When and where your dog evolved from the wolf - 5
Where did the domestic dog come from? There have been many articles written on the subject which usually cite hearsay or old science theories. The difficulty has always been in the structure of the scientific experiments, DNA sampling and having a sufficient sample of domestic dogs diverse in breed and geographic location.
For those who like a spoiler, the latest research in a 2009 scientific paper suggests that : “results indicate that the domestic dog originated in southern China less than 16,300 years ago, from several hundred wolves.” Ref 1
While this may not seem surprising, the thoroughness of the research, and the scientific theory used makes this study and conclusion by far the most precise yet. For those interested in how the researchers drew these conclusions, the following is a brief summary of the paper submitted to the Oxford journal.
The authors reviewed previous studies but concluded that the use of mitochondrial DNA (mtDNA) failed to provide an accurate time or origin of the domestic dog species because of lack of phylogenetic resolution (study of evolutionary relatedness among various groups of organisms) and poor sampling.
What these scientists did differently was that they analysed the entire mitochondrial genomes for 169 dogs to (for maximum phylogenetic resolution) and compared this to control group of 1,543 dogs across the ‘Old World’ (see map). This research has for the first time provided a detailed map of the origins of the domestic dog in space and time, the number of founders and the likely human interaction that caused all of this to happen.
A core part of the theory is based on the discovery that ALL dogs share a common homogenous gene pool containing 10 major haplogroups. “However, the full range of genetic diversity, all 10 haplogroups, was found only in south eastern Asia south of Yangtze River, and diversity decreased following a gradient across Eurasia, through seven haplogroups in Central China and ?ve in North China and Southwest (SW) Asia, down to only four haplogroups in Europe. The mean sequence distance to ancestral haplotypes indicates an origin 5,400–16,300 years ago (ya) from at least 51 female wolf founders. These results indicate that the domestic dog originated in southern China less than 16,300 years ago, from several hundred wolves.” Ref 1
The time and location corresponds to sedentary rice farmers in the region who most likely began the practice of taming wolves for their protection which caught on as an accepted cultural norm.
I personally find the recency of the creation of the domestic dog and the precision of its location to be an amazing scientific breakthrough. When one considers that modern man has been around several orders of magnitude longer than domestic dogs, and the diversity that dog breeds have reached through targeted man made breeding, 15,000 years is a very short time.
Genetic diversity in southern Eastern Asia.
The Old world map below shows how geographically diverse the samples used in this study were. The SE Asia map on the right shows the dog sample regions in yellow that are very close to the origin of the domestic dog species. The map text boxes provide information about proximity to the origin centre. One of the most relevant subgroups of data is the SC values. SC represents the 6 non-universal (of the total 10) subclades of clades A, B, and C. Thus the closer the number of SC elements are to six, the more likely a region is the origin of the birth of the domestic dog.
Where did wolves come from?
With the above evidence for the time and location of the creation of the domestic dogs, aren’t you a little curious about where the dogs ancestor, the wolf, came from?
Historically archaeological evidence and human records have suggested that wolves were distributed throughout most of Eurasia and North America (Gao 1997, 2006; Nowak 2003).
Similar to the development of the domestic dog, the evolution of the wolf is somewhat clouded. One reference believes that wolves evolved from “a primitive carnivores known as miacids. The miacids ranged from gopher-sized to dog-sized animals, and appeared in the Lower Tertiary about fifty two million years ago. Miacids in turn had evolved from Cretaceous insectivores. The direct descendants of miacids today are animals called viverrids, which include the genet of Africa.” Ref 2
Depiction of the Miacid wolf ancestor (Ref 3)
Evolution theory suggests that from the miacids evolved three canids. The the first canid (Cynodictis) was called the dawn-wolf. This animal looked like an elongated fox and could climb and live in trees.
Robert Wayne (University of California) theorized that several wolf-like canids diverged from a common ancestor about 2-3 million years ago. The first grey wolf, (Canis Lupis), appeared in Eurasia around one million years ago then migrated to North America 750,000 years ago.
The Dire Wolf, (Canis Dirus) was larger and heavier than the grey wolf of the time and more like a hyena, but they co existed around 400,000 years.
The third canid is the coyote. It is interesting that of the three canids, only the wolf (grey and red) and the coyote survived an event that caused many mammals to become extinct 10,000 years ago.
Evolution tree for wolves/ dogs (ref 4)
Ref 1 mtDNA Data Indicate a Single Origin for Dogs South of Yangtze River, Less Than 16,300 Years Ago, from Numerous Wolves. Authors: Jun-Feng Pang, Cornelya Kluetsch, Xiao-Ju Zou et al,
Ref 2 http://www.wolfcountry.net/information/WolfOrigins.html
Ref 3 myacad image theroamingnaturalist.wordpress.com
Ref 4 wolf evolution tree - retrieverman.wordpress.com
Article by Bruce Dwyer. If you wish to use any of this information please refer to the article as a reference and provide a link to http://www.dogwalkersmelbourne.com.au