Haplogroup A is the foundation from which all other haplogroups spring and
is therefore the oldest. It is thought to have arisen about 338,000 years ago,
with a 95% confidence level of 237,000 to 548,000 years. It originated in
Africa, perhaps pre-dating the development of anatomically modern homo sapiens sapiens.
Unlike other haplogroups, its parent is unknown
Its immediate child, BT (characterized by M42), is descended from the A2-T subclade but has not
been found in modern populations.
Its next-generation offspring are B (characterized by M181), with living representatives, and
CT, which gave rise to other haplogroups but also has no living