Mitochondrial DNA signifies that just about all modern dogs slide into one of four monophyletic haplogroups which are named haplogroups A, B, C, and D. Many dogs fall in just haplogroup A. The mDNA "molecular clock" implies that 22,800 YBP the very first genetic divergence (break up) happened in haplogroup A, causing the lineages A1b and A2. This t