Schematic representation of mtDNA phylogenetic tree of Native American haplogroups A2 and B2 and immediate Siberian-Asian sister clades (A2a, A2b, A4a, A4b and A4c). Coalescent age calculated in thousand years (ky) as per the slow mutation rate of Mishmar et al.  and as per calibrated mutation rate of Soares et al.  are indicated in blue and red color respectively. The founder age wherever calculated are italicized. The geographical locations of the samples are identified with colors. For more details see complete phylogenetic reconstruction in additional file 2 (panels A-B) and additional file 3.