Alans were a tribal group of Sarmatians. The subgroup of G2a to which the Alans belonged was actually also found in Central Asia. There are even theories that this subgroup of G2a was brought to Caucasus by Alans. Alanic burials on the Don River were by majority G2a.
Alans were diverse in some Haplogroups. G2a beeing more dominant in Caucasus and Western Alans can be explained with bottleneck effect.

