drift**
* **long-term mixing across a huge West Eurasian region**
* **large population sizes**
→ Their FST sits comfortably close to many European populations.
This is why Turks can show:
* Low FST with Southeast Europeans
* Moderate FST with East or West Europeans
* *No inflated values* like Finns have
Even though they have Central Asian–related ancestry in the 5–20% range.
---
#
**TL;DR Summary**
**Finns look genetically distant from Europeans in FST because of *drift*, not because of Eastern Eurasian ancestry.**
Meanwhile:
* **Turks and Azeris** have *more* Asian-related ancestry than Finns
* BUT have *much lower drift*
→ Therefore they show **lower FST** with Europeans overall.
FST ≠ admixture proportion
FST ≠ ancestry type
FST = mostly **drift + effective population size**
In other words, the "muh Turkic ancestry" argument won't fly from now on. Not that it ever did.
@Nectar
@decadouche57
People often *think* Finns are “distant” from other Europeans because of their **Siberian/Eastern Eurasian admixture**, but that’s only a *small* part of the story.
The *real* reason Finns have elevated FST from other Europeans is NOT the Siberian ancestry.
It’s something else entirely — and Azeris/Turks don’t share that history, which is why they don’t show the same inflation.
Let’s break it down cleanly:
---
#
**1. Finns have unusually high genetic drift — *much more than Turks or Azeris***This is the big one.
Finns went through:
* **small founder populations**
* **isolation in the far north**
* **bottlenecks**
* **high endogamy in earlier periods**
* **late settlement of much of Finland (~2,000 years ago)**
* **small effective population size for long stretches**
This produces **massive drift**, which inflates FST values across the board — even with genetically close groups like Swedes.
###
Key point:**FST inflation is mainly about drift, not admixture proportions.**
---
#
**2. Turks and Azeris have *low drift* because of huge population size + massive gene flow**Turkish and Azeri populations historically experienced:
* **large effective population sizes**
* **continuous migration across Anatolia, Iran, Caucasus, Central Asia**
* **huge gene flow from multiple directions**
* **no severe long-term bottlenecks**
Their genomes integrate West Eurasian, Anatolian, Caucasian, and varying Central Asian components — but with **very low drift**.
This makes their FST with Europeans **surprisingly low**, despite notable non-European ancestry.
### Example:
A population with **10% East Asian ancestry but low drift** can have lower FST with Europeans than
a population with **5% East Asian ancestry but high drift**.
And Finns fall strongly into the second category.
---
#
**3. The “Eastern Eurasian ancestry” explanation is mainly *folk genetics***Finns do have:
* ~5–10% Siberian-related ancestry (Nganasan-like)
But this small admixture alone cannot increase FST much.
FST responds strongly to:
* founder effects
* genetic isolation
* drift
…and only slightly to ~5–10% out-group ancestry.
So that popular explanation (“Finns are more distant because of Siberian blood”) is **oversimplified**.
---
#
**4. Why Finns show inflated FST with other Europeans**Let’s list the real causes:
### ✔ High drift
### ✔ Bottlenecks
### ✔ Small historical population
### ✔ Frontier isolation
### ✔ Late demographic expansion
These make Finns “stick out” in PCA plots and inflate FST values.
The Siberian ancestry is real — but it’s not the heavy hitter here.
---
#
**5. Why Turks and Azeris do *not* show inflated FST with Europeans**Because despite having **more non-European ancestry than Finns**, they have:
* **much lower drift**
* **long-term mixing across a huge West Eurasian region**
* **large population sizes**
→ Their FST sits comfortably close to many European populations.
This is why Turks can show:
* Low FST with Southeast Europeans
* Moderate FST with East or West Europeans
* *No inflated values* like Finns have
Even though they have Central Asian–related ancestry in the 5–20% range.
---
#
**TL;DR Summary****Finns look genetically distant from Europeans in FST because of *drift*, not because of Eastern Eurasian ancestry.**
Meanwhile:
* **Turks and Azeris** have *more* Asian-related ancestry than Finns
* BUT have *much lower drift*
→ Therefore they show **lower FST** with Europeans overall.
FST ≠ admixture proportion
FST ≠ ancestry type
FST = mostly **drift + effective population size**
In other words, the "muh Turkic ancestry" argument won't fly from now on. Not that it ever did.
@Nectar
@decadouche57
