A   M91
�       A*   -
�       A1   M31
�       A2   M6, M14, M23, M29/P3/PN3, M49, M71, M135, M141, M196, M206, M212, MEH1, P4, P5, PK1
�      �       A2*   -
�      �       A2a   M114
�      �       A2b   P28
�       A3   M32
�      �       A3*   -
�      �       A3a   M28, M59
�      �       A3b   M144, M190, M220
�      �       �       A3b*   -
�      �       �       A3b1   M51
�      �       �       A3b2   M13, M63, M127, M202, M219, M305
�      �       �      �       A3b2*   -
�      �       �      �       A3b2a   M171
�      �       �      �       A3b2b   M118

NOTES:

• In A2 the designation M29/P3/PN3 means that these three SNPs are identical but were discovered separately. The listing is alphabetical, not necessarily in the order of discovery.

Y-DNA haplogroup A represents the oldest branching of the human Y chromosome tree. Like Y-DNA haplogroup B, the A lineage is seen only in Africa and is scattered widely, but thinly across the continent. These haplogroups have higher frequencies among hunter-gather groups in Ethiopia and Sudan, and are also seen among click language-speaking populations. Their patchy, widespread distribution may mean that these haplogroups are remnants of ancient lineages that once had a much wider range but have been largely displaced by more recent population events.

The most commonly seen sub-groups of haplogroup A are A2 (A-M6), A3b1 (A-M51), and A3b2 (A-M13). Sub-groups A2 and A3b1 are seen in South Africa, with A3b1 seen exclusively among the Khoisan. The range of A3b2 is restricted to Eastern Africa and at lower frequencies among Cameroonians. About 1.1% of African-Americans belong to the sub-group A3b2.

References:

Cinnioglu et al, Excavating Y-chromosome Haplotype Strata in Anatolia. (pdf) Human Genetics. 114:127-148, 2004.
Cruciani et al, A Back Migration from Asia to Sub-Saharan Africa Is Supported by High-Resolution Analysis of Human Y-Chromosome Haplotypes. (pdf) American Journal of Human Genetics, 70:1197-1214, 2002.
Deng et al, Evolution and Migration History of the Chinese Population Inferred from the Chinese Y-chromosome Evidence. (pdf) Journal of Human Genetics, 49:339-348, 2004.
Mohyuddin et al, Detection of Novel Y SNPs Provides Further Insights into Y Chromosomal Variation in Pakistan. Journal of Human Genetics, 2006.
Semino et al, Ethiopians and Khoisan Share the Deepest Clades of the Human Y-Chromosome Phylogeny. (pdf) American Journal of Human Genetics, 70:265-268, 2002.
Shen et al, Reconstruction of Patrilineages and Matrilineages of Samaritans and other Israeli Populations from Y-Chromosome and Mitochondrial DNA Sequence Variation. (pdf) Human Mutation, 24:248-260, 2004.
Valone et al, Y SNP Typing of African-American and Caucasian Samples Using Allele-Specific Hybridization and Primer Extension. (pdf) Journal of Forensic Science, 49:4, July 2004.

Corrections/Additions made since 20 December 2006:

• New Contact Person added 12 January 2007.
• Added Notes section on 17 October 2007.

Contact Person for Haplogroup A: Ana Oquendo Pabon

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