MtDNA haplotype sharing between dog breeds and world regions. Thirteen breeds for which at least 10 individuals were typed are included. Squares represent world regions and state haplotypes observed therein. Figures inside brackets indicate the number of breeds where the particular haplotype was observed. Circles contain haplotypes shared between breeds from different regions; numbers enclosed in parenthesis are to be read from right top to left down, and correspond to the number of breeds in which a haplotype is observed in each continental region. For example, "A18 (3:1:1)" indicates that haplotype A18 was found in 3 European, 1 Asian and 1 Middle-Eastern breeds.