Editing Dog breed (section)

==Genetic evidence==
{{main|Domestication of the dog}}
[[File:The wolf's family portrait.tif|thumb|right|Dogs share a recent common ancestor with modern wolves]]
The domestic dog is the first species, and the only large [[carnivore]], to have been domesticated. The first dogs were certainly wolflike, but the phenotypic changes that coincided with the dog–wolf [[genetic divergence]] are not known.<ref name=freedman2017/> Dogs are the most variable mammal on earth with around 450 globally recognized dog breeds.<ref name=Ostrander2019/> In the [[Victorian era]], directed human [[Selection (biology)|selection]] developed the modern dog breeds, which resulted in a vast range of phenotypes.<ref name=freedman2017/> Most breeds were derived from small numbers of founders within the last 200 years,<ref name=freedman2017/><ref name=Ostrander2019/> and since then dogs have undergone rapid [[Phenotype|phenotypic]] change and were formed into today's modern breeds due to [[artificial selection]] imposed by humans. These breeds can vary in size and weight from a {{convert|0.46|kg|lb|abbr=on}} teacup [[poodle]] to a {{convert|90|kg|lb|abbr=on}} giant [[mastiff]]. The skull, body, and limb proportions vary significantly between breeds, with dogs displaying more phenotypic diversity than can be found within the entire order of carnivores. These breeds possess distinct traits related to morphology, which include body size, skull shape, tail phenotype, fur type and colour.<ref name=freedman2017/> The difference in size has been attributed to a [[long non-coding RNA|lncRNA]] variant in the [[IGF1]] region arisen in wolves from northern latitudes c. 53.000 years ago and fixed by natural and subsequently by human selection.<ref name="IGF1">{{cite journal |first1=Jocelyn|last1=Plassais |date=2022-01-27 |title=Natural and human-driven selection of a single non-coding body size variant in ancient and modern canids |journal=Current Biology |volume=32 |issue=4 |pages=889–897.e9 |doi=10.1016/j.cub.2021.12.036 |pmid=35090588 |pmc=8891063 |bibcode=2022CBio...32E.889P |s2cid=246387681 }}</ref> Their behavioral traits include guarding, herding, and hunting,<ref name=freedman2017/> retrieving, and scent detection. Their personality traits include hypersocial behavior, boldness, and aggression,<ref name=Ostrander2019/> which demonstrates the functional and behavioral diversity of dogs.<ref name=freedman2017/> As a result, today dogs are the most abundant carnivore species and are dispersed around the world.<ref name=Ostrander2019/> The most striking example of this dispersal is that of the numerous modern breeds of European lineage during the [[Victorian era]].<ref name=Frantz2020/>

A genetic study identified 51 regions of the dog [[genome]] which were associated with phenotype variation among breeds in the 57 [[Phenotypic trait|traits]] studied, which included body, cranial, dental, and long bone shape and size. There were three [[Quantitative trait locus|quantitative trait loci]] that explained most of the phenotype variation. Indicators of recent selection were shown by many of the 51 genomic regions that were associated with traits that define a breed, which include body size, coat characteristics, and ear floppiness.<ref name=boyko2010/>

{{cladogram
|caption=[[Cladogram]] of nine breeds that are genetically divergent from others<ref name=parker2004/>|
|cladogram=
{{clade|style=font-size:75%; line-height:75%;width:300px;
  |1=[[Wolf]]
  |2={{clade
       |1={{clade
            |1=[[Shar Pei]]
            |2={{clade
                 |1=[[Shiba Inu]]
                 |2={{clade
                     |1=[[Chow Chow]]
                     |2=[[Akita Inu]]
                   }}
               }}
          }}
       |2={{clade
            |1=[[Basenji]]
            |2={{clade
                |1={{clade
                     |1=[[Siberian Husky]]
                     |2=[[Alaskan Malamute]]
                   }}
                |2={{clade
                     |1={{clade
                          |1=[[Afghan Hound]]
                          |2=[[Saluki]]
                        }}
                     |2=other breeds in the study
                   }}
               }}
          }}
     }}
}}
}}

===Ancient dog breeds===
"Ancient breed" is a term formerly, but no longer used for a particular group of dog breeds by the American Kennel Club.<ref name="American Kennel Club 2006"/><ref>{{cite web|author=American Kennel Club|title=Dog breed groups|url=http://www.akc.org/dog-breeds/groups/}}</ref> These breeds were referred to as "ancient", as opposed to modern, breeds because historically it was believed their origins dated back more than 500 years. 

In 2004, a study looked at the [[Microsatellite#Analysis|microsatellite]]s of 414 purebred dogs representing 85 breeds. The study found that dog breeds were so genetically distinct that 99% of individual dogs could be correctly assigned to their breed based on their [[genotype]], indicating that breeding barriers (purebred breeding) have led to distinct genetic units. The study identified 9 breeds that could be represented on the branches of a [[phylogenetic tree]] which grouped together with strong statistical support and could be separated from the other breeds with a modern European origin. These 9 breeds had been referred to as "ancient breeds". The study found that the [[Pharaoh Hound]] and [[Ibizan Hound]] were not as old as once believed; rather, they had been recreated from combinations of other breeds, and that the [[Norwegian Elkhound]] grouped with the other European dogs despite reports of direct Scandinavian origins dating back 5,000 years.<ref name=parker2004/>

===Dog types===
[[File:Five different types of dogs, woodcut, 1547 Wellcome L0029217.jpg|thumb|"Five different types of dogs", c. 1547.]]

{{further|Dog type}}

[[Dog types]] are broad categories of dogs based on form, function or style of work, lineage, or appearance. In contrast, modern dog breeds are particular breed standards, sharing a common set of heritable characteristics, determined by the kennel club that recognizes the breed. 

The spread of modern dog breeds has been difficult to resolve because many are the product of the controlled breeding practices of the Victorian era (1830–1900).<ref name="Atlas of Dog Breeds of the World"/><ref name="American Kennel Club 2006"/> In 2010, a study looked at 48,000&nbsp;[[SNP genotyping|single nucleotide polymorphism]]s that gave a [[genome]]-wide coverage of 912&nbsp;dogs representing 85&nbsp;breeds.<ref name="vonHoldt_etal_2010">{{cite journal |first1=Bridgett |last1=vonHoldt |date=2010-03-17 |title=Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication |journal=Nature |doi=10.1038/nature08837 |pmid=20237475 |volume=464 |issue=7290 |pages=898–902 |bibcode=2010Natur.464..898V |pmc=3494089 |last2=Lohmueller |first2=Kirk E. |last3=Han |first3=Eunjung |last4=Parker |first4=Heidi G. |last5=Quignon |first5=Pascale |last6=Degenhardt |first6=Jeremiah D. |last7=Boyko |first7=Adam R. |last8=Earl |first8=Dent A. |last9=Auton |first9=Adam |last10=Reynolds |first10=Andy |last11=Bryc |first11=Kasia |last12=Brisbin |first12=Abra |last13=Knowles |first13=James C. |last14=Mosher |first14=Dana S. |last15=Spady |first15=Tyrone C. |last16=Elkahloun |first16=Abdel |last17=Geffen |first17=Eli |last18=Pilot |first18=Malgorzata |last19=Jedrzejewski |first19=Wlodzimierz |last20=Greco |first20=Claudia |last21=Randi |first21=Ettore |last22=Bannasch |first22=Danika |last23=Wilton |first23=Alan |last24=Shearman |first24=Jeremy |last25=Musiani |first25=Marco |last26=Cargill |first26=Michelle |last27=Jones |first27=Paul G. |last28=Qian |first28=Zuwei |last29=Huang |first29=Wei |display-authors=etal}}</ref>

The study found distinct genetic clusters within modern dogs that largely corresponded to [[phenotype]] or function. These included spitz-breeds, toy dogs, spaniels, Mastiff-like breeds, small terriers, retrievers, herding dogs, scent-hounds, and sight-hounds. There were 17&nbsp;breeds that conflicted with phenotype or function and these were thought to be the result of crossing some of the other phenotypes. As in a 2004 study that found 9&nbsp;'ancient breeds' to be genetically divergent, the study found 13&nbsp;breeds that were genetically divergent from the modern breeds: the [[Basenji]], [[Saluki]], [[Afghan hound]], [[Samoyed (dog)|Samoyed]], [[Canaan dog]], [[New Guinea singing dog]], [[dingo]], [[Chow Chow]], [[Chinese Shar Pei]], [[Akita (dog)|Akita]], [[Alaskan malamute]], [[Siberian husky]] and [[American Eskimo dog]].<ref name="vonHoldt_etal_2010" />

The study found that there were three well-supported groups that were highly divergent and distinct from modern domestic dogs. 
*an ''Asian group'' ([[Dingo]], [[New Guinea singing dog]], [[chow chow]], [[Akita (dog)|Akita]] and [[Shar Pei]])
*a ''Middle Eastern'' group ([[Afghan hound]] and [[Saluki]])
*a ''northern group'' ([[Alaskan Malamute]] and [[Siberian Husky]]).<ref name="vonHoldt_etal_2010" />
The earliest books in the English language to mention numbers of dog types are from the "Cynegetica" (hunting literature), namely, ''The Art of Venery'' (1327) by Twiti (Twici), a treatise that describes hunting with the [[limer]] (a leashed [[bloodhound]] type); the pack of ''running hounds'', which included ''barcelets'' and ''brachetz'' (both [[Scent hound|scent hounds]]); and the [[sighthound]] and [[greyhound]].<ref>{{cite book |last=Twiti |first=William |title=The Art of Hunting 1. Stockholm Studies in English XXXVII. |publisher=Almqvist & Wiksell Int. |year=1977 |editor=Danielsson, B. |location=Stockholm |translator=Danielsson, B. |editor2=Cynegetica Anglica |translator2=Cynegetica Anglica}}</ref> More significant in recording the use and description of various dog types is ''[[The Master of Game]]'' (circa 1406) by [[Edward, 2nd Duke of York|Edward of York]],<ref>''The Master of Game'', by Edward, second Duke of York: ed. Baillie-Grohman, William.1st Ed. London: 1904 Ballantine, Hanson & Co Folio, 302pp. 52 pl</ref><ref>{{Cite book |last1=Edward |first1=of Norwich |url=https://archive.org/details/masterofgameo00edwa |title=The master of game : the oldest English book on hunting |last2=Baillie-Grohman |first2=William A. (William Adolph) |last3=Baillie-Grohman |first3=F. (Florence) |last4=Roosevelt |first4=Theodore |last5=Gaston III Phebus |first5=Count of Foix |date=1 January 1909 |publisher=London : Chatto & Windus}}</ref> a treatise that describes dogs and their work, such as the [[alaunt]], greyhound, pack scent hounds, [[spaniel]], and [[mastiff]], used by the privileged and wealthy for hunting purposes. ''The Master of Game'' is a combination of the earlier ''Art of Venery'' and the French hunting treatise ''[[Livre de chasse|Livre de Chasse]]'' by [[Gaston Phoebus]] (circa 1387).<ref>{{Cite web |title=BNF – Le livre de chasse de Gaston Phebus |url=http://classes.bnf.fr/phebus/ |access-date=17 November 2016 |website=classes.bnf.fr}}</ref> ''[[Book of Saint Albans|The Book of Saint Albans]]'', published in 1486,<ref>{{cite book |last=Berners |first=Juliana |title=English hawking and hunting in the Boke of St. Albans : a facsimile edition of sigs. a2-f8 of the Boke of St. Albans (1486) / by Rachel Hands |date=1975 |publisher=Oxford University Press |isbn=0-19-811715-9 |author-link=Juliana Berners |orig-year=Facsimile of 1486 original}}</ref><ref>{{Cite book |last1=Berners |first1=Juliana |url=https://archive.org/details/bokeofsaintalban00bern |title=The boke of Saint Albans |last2=Blades |first2=William |date=1 January 1901 |publisher=London : Elliot Stock}}</ref> a "school" book about [[Hawking (falconry)|hawking]], hunting, fishing, and [[heraldry]], attributed to [[Juliana Berners]] (Barnes), lists dogs of the time mainly by function: "First there is a greyhound, a bastard, a [[mongrel]], a mastiff, a limer, a spaniel, "[[Rache|raches]]" (small-to-medium-sized scenthounds), "kennets" (small hunting dogs), [[Terrier|terriers]], "butcher's hounds", dung-heap dogs, "trundel tails" ([[Lap dog|lapdogs]]?) and prick-eared [[Cur|curs]], and small ladies puppies that bear away the [[Flea|fleas]] and diverse small sorts."

===Basal breeds===
A study in 2012 examined 49,000 [[SNP genotyping|single nucleotide polymorphism]]s that gave a [[genome]]-wide coverage of 1,375 dogs representing 35 breeds, 19 wolves, and previous published genetic signatures of other breeds, giving a total of 121 breeds covered. The study found a deep genetic split between old-world and new-world wolves, and confirmed the genetic divergence of 13 breeds from a 2010 study ([[Afghan Hound]], [[Akita (dog)|Akita]], [[Alaskan Malamute]], [[American Eskimo]], [[Basenji]], [[Canaan dog]], [[Chow Chow]], [[Dingo]], [[New Guinea singing dog]], [[Saluki]], [[Samoyed (dog)|Samoyed]], [[Shar-Pei]], [[Siberian Husky]]), plus another three: the [[Eurasier]], [[Finnish Spitz]] and [[Shiba Inu]]. The study referred to these 16 as [[Basal (phylogenetics)|basal]] breeds, as opposed to ancient breeds, as they exhibited genetic divergence but not all of them were historically considered to be "ancient breeds".<ref name=larson2012/>
[[image:Phylogenetic tree of ancient dog breeds.png|right|400px|thumb|Phylogenetic tree of ancient dog breeds]]
The 2012 study found that modern breeds only emerged in the 19th century and that claims of their antiquity are based on little or no historical or empirical evidence. The study indicated that throughout history, global dog populations experienced numerous episodes of diversification and homogenization, with each round further reducing the power of genetic data derived from modern breeds to help infer their early history.<ref name=larson2012/>

Of the basal breeds, the [[American Eskimo Dog]] and [[Eurasier]] were the very recent product of cross-breeding other basal breeds. Most basal breeds have hybridized with other lineages in the past. If those other lineages were other basal breeds then a basal genetic signature remains. The combination of introgression and past population bottlenecks suggested that basal breeds have little or no genetic connections to their ancestral populations and that their genetic distinctiveness does not signify ancient heritage. They are distinctive from the modern breeds because the genetic heritage of the modern breeds has become blurred due to admixture, and the basal breeds have mostly avoided admixture with them due to geographic or cultural barriers.<ref name=larson2012/>

===Medical research===
As dogs are a subspecies but their breeds are distinct genetic units, and because only certain breeds share the same type of cancers as humans, the differences in the genes of different breeds may be useful in human medical research.<ref>{{cite journal | last1 = Cadieu | first1 = Edouard | last2 = Ostrander | first2 = Elaine A. | year = 2007| title = Canine Genetics Offers New Mechanisms for the Study of Human Cancer | url = http://cebp.aacrjournals.org/cgi/content/full/16/11/2181 | journal = Cancer Epidemiology, Biomarkers & Prevention | volume = 16 | issue = 11| pages = 2181–2183 | doi = 10.1158/1055-9965.EPI-07-2667 | pmid = 17982116 | doi-access =  | s2cid = 28325634 }}</ref>

===Breed temperament===
In 2014, a study indicated that some breed-temperaments, such as anxiety or fear, may be linked to gene mutations. Other temperaments may be due to the legacies of 'ancient' ancestry.<ref>{{cite book |doi=10.1007/978-3-642-53994-7_2 |chapter=Dog Breeds and Their Behavior |title=Domestic Dog Cognition and Behavior |pages=31–57 |year=2014 |last1=Serpell |first1=James A. |last2=Duffy |first2=Deborah L. |isbn=978-3-642-53993-0|s2cid=81062726 }}</ref>