Haplogroup A (Y-DNA)

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Haplogroup A
Time of origin
Place of origin	Africa
Ancestor	Y-chromosomal Adam
Descendants	A1
Defining mutations	M91
Typical members	Khoisan, Bushmen, Sudanese

In human genetics, Haplogroup A (M91) is a Y-chromosome haplogroup.

Haplogroup A is common among Bushmen.

Haplogroup A is localized mainly to Southern Africa with a small to notable presence among a few populations in East Africa. It represents the oldest and most diverse of the human Y-chromosome haplogroups. It is believed to be the haplogroup corresponding to Y-chromosomal Adam.

1 Distribution
2 Subclades
- 2.1 A3b2
- 2.2 A1
3 References
4 External links

[edit] Distribution

Haplogroup A is common among the Khoisan people such as the Bushmen, which - together with its high diversity - suggests that it is perhaps their original ancestral haplogroup. For example, Knight et al. (2003) report a 12-44% presence of haplogroup A in various Khoisan tribes. Surprisingly, this particular haplogroup was not found in a sample of the Hadzabe from Tanzania, a population traditionally considered an ancient remnant of Khoisans due to the presence of click consonants in their language.

Semino et al. 2001 found haplogroup A in 10.3% of an Oromo sample and 14.6% of an Amhara sample from Ethiopia. Especially high frequency (41%) can be found in Ethiopian Jews (Cruciani et al. 2002) and important percentages are also shared by Bantus from Kenya (14%, Luis et al. 2004), a small sample of Iraqw from Tanzania (17%, Knight et al. 2003), and Fulbe from Cameroon (12%, Cruciani et al. 2002). The highest presence of haplogroup A in East Africa, however, was discovered in a sample of the Sudanese population: 42.5% (Underhill et al. 2000).

[edit] Subclades

[edit] A3b2

It must be noted, however, that the subclade found in East Africa (A3b2) is different from those found in the Khoisan samples and only remotely related to them (it is actually only one of many subclades within haplogroup A). This finding suggests an ancient divergence of certain A-carrying East African groups from the same ancestral population in the south.

[edit] A1

In 2007, seven men from Yorkshire, England sharing a distinctive surname were identified as being from the A1 subgroup of haplogroup A. It was discovered that these men had a common male-line ancestor from the 18th century, but no previous information about African ancestry was known. The A1 subgroup is extremely rare. In addition to the seven Yorkshire men, only 25 living carriers of the A1 subgroup are known, all of West African ancestry. ^[1]