coyotes in the region were larger than normal coyotes, and they believed that they were a gray wolf and coyote cross. In 1970, the wolf mammalogist L. David Mech proposed that the red wolf was a hybrid of the gray wolf and coyote. However, a 1971 study compared the cerebellum within the brain of six Canis species and found that the cerebellum of the red wolf indicated a distinct species, was closest to that of the gray wolf, but in contrast indicated some characteristics that were more primitive than those found in any of the other Canis species. In 2014, a three-dimensional morphometrics study of Canis species accepted only six red wolf specimens for analysis from those on offer, due to the impact of hybridization on the others. DNA studies Different DNA studies may give conflicting results because of the specimens selected, the technology used, and the assumptions made by the researchers. Phylogenetic trees compiled using different genetic markers have given conflicting results on the relationship between the wolf, dog and coyote. One study based on SNPs (a single mutation), and another based on nuclear gene sequences (taken from the cell nucleus), showed dogs clustering with coyotes and separate from wolves. Another study based on SNPS showed wolves clustering with coyotes and separate from dogs. Other studies based on a number of markers show the more widely accepted result of wolves clustering with dogs separate from coyotes. These results demonstrate that caution is needed when interpreting the results provided by genetic markers. Genetic marker evidence In 1980, a study used gel electrophoresis to look at fragments of DNA taken from dogs, coyotes, and wolves from the red wolf's core range. The study found that a unique allele (expression of a gene) associated with Lactate dehydrogenase could be found in red wolves, but not dogs and coyotes. The study suggests that this allele survives in the red wolf. The study did not compare gray wolves for the existence of this allele. Mitochondrial DNA (mDNA) passes along the maternal line and can date back thousands of years. In 1991, a study of red wolf mDNA indicates that red wolf genotypes match those known to belong to the gray wolf or the coyote. The study concluded that the red wolf is either a wolf × coyote hybrid or a species that has hybridized with the wolf and coyote across its entire range. The