---
title: "Dodecad K12b explained: the twelve components and what Gedrosia actually is"
description: "The original admixture project's most-used calculator: what the twelve K12b components are anchored to, what Gedrosia and Caucasus mean in modern ancient-DNA terms, and how to read a K12b breakdown."
canonical: https://www.ancestrify.io/blog/dodecad-k12b-explained
date: 2026-08-31T08:16:00+00:00
author: "Andi Thomaj"
---

# Dodecad K12b explained: the twelve components and what Gedrosia actually is

Dodecad is where all of this started. Dienekes Pontikos — a pseudonymous Greek blogger — launched
the project in 2010, built calculators on the academic
[ADMIXTURE software](/blog/admixture-software-explained), and released his DIY tooling publicly.
Every other project on GEDmatch — [Eurogenes](/blog/eurogenes-k13-explained),
[HarappaWorld](/blog/harappaworld-calculator-explained), MDLP, puntDNAL — descends from that
tooling. "Dodecad" is Greek for a group of twelve, and K12b, the project's most-used calculator,
is the twelve-component model this post reads.

## The twelve components

Gedrosia · Caucasus · North European · Atlantic Med · Southwest Asian · Northwest African ·
East African · Sub-Saharan · South Asian · East Asian · Southeast Asian · Siberian.

As always in this family, the names mark where each statistical profile peaks in the training
references, not places anyone's ancestors verifiably lived. Three of them deserve their own
paragraphs, because K12b's readers spend most of their confusion on the same three.

**Gedrosia** — named for the ancient region spanning today's southern Pakistan and Iran — peaks in
Baloch and Brahui references. It is nearly the same statistical object as HarappaWorld's "Baloch"
component. In modern ancient-DNA language, the ancestry it tracks is Iranian-plateau-related —
the broad ancestry stream that also spread with early farming toward South Asia. West Europeans
carry a real slice of it (roughly ten points in some populations), which puzzled everyone in
2011; the ancient samples published since locate the source in steppe-related ancestry's own
Caucasus-adjacent half, which K12b — built before those genomes existed — has no way to name.

**Caucasus** peaks where it says, and in 2011 it looked like a fog covering everything from
Anatolia to Iran. Ancient DNA later split that fog into Caucasus hunter-gatherer and
Iranian-related components; K12b's Caucasus blends them plus the Anatolian farmer legacy of the
region. A large Caucasus score in a West Asian or southeast European profile is expected
background, not evidence of ancestors in Georgia.

**Atlantic Med** peaks in Sardinians and Basques — the living populations richest in
[early European farmer ancestry](/blog/neolithic-farmer-ancestry-explained). Read it as the
farmer layer, with the same caution as everything here: the calculator predates the ancient
genomes that proved what the component was tracking.

## Reading a K12b breakdown

The mechanics are the family's: an optimiser distributes your genome across twelve fixed
profiles, always sums to 100%, attaches no error bars, and
[cannot reject a wrong panel](/blog/what-is-an-admixture-calculator). The K12b-specific advice:

- **North European + Atlantic Med + Caucasus + Gedrosia is the West Eurasian quartet.** Most
  European profiles are some blend of the four; the *ratios* are the informative part, and they
  track the deep layers (hunter-gatherer, farmer, steppe) better than any single number does.
- **Southwest Asian** is modal in Arabia; moderate values through the Mediterranean and Horn of
  Africa are ordinary. **Northwest African** at a few percent in Iberia is likewise expected.
- **Trace East Asian / Siberian / Amerindian-adjacent slivers** in West Eurasian profiles are
  noise or very old shared ancestry — not a recent ancestor. K12b has no mechanism to tell you
  which, and [neither does any calculator](/blog/how-accurate-are-admixture-calculators).
- **Compare within the calculator, not across.** The same genome scores differently in K12b and
  HarappaWorld's similarly named components (a British kit runs ~44% North European in K12b but
  ~51% NE-Euro in HarappaWorld) because the components are anchored differently —
  [why calculators disagree](/blog/why-admixture-calculators-disagree) covers the mechanics.

## The Oracle, and what replaced all this

K12b pairs with the [Oracle utilities](/blog/gedmatch-oracle-explained) — Dienekes wrote the
original Oracle — which rank the project's reference populations by distance from your component
profile. That ranking is the most interpretable thing a Dodecad run produces.

Fifteen years on, the exploration K12b pioneered runs against dated ancient reference panels
instead of component constructs: era-scoped
[Global25 admixture calculators](/lab/admixture), a
[closest-populations distance ranking](/lab/g25-distance), and a
[PCA view](/lab/g25-pca) of your coordinate among published ancient samples, free and in the
browser. And when a component score graduates into a claim about descent, the tool with a test
attached is a [formal qpAdm model](/qpadm) — the method that can say no, which no Dodecad
descendant ever could.

Terms used here are defined in the [glossary](/glossary).