Deciphering dog domestication through a combined ancient DNA and geometric morphometric approach

Lead Research Organisation: University of Liverpool
Department Name: Archaeology Classics and Egyptology

Abstract

The shift from hunting and gathering to an agricultural way of life was one of the most profound events in the history of our species and one which continues to impact our existence today. Understanding this process is key to understanding the origins and rise of human civilization. Despite decades of study, however, fundamental questions regarding why, where and how it occurred remain largely unanswered.

Such a fundamental change in human existence could not have been possible without the domestication of selected animals and plants. The dog is crucial in this story since it was not only the first ever domestic animal, but also the only animal to be domesticated by hunter-gatherers several thousand years before the appearance of farmers.

The bones and teeth of early domestic dogs and their wild wolf ancestors hold important clues to our understanding of how, where and when humans and wild animals began the relationship we still depend upon today. These remains have been recovered from as early as 15,000 years ago in numerous archaeological sites across Eurasia suggesting that dogs were either domesticated independently on several occasions across the Old World, or that dogs were domesticated just once and subsequently spreading with late Stone Age hunter gatherers across the Eurasian continent and into North America. There are also those who suggest that wolves were involved in an earlier, failed domestication experiment by Ice Age Palaeolithic hunters about 32,000 years ago. Despite the fact that we generally know the timing and locations of the domestication of all the other farmyard animals, we still know very little for certain about the origins of our most iconic domestic animal.

New scientific techniques that include the combination of genetics and statistical analyses of the shapes of ancient bones and teeth are beginning to provide unique insights into the biology of the domestication process itself, as well as new ways of tracking the spread of humans and their domestic animals around the globe. By employing these techniques we will be able to observe the variation that existed in early wolf populations at different levels of biological organization, identify diagnostic signatures that pinpoint which ancestral wolf populations were involved in early dog domestication, reveal the shape (and possibly the genetic) signatures specifically linked to the domestication process and track those signatures through time and space.

We have used this combined approach successfully in our previous research enabling us to definitively unravel the complex story of pig domestication in both Europe and the Far East. We have shown that pigs were domesticated multiple times and in multiple places across Eurasia, and the fine-scale resolution of the data we have generated has also allowed us to reveal the migration routes pigs took with early farmers across Europe and into the Pacific. By applying this successful research model to ancient dogs and wolves, we will gain much deeper insight into the fundamental questions that still surround the story of dog domestication.

Planned Impact

As "man's best friend", the dog is the most iconic domestic animal. There are currently more than 400 million dogs worldwide, 72 million living in households in the USA, and a further 10.5 million in the UK. A huge and diverse industry exists that caters to both dogs and (more importantly) their owners, with households in the US alone estimated to spend $4.1bn on their pets by the end of 2012, the vast majority of which is dedicated to dogs.

The principal beneficiaries of our research will be the general public who have a broad appetite and interest in archaeology and natural history, as evidenced by the number and popularity of TV programs dedicated to these topics. We have shown through our pig domestication research that there is broad public appeal for stories about animal domestication, and the iconic status of dogs in human society will only reinforce this. We have a great deal of experience with the media, having taken part in a range of TV and Radio broadcasts featuring our domestication research including BBC1 and 2, Radio 4, German ZDF, National Geographic and the Discovery Channel. We will therefore carefully plan and coordinate active participation in relevant media opportunities.

Beyond this are a wide range of specific user groups directly or indirectly linked to the diverse industries and specialist interest groups associated with dogs as pets. In this respect we have identified the relevant Kennel Clubs (principally in the UK and US), who promote the concept of recognised dog breeds with documented bloodlines and defined phenotypic characteristics, as well as various specialist commercial genetic testing labs for dogs who offer definitive information regarding the genetic history and breed make-up of pet dogs. The imposition of rigorous breed definitions by these groups has resulted in the proliferation and widespread acceptance of a range of pathological phenotypes in modern pedigree dog breed definitions, many of which compromise the health of the dog. This phenomenon led to a Panorama investigation resulting in the subsequent controversial decision by the BBC to withdraw its TV coverage of Crufts Dog Show in 2008. Addressing this growing ethical problem has led to the UK Kennel Club's instigation of veterinary checks as part of the dog judging process at competitions; a decision that has led to protests by breeders. Our data will likely challenge long-held assumptions about the antiquity and validity of dog variation and specific breed definition, and will likely be used by media organisations and other interest groups alike to inform a variety of decision making processes. We will engage with all these groups in a positive dialogue to explore ways of presenting a balanced debate in the way our results may be used.

The vast number of dog interest magazines means that the inevitable narratives we will uncover regarding dog domestication will ensure worldwide coverage by additional users groups. In this respect we will directly engage with the most popular listed dog magazines (i.e. Bark, Dog Fancy, Dog World, Dog's Life, Fido Friendly, Family Dog and Hollywood Dog) alerting them to new findings and popular stories from our project. Unravelling the origins of man's best friend will undoubtedly generate huge public interest and we will inform dog owners about the myths and misinformation about dog origins.

Beyond that, there are major additional opportunities to impact numerous additional user-groups and beneficiaries in the form of internet sites and publication vehicles for specific dog breed groups, veterinary organisations and charities (e.g. the Dogs Trust), major retail outlets, as well as welfare and rescue organisations (e.g. RSPCA). With such a diverse network of potential interested parties, user groups and beneficiaries, the impact trajectory of our research findings are likely to be regular, sustained and on a global scale.

Publications

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Ameen C (2019) Specialized sledge dogs accompanied Inuit dispersal across the North American Arctic in Proceedings of the Royal Society B: Biological Sciences

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Bergström A (2020) Origins and genetic legacy of prehistoric dogs. in Science (New York, N.Y.)

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MacHugh DE (2017) Taming the Past: Ancient DNA and the Study of Animal Domestication. in Annual review of animal biosciences

 
Description We have generated an unprecedented dataset of DNA and morphological assessment of >3000 canid samples from across the world and spanning the last 30,000 years. Thus far we have published several key papers using both datasets. The first morphological publication demonstrated that tooth crowding, a common measure for distinguishing dogs from wolves, is highly variable and many more wolves possess this trait than thought, thus undermining the use of this trait as a proxy for domestication. The first major publication stemming from the ancient DNA approach was published in 2016 and suggested on the basis of the first ancient dog genome and a comprehensive look at the archaeological record that dogs may have been domesticated from independent wolf populations on both sides of the Old World. A second published in Science revealed no evidence for early American dogs having been domesticated from indigenous wolf populations. Instead several introductions of domestic dogs took place during the Holocene, with the earliest palaeoindian dogs being wholly replaced by later arctic and european dogs. A fascinating modern legacy of the palaeoindian dogs remains in modern domestic dogs as a sexually transmitted cancer. An methodological paper using modern comparative wolf and dog data showed that a commonly cited 'signal' of domestication - tooth crowding - is not a definitive sign of the domestication process (at least in wolves). A recent paper (2019) published in Proceedings of the Royal Society B. reveals the genetic and morphological history of the arctic sled dog introductions to the Americas. Others also published in 2019 include: 1) evidence that modern wolves trace their ancestry to a late Pleistocene expansion from Beringia (Molecular Biology); 2) findings of large genetic influences on modern dog ownership has implications for understanding domestication and health associations (Nature scientific Reports) and 3) that Dire wolves were the last of an ancient New World canid lineage (in review Nature). More data from the project continues to be analysed with further analyses and publications in the pipeline. The huge dataset of morphometric data are aslo finally being compiled and analysed through our ongoing collaborators.
Exploitation Route Our group has developed a successful research model that combines genetic and novel morphometric approaches with direct dating. We were the first to do this successfully and it is now a model for similar projects run by colleagues around the world.
Sectors Agriculture, Food and Drink,Education,Culture, Heritage, Museums and Collections,Other

URL http://domestication.org.uk/
 
Description The research described has through TV and radio programmes, raising public awareness and understanding of the history of domestic animals. impacts through film and book sales.
First Year Of Impact 2013
Sector Agriculture, Food and Drink,Education,Culture, Heritage, Museums and Collections,Other
Impact Types Cultural,Societal

 
Description Standard Grant
Amount £880,000 (GBP)
Funding ID AH/N004558/1 
Organisation Arts & Humanities Research Council (AHRC) 
Sector Public
Country United Kingdom
Start 04/2017 
End 04/2020
 
Description Being Human 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Over 1,000 people attended a multi-hour and multi-activity event at the Natural History Museum in Oxford associated with the Being Human event.
Year(s) Of Engagement Activity 2016