Editing Eastern wolf (section)

==Taxonomy==
[[File:Washtenaw County's last wolf (1907).jpg|thumb|Taxidermy exhibit of an eastern wolf killed on February 10, 1907, in [[Washtenaw County, Michigan]]]]

The first published name of a taxon belonging to the genus ''Canis'' from North America is ''Canis lycaon''. It was published in 1775 by the German naturalist [[Johann Christian Daniel von Schreber|Johann Schreber]], who had based it on the earlier description and illustration of one specimen that was thought to have been captured near Quebec. It was later reclassified as a subspecies of gray wolf by [[Edward Alphonso Goldman|Edward Goldman]].<ref name=chambers2012/>

In the third edition of ''[[Mammal Species of the World]]'' published in 2005, the mammalogist [[:de:W. Christopher Wozencraft|W. Christopher Wozencraft]] listed the eastern wolf as a gray wolf subspecies,<ref name=msw3/> which supports its earlier classification based on morphology in three studies.<ref name=goldman1937/><ref name=goldman1944/><ref name=nowak2002/> This taxonomic classification has since been debated.

In 2021, the [[American Society of Mammalogists]] considered the eastern wolf as its own species (''Canis lycaon'').<ref name=MDD/>

===Taxonomic debate===
When European settlers first arrived to North America, the [[coyote]]'s range was limited to the western half of the continent. They existed in the arid areas and across the open plains, including the prairie regions of the midwestern states. Early explorers found some in Indiana and Wisconsin. From the mid-1800s coyotes began expanding beyond their original range.<ref name=nowak1979/>

The taxonomic debate regarding North American wolves can be summarised as follows:
{{blockquote|There are two prevailing evolutionary models for North American ''Canis'':
;(i)&nbsp;a&nbsp;two-species model: that identifies grey wolves (''C.&nbsp;lupus'') and (western) coyotes (''Canis latrans'') as distinct species that gave rise to various hybrids, including the Great Lakes-boreal wolf (also known as Great Lakes wolf), the eastern coyote (also known as coywolf / brush wolf / tweed wolf), the red wolf and the eastern wolf;

or

;(ii)&nbsp;a&nbsp;three-species model: that identifies the grey wolf, western coyote, and eastern wolf (''C.&nbsp;lycaon'') as distinct species, where Great Lakes-boreal wolves are the product of grey wolf × eastern wolf hybridization, eastern coyotes are the result of eastern wolf × western coyote hybridization, and red wolves are considered historically the same species as the eastern wolf, although their contemporary genetic signature has diverged owing to a bottleneck associated with captive breeding.<ref name=rutledge2015/>}}

The evolutionary biologist Robert K. Wayne, whose team is involved in an ongoing scientific debate with the team led by Linda K. Rutledge, describes the difference between these two evolutionary models: "In a way, it is all semantics. They call it a species, we call it an ecotype."<ref name=beeland2013/>

====Paleontological evidence====
Some of the earliest ''Canis'' specimens were discovered at Cripple Creek Sump, [[Fairbanks]], Alaska, in strata dated 810,000&nbsp;years old. The dental measurements of the specimens clearly match historical ''Canis lycaon'' specimens from Minnesota.<ref name=tedford2009/>

====Genetic evidence====
[[Mitochondrial DNA]] (mDNA) passes along the maternal line and can date back thousands of years.<ref name=beeland2013/>

In 1991, a study of the [[mitochondrial DNA]] (mDNA) sequences of wolves and coyotes from across North America found that the wolves of the Minnesota, Ontario and Quebec regions possessed coyote [[genotypes]]. The study proposes that dispersing male gray wolves were mating with coyote females in deforested areas bordering wolf territory. The distribution of coyote genotypes within wolves matched the phenotypic differences between these wolves found in an earlier study, with the larger Great Lakes wolf found in Minnesota, the smaller Algonquin ([[Algonquin Provincial Park|Provincial Park]]) type found in central Ontario, and the smallest and more coyote-like [[Eastern coyote|tweed wolf or eastern coyote]] type occupying sections of southeastern Ontario and southern Quebec.<ref name=lehman1991/>

{{cladogram
|title=Proposed phylogenetic tree of wolf evolution
|cladogram=
  {{clade
  |label1 = Ancestral Canid{{br}}(1-2 million years ago)
  |1 =
    {{clade
    |1 =
      {{clade
      |1 = [[Coyote]]
      |2 =
        {{clade
        |1 = [[Red wolf]]
        |2 = Eastern wolf
        }}
      }}
    |label2 = [[Gray wolf]]
    |grouplabel2 = [[Subspecies of Canis lupus|Gray wolf subspecies]]
    |bar2 = grey
    |2 =
      {{clade
      |1 = {{clade}}
      |2 = {{clade}}
      }}
    }}
  }}
}}

In 2000, a study looked at red wolves and eastern wolves from both eastern Canada and Minnesota. The study agreed that these two wolves readily hybridize with the coyote. The study used 8&nbsp;[[microsatellites]] (genetic markers taken from across the [[genome]] of a specimen). The phylogenetic tree produced from the genetic sequences showed a close relationship among the red wolves and the eastern wolves from Algonquin Park, southern Quebec, and Minnesota such that they all clustered 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&nbsp;years ago. No gray wolf sequences were detected in the samples. The study proposed that these findings are inconsistent with the two wolves being subspecies of the gray wolf, that red wolves and eastern wolves (eastern Canadian and Minnesota) evolved in North America after having diverged from the coyote, and therefore they are more likely to hybridize with coyotes.<ref name=wilson2000/>

In 2009, a study of eastern Canadian wolves – which was referred to as the "Great Lakes" wolf in this study – 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.<ref name=koblmuller2009/> This study was quickly rebutted on the grounds that it had misinterpreted the findings of earlier studies that it relied upon, nor did it provide a definition for a number of the terms that it used, such as "ecotype".<ref name=cronin2009/>

In 2011, a study compared the genetic sequences of 48,000&nbsp;[[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&nbsp;years ago. The eastern wolf – which was referred to as the "Great Lakes" wolf in this study – was 58% gray wolf and 42% coyote with hybridization having occurred 546–963&nbsp;years ago. The study rejected the theory of a common ancestry for the red and eastern wolves.<ref name=vonholdt2011/><ref name=beeland2013/> 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 eastern wolf is not a hybrid but a separate species.<ref name=rutledge2012a/><ref name=beeland2013/> The 2012 study proposed that there are three true canis species in North America – the gray wolf, the western coyote, and red wolf/eastern wolf with the eastern wolf represented by the Algonquin wolf, with the Great Lakes wolf being a hydrid of the eastern wolf and the gray wolf, and the eastern coyote being a hybrid of the western coyote and the eastern (Algonquin) wolf.<ref name=rutledge2012a/>

Also in 2011, a scientific [[literature review]] was undertaken to help assess the taxonomy of North American wolves. One of the findings proposed was that the eastern wolf, whose range includes eastern Canada and the Upper Peninsula of Michigan plus Wisconsin and Minnesota is supported as a separate species by morphological and genetic data. Genetic data supports a close relationship between the eastern and red wolves, but not close enough to support these as one species. It was "likely" that these were the separate descendants of a common ancestor shared with coyotes. This review was published in 2012.<ref name=chambers2012/>

Another study of both mDNA and yDNA in wolves and coyotes by the same authors indicates that the eastern wolf is genetically divergent from the gray wolf and is a North American evolved species with a long-standing history. The study could not dismiss the possibility of the eastern wolf having evolved from an ancient hybridization of gray wolf and coyote in the Late Pleistocene or Early Holocene.<ref name=wilson2012/> Another study by the same authors found that eastern wolf mDNA genetic diversity had been lost after their culling in the early 1960s, leading to the invasion of coyotes into their territory and introgression of coyote mDNA.<ref name=rutledge2012b/>

In 2014, the [[National Center for Ecological Analysis and Synthesis]] was invited by the [[United States Fish and Wildlife Service]] to provide an independent review of its proposed rule relating to gray wolves. The Center's panel findings were that the proposed rule was heavily dependent upon the analysis contained in a scientific literature review conducted in 2011 (Chambers et al.), that this work was not universally accepted and that the issue was "not settled", and that the rule does not represent the "best available science".<ref name=dumbacher2014/> Also in 2014, an experiment to hybridize a captive western gray wolf and a captive western coyote was successful, and therefore possible. The study did not assess the likelihood of such hybridization in the wild.<ref name=mech2014/>

In 2015, the [[Committee on the Status of Endangered Wildlife in Canada]] changed its designation of the eastern wolf from ''Canis lupus lycaon'' to ''Canis cf. lycaon'' (''Canis'' species believed to be ''lycaon'')<ref name=COSEWIC2015/> and a species at risk.<ref name=SRPR2015/>

Later that year, a study compared the [[DNA sequences]] using 127,000&nbsp;single-nucleotide polymorphisms (mutations) of wolves and coyotes, but did not include red wolves and used Algonquin wolves as the representative eastern wolf, not wolves from the western Great Lakes states (usually referred to as Great Lakes wolves). The study indicated that Algonquin wolves were a distinct genomic cluster, even distinct from the Great Lakes states' wolves, which it found were actually hybrids of the gray wolf and the Algonquin wolf.  The study's results did not exclude a possibility that the Great Lakes states' wolf (the gray wolf x eastern wolf hybrid (''C.&nbsp;l.&nbsp;lycaon'')) historically inhabited southern Ontario, southern Quebec and the northeastern United States alongside the Algonquin wolf, as there is evidence to suggest both inhabited those areas.<ref name=rutledge2015/>

In 2016, a study of mDNA once again indicated the Eastern wolf as a coyote–wolf hybrid.<ref name=ersmark2016/>

In 2018, a study looked at the [[Y-chromosome]] male lineage of canines. The unexpected finding was that the one Great Lakes wolf specimen included in this study showed a high degree of [[genetic divergence]]. Previous studies propose the Great Lakes wolf to be an ancient ecotype of the gray wolf that had experienced genetic [[introgression]] from other types of gray wolves and coyotes. The study called for further research into the Y-chromosomes of coyotes and wolves to ascertain if this is where this unique genetic male lineage may have originated from.<ref name=oetjens2018/>

====Genomic evidence====
In 2016, a [[Whole genome sequencing|whole-genome]] DNA study proposed, based on the assumptions made, that all of the North American wolves and coyotes diverged from a common ancestor less than 6,000–117,000&nbsp;years ago, including the coyote diverging from Eurasian wolf about 51,000&nbsp;years ago (which matches other studies indicating that the extant wolf came into being around this time), the red wolf diverging from the coyote between 55,000–117,000&nbsp;years ago, and the eastern wolf (Great Lakes region and Algonquin) wolf diverging from the coyote 27,000–32,000&nbsp;years ago, and asserts that these do not qualify as an ancient divergences that justify them being considered unique species.<ref name=vonholdt2016/>

The study also indicated that all North America wolves have a significant amount of coyote ancestry and all coyotes some degree of wolf ancestry, and that the [[red wolf]] and eastern wolf are highly [[Genetic admixture|admixed]] with different proportions of gray wolf and coyote ancestry. The study found that coyote ancestry was highest in red wolves from the southeast of the United States and lowest among the Great Lakes wolves.<ref name=vonholdt2016/>

The study also determined how unique each type of canids alleles were compared to Eurasian wolves, all of which had no coyote ancestry. It found the following proportion of unique alleles: coyotes 5.13% unique; red wolf 4.41%; Algonquin wolves 3.82%; Great Lakes wolves 3.61%; and gray wolves 3.3%. They asserted that the amount of unique alleles in all wolves was lower than expected and does not support an ancient (greater than 250,000&nbsp;years) unique ancestry for any of the species.<ref name=vonholdt2016/>

The authors contended that the proportion of unique alleles and ratio of wolf / coyote ancestry findings matched the south to north disappearance of the wolf due to European colonization since the 18th&nbsp;century and the resulting loss of habitat. Bounties led to the extirpation of wolves initially in the southeast, and as the wolf population declined wolf–coyote admixture increased. Later, this process occurred in the Great Lakes region and then eastern Canada with the influx of coyotes replacing wolves, followed by the expansion of coyotes and their hybrids. The Great Lakes and Algonquin wolves largely reflect lineages that have descendants in the modern wolf and coyote populations, but also reflect a distinct gray wolf ecotype which may have descendants in the modern wolf populations.<ref name=vonholdt2016/>

As a result of these findings, the [[American Society of Mammalogists]] recognizes ''Canis lycaon'' as its own species.<ref name=MDD/>

The proposed timing of the wolf/coyote divergence conflicts with the finding of a coyote-like specimen in strata dated to 1&nbsp;million years before present.<ref name=wang2008/>

In 2017 a group of canid researchers challenged the 2016 whole-genome DNA study's finding that the red wolf and the eastern wolf were the result of recent coyote–gray wolf hybridization. The group asserts the three-year [[generation time]] used to calculate the divergence periods between different species was lower than empirical estimates of 4.7&nbsp;years. The group also found deficiencies in the previous study's selection of specimens (two representative coyotes were from areas where recent coyote and gray wolf mixing with eastern wolves is known to have occurred), the lack of certainty in the ancestry of the selected Algonquin wolves, and the grouping of Great Lakes and Algonquin wolves together as eastern wolves, despite opposing genetic evidence.  As well, they asserted the 2016 study ignored the fact that there is no evidence of hybridization between coyotes and gray wolves.<ref name=hohenlohe2017/>

The group also questioned the conclusions of genetic differentiation analysis in the study stating that results showing Great Lakes, Algonquin and red wolves, plus eastern coyotes differentiated from gray and Eurasian wolves were actually more consistent with an ancient hybridization or a distinct cladogenic origin for the red and Algonquin wolves than of a recent hybrid origin. The group further asserted that the levels of unique alleles for red and Algonquin wolves found the 2017 study were high enough to reveal a high degree of evolutionary distinctness. Therefore, the group argues that both the red wolf and the eastern wolf remain genetically distinct North American taxa.<ref name=hohenlohe2017/> This was rebutted by the authors of the earlier study.<ref name=vonholdt2017/>

====Wolf genome====
Genetic studies relating to wolves or dogs have inferred phylogenetic relationships based on the only reference genome available: that of the dog breed called the Boxer. In 2017, the first reference genome of the wolf ''Canis lupus lupus'' was mapped to aid future research.<ref name=gopalakrishnan2017/> In 2018, a study looked at the genomic structure and admixture of North American wolves, wolf-like canids, and coyotes using specimens from across their entire range that mapped the largest dataset of nuclear genome sequences and compared these against the wolf reference genome. The study supports the findings of previous studies that North American gray wolves and wolf-like canids were the result of complex gray wolf and coyote mixing. A polar wolf from Greenland and a coyote from Mexico represented the purest specimens. The coyotes from Alaska, California, Alabama, and Quebec show almost no wolf ancestry. Coyotes from Missouri, Illinois, and Florida exhibit 5–10% wolf ancestry. There was 40%:60% wolf to coyote ancestry in red wolves, 60%:40% in eastern wolves, and 75%:25% in the Great Lakes wolves. There was 10% coyote ancestry in Mexican wolves, 5% in Pacific Coast and Yellowstone wolves, and less than 3% in Canadian archipelago wolves.<ref name=sinding2018/>

The study indicates that the genomic ancestry of red, eastern and Great Lakes wolves were the result of admixture between modern gray wolves and modern coyotes. This was then followed by development into local populations. Individuals within each group showed consistent levels of coyote to wolf inheritance, indicating that this was the result of relatively ancient admixture. The eastern wolf as found in Algonquin Provincial Park is genetically closely related to the Great Lakes wolf as found in Minnesota and Isle Royale National Park in Michigan. If a third canid had been involved in the admixture of the North American wolf-like canids, then its genetic signature would have been found in coyotes and wolves, which it has not.<ref name=sinding2018/>

Later in 2018, a study based on a much smaller sample of 65,000&nbsp;SNPs found that although the eastern wolf carries regional gray wolf and coyote [[alleles]] (gene variants), it also exhibits some alleles that are unique and therefore worthy of conservation.<ref name=heppenheimer2018/>

In 2023, a genomic study indicates that eastern wolves have evolved separately from grey wolves for the past 67,000 years and had experienced admixture with coyotes 37,000 years ago. The Great Lakes wolves were the result of admixture between eastern wolves and grey wolves 8,000 years ago. Eastern coyotes were the result of admixture between eastern wolves and "western" coyotes during the last century.<ref>{{cite journal|title=Tracing Eastern Wolf Origins From Whole-Genome Data in Context of Extensive Hybridization|journal=Molecular Biology and Evolution|doi=10.1093/molbev/msad055|year=2023|author=Vilaca S.T.|volume=40 |issue=4 |pages=msad055 |pmid=37046402 |pmc=10098045}}</ref>

====Ancestor====
The software that is currently used to conduct whole genome analysis for evidence of hybridization does not distinguish between past and present hybridization. In 2021, an mDNA analysis of modern and extinct North American wolf-like canines indicates that the extinct Late Pleistocene [[Beringian wolf#Range|Beringian wolf]] was the ancestor of the southern wolf [[Clade#Definition|clade]], which includes the [[Mexican wolf]] and the [[Great Plains wolf]]. The Mexican wolf is the most ancestral of the gray wolves that live in North America today. The modern coyote appeared around 10,000 years ago. The most genetically basal coyote mDNA clade pre-dates the [[Last Glacial Maximum]] and is a haplotype that can only be found in the Eastern wolf. This implies that the large, wolf-like [[Pleistocene coyote]] was the ancestor of the Eastern wolf. Further, another ancient haplotype detected in the Eastern wolf can be found only in the Mexican wolf. The authors propose that Pleistocene coyote and Beringian wolf admixture led to the Eastern wolf long before the arrival of the modern coyote and the modern wolf.<ref name=Wilson2021/>