Fig 1. Population structure of cat breeds via principle component analysis (PCA).

The first two principle components (PC1 and PC2) explain majority of the genetic variation among cat breeds. (a) A broad overview of the population structure of all breeds. Each individual cat is represented by a circle that is colored according to its ancestral group (Western-red, “Middle”-yellow, Eastern-blue) and dashed boxes are used to designate 9 Western breeds (left box), 11 intermediate breeds (middle box) and 6 Eastern breeds (left box). The blue dots extending to the “Middle” and Western groups belong to Bombay breed. Note that Bombay breed is formed by breeding of Burmese and American Shorthair. (b-d) Individual representations of Western, “Middle”, and Eastern breeds, respectively. Note the separation of the interspecies hybrid breed, Bengal, from other “Middle” breeds in (b) and separation of the phenotypically distinct Birman from other Eastern breeds in (c). Six Bombay individuals were outside of the ancestral grouping of Eastern breeds were removed in (d) for ease of presentation.