Coyote-dog hybrids, or coydogs, are produced by crossing coyotes with dogs. Coyote-dog hybrids can occur in the wild, usually in areas where the coyote range is expanding and other coyotes are hard to find. Natural hybridizations are uncommon, however, because the breeding cycles of dogs and coyotes are not synchronized. Organized breeding programs to produce coydogs exist, but are similarly rare. Some states in the US ban such hybrids as pets because of the unpredictable temperament of the animals.
The VGL coyote-hybrid test consists of 2-4 types of assays (depending on whether animals are female or male) and analyses: Y-chromosome haplotype, coyote-specific DNA markers and population analysis of DNA markers. Below is a more detailed description.
- Males are tested with markers linked to the Y-chromosome and results are compared to our database of known coyote and dog haplotypes. The Y-chromosome is transmitted from fathers to sons only and represents the paternal lineage of a male. Females do not have a Y-chromosome and therefore this assay is not applicable. Results are reported as Dog, Coyote, Inconclusive (if found in both dogs and coyotes) or Not Applicable (if female).
- All cases are tested with 28 DNA STR (short tandem repeat) markers that have variants specific to coyotes. Because of their close genetic relationship, coyotes and wolves share many alleles in the markers used for this test but some alleles are found only in coyotes. Coyote-specific alleles in our panel may also be infrequent in coyotes such that not all coyotes possess these alleles. Although our test is powerful enough to detect recent hybridization, absence of coyote-specific alleles is not a guarantee that there is no coyote ancestry.
- All cases have Population Assignment statistical analysis completed with 29 DNA STR markers. Genotype data are compared to a database of medium and large breed dogs, and coyotes from various locations in the United States. Since there are no specific dog breeds associated with coyote-hybrids, dog breeds that are similar in size to coyotes were chosen. Population assignment and admixture analyses determine the likelihood that the subject animal is a dog or a coyote-hybrid.
- (Optional) If required for clarity, a segment of the canine mitochondrial DNA is sequenced and results compared to our database of known coyote and dog mitotypes. Mitochondrial DNA is transmitted by females only and thus represents the maternal lineage of an animal. Results are reported as Dog, Coyote, Inconclusive (if found in both dogs and coyotes) or Not-Applicable (if not completed).
The overall conclusion from multiple assays described above is summarized in the final report as “Dog” or “Coyote-hybrid”.