A simplified diagram of dog evolutionary history. Blue (wolf) and green (village dog) arrows represent separate evolutionary lineages, each one containing population substructure largely resulting from isolation by distance among local populations. Red arrows (breeds) represent an ancient (far left) and three modern breeds. Green/blue bar and arrows depict one (but possibly more) domestication events from Eurasian wolves followed by some small degree of localized dog-wolf introgression. Red/green bars depict founders from one or more breeds being drawn from village-dog populations, with a red horizontal arrow at the present time to show admixture with descents of breed dogs contaminating the gene pool of some village-dog populations. As globalization and modernization continue, these breed-descended migrants will become an even larger threat to the reservoirs of indigenous dog diversity.
Boyko Genome Biology 2011 12:216 doi:10.1186/gb-2011-12-2-216