Mitochondrial DNA implies that nearly all modern dogs fall into just one of 4 monophyletic haplogroups which might be named haplogroups A, B, C, and D. Nearly all dogs drop in just haplogroup A. The mDNA "molecular clock" implies that 22,800 YBP the initial genetic divergence (break up) happened in haplogroup A, causing the lineages A1b and A2. Thi