Haplogroup A · Ancient Lineage
Haplogroup A
Explore some of the deepest surviving branches of the human Y-chromosome tree.
Approximate region of emergence
Africa; proposals centre on Central-West Africa (Cameroon region) and Southern/Eastern Africa
Estimated time depth
Root branches estimated between roughly 200,000 and 300,000 years before present
Ancestral parent lineage
Y-chromosomal Adam (root of the surviving human Y tree)
Major descendant branches
A00 · A0 · A1a · A1b1 (A-M32 derived) · A1b1b2b (A-M13)
Overview
What this lineage represents
Haplogroup A sits at or near the root of the human paternal tree. Its branches separate earlier than any other surviving Y-chromosome lineage, which is why researchers use it to anchor estimates of when the most recent common paternal ancestor of living men lived.
A is not a single population. It is a set of deeply divergent branches — A00, A0, A1a and A1b — that split from one another tens of thousands of years apart and are today found in very different parts of the continent.
Because these branches are rare and geographically scattered, each new sampling study can shift how the top of the tree is drawn. Treat the structure below as the current consensus, not a closed question.
Lineage tree
From parent lineage to modern descendants
Select any node to read its estimated age, parent lineage, regions and descendant branches.
Ancient distribution
Where early carriers are believed to have lived
Early carriers of A branches are inferred to have lived in scattered forager populations across the continent. The geographic split between the deepest branches — Central-West Africa on one side, Southern and Eastern Africa on the other — is the main reason researchers disagree about where the root lies. Ancient DNA from southern Africa confirms deep divergence in the region, while the discovery of A00 in Cameroon points to comparable depth in the west.
Migration
Origin → Expansion → Migration → Modern distribution
Origin
~300,000–200,000 ybp
Deep divergence
The earliest splits in the surviving paternal tree occur within Africa, long before any expansion out of the continent.
Expansion
~100,000–50,000 ybp
Regional isolation
Branches become geographically separated, with distinct clusters forming in Central-West, Southern and Eastern Africa.
Migration
~35,000–10,000 ybp
Nile and Sahel corridors
A-M13 spreads along the Nile Valley and westwards into the Sahel; A-M51 remains concentrated in the south.
Modern
Last 3,000 years
Displacement and absorption
Later farming and herding expansions reduce the relative frequency of A branches in many regions, leaving them as minority lineages outside Khoe-San and some Nilotic populations.
Estimated pathways
Modern distribution
Where major branches are documented today
West Africa
A1a (A-M31)
Low frequency in Guinea-Bissau, Mali and Senegambia.
Central Africa
A00, A0
Rare; documented in specific Cameroonian communities.
East Africa
A-M13
Moderate frequency in Nilotic and Sudanic populations.
Southern Africa
A-M51, A-M14
Frequently observed among San and Khoe populations.
North Africa
A1a, A-M13
Very low frequency; linked to trans-Saharan contact.
African Diaspora
A00, A1a, A-M13
Observed at low frequency in the Americas and the Caribbean.
Outside Africa
A1a
Rare reports in the Near East and southern Europe.
Major subclades
Downstream branches
| Branch | Marker | Regions | Note |
|---|---|---|---|
| A00 | A00 | Cameroon | Deepest known surviving branch; extremely rare. |
| A0 | A0 | Central-West Africa | Early branch sister to A0-T. |
| A1a | A-M31 | Sahel, Senegambia | West African branch. |
| A1b1a | A-M51 | Kalahari | Southern African branch. |
| A1b1b2b | A-M13 | Sudan, Ethiopia, Kenya | East African / Nile Valley branch. |
Populations
Frequently observed in
These are populations in which particular branches have been reported. Each of them carries several paternal lineages; the listed branches are not a definition of the group.
Ju|'hoansi
Southern Africa
A-M51, B-M112
!Xun
Southern Africa
A-M51, A-M14
Dinka
East Africa
A-M13, B-M60
Nuer
East Africa
A-M13
Mandinka
West Africa
A-M31, E-M2
Mbo
Central Africa
A00, E-M2
A haplogroup traces one unbroken father-to-son line. It says nothing about the rest of a person's ancestry, and it is not a marker of ethnicity or identity.
Research notes
Where the science is still unsettled
- Where the root of the human Y tree lies geographically is unresolved. Central-West African and Southern African origins both have support.
- A00 was described only in 2013; further deep branches may still be undiscovered in undersampled regions.
- Age estimates depend on the mutation rate model used and can shift by tens of thousands of years between studies.
Citations for this lineage
- Cruciani, F. et al. (2011). A revised root for the human Y chromosomal phylogenetic tree: the origin of patrilineal diversity in Africa. American Journal of Human Genetics
- Mendez, F. L. et al. (2013). An African American paternal lineage adds an extremely ancient root to the human Y chromosome phylogenetic tree. American Journal of Human Genetics
- Karafet, T. M. et al. (2008). New binary polymorphisms reshape and increase resolution of the human Y chromosomal haplogroup tree. Genome Research
- Batini, C. et al. (2011). Signatures of the pre-agricultural peopling processes in Sub-Saharan Africa as revealed by the phylogeography of early Y chromosome lineages. Molecular Biology and Evolution
- Schlebusch, C. M. et al. (2017). Southern African ancient genomes estimate modern human divergence. Science
- Poznik, G. D. et al. (2016). Punctuated bursts in human male demography inferred from 1,244 worldwide Y-chromosome sequences. Nature Genetics
Continue exploring
Early African Lineage
Explore ancient paternal branches found among populations across Central, Eastern and Southern Africa.
CCoastal Aboriginal Lineage
One of the earliest lineages to leave Africa, carried along the southern coastal route to Arabia, South Asia, Australia and the Americas.
DDeep Relative Of E
The sister branch of haplogroup E within DE, today found in Tibet, Japan and the Andaman Islands, with rare deep African branches.
EThe African Macro-Lineage
Originated in Africa, yet the oldest indigenous paternal lineage in the Levant and Arabia as well; the most frequently observed paternal lineage in Africa and its diaspora; parent of both E1a and E1b.
E1aAfrican Expansion
A deep paternal lineage that traces an African origin through the Green Sahara, the Mediterranean world, and into the Sahel and West African empires.
E1bAfrica & Beyond
Explore a highly diversified lineage with branches distributed throughout Africa and neighbouring regions.
FRoot Of Most Non-African Lineages
The lineage from which G through T descend, accounting for the overwhelming majority of men outside Africa.