study proposed that the red wolf is a southeastern occurring subspecies of the gray wolf that has undergone hybridization due to an expanding coyote population; however, being unique and threatened that it should remain protected. This conclusion led to debate for the remainder of the decade. In 2000, a study looked at red wolves and eastern Canadian wolves. The study agreed that these two wolves readily hybridize with the coyote. The study used eight microsatellites (genetic markers taken from across the genome of a specimen). The phylogenetic tree produced from the genetic sequences showed red wolves and eastern Canadian wolves clustering together. These then clustered next closer with the coyote and away from the gray wolf. A further analysis using mDNA sequences indicated the presence of coyote in both of these two wolves, and that these two wolves had diverged from the coyote 150,000–300,000 years ago. No gray wolf sequences were detected in the samples. The study proposes that these findings are inconsistent with the two wolves being subspecies of the gray wolf, that red wolves and eastern Canadian wolves evolved in North America after having diverged from the coyote, and therefore they are more likely to hybridize with coyotes. In 2009, a study of eastern Canadian wolves using microsatellites, mDNA, and the paternally-inherited yDNA markers found that the eastern Canadian wolf was a unique ecotype of the gray wolf that had undergone recent hybridization with other gray wolves and coyotes. It could find no evidence to support the findings of the earlier 2000 study regarding the eastern Canadian wolf. The study did not include the red wolf. In 2011, a study compared the genetic sequences of 48,000 single nucleotide polymorphisms (mutations) taken from the genomes of canids from around the world. The comparison indicated that the red wolf was about 76% coyote and 24% gray wolf with hybridization having occurred 287–430 years ago. The eastern wolf was 58% gray wolf and 42% coyote with hybridization having occurred 546–963 years ago. The study rejected the theory of a common ancestry for the red and eastern wolves. However the next year, a study reviewed a subset of the 2011 study's Single-nucleotide polymorphism (SNP) data and proposed that its methodology had skewed the results and that the red and eastern wolves are not hybrids but are in fact the same species separate from the gray wolf. The 2012 study proposed that there