pups had been produced from two of the original hybrids. At the same time, despite the six F1's successful delivery from the same coyote, they were not all full siblings because multiple sperm from eight different northwestern wolves were used in their production. The successful production of the F2 litter, nonetheless, confirmed that hybrids of coyotes and northwestern wolves are just as fertile as hybrids of coyotes to eastern and red wolves. Both the F1 and F2 hybrids were found to be phenotypically intermediate between the western gray wolves and coyotes. Unlike the F1 hybrids, which were produced via artificial insemination, the F2 litter was produced from a natural breeding. The study also discovered through sequencing 16S ribosomal RNA encoding genes that the F1 hybrids all have an intestinal microbiome distinct from both parent species, but which was once reported to be present in some gray wolves. Moreover, analysis of their complementary DNA and ribosomal RNA revealed that the hybrids have very differential gene expressions compared to those in gray wolf controls. Coydogs Hybrids between coyotes and domestic dogs have been bred in captivity, dating to pre-Columbian Mexico. Other specimens were later produced by mammal biologists mostly for research purposes. Domestic dogs are included in the gray wolf species. Hence, coydogs are another biological sub-variation of hybrids between coyotes and gray wolves - the dog being considered a domesticated subspecies of Canis lupus. See also Canid hybrid Coydog Dingo-dog hybrid Jackal-dog hybrid Wolfdog References Further reading External links Canid hybrids Coyotes Wolves