by Alessia Colaianni
The genomes of 2,155 specimens studied from different breeds are linked to over 18,000 questionnaires on physical and behavioral traits collected on the Darwin’sArk platform: genetics appear to play a role in only 9% of cases (and not exclusively).
The friendly, intelligent and devoted Golden Retriever; the loving, loyal and courageous Bullmastiff. Flipping through the American Kennel Club’s dog breed factsheets, you’ll find three adjectives that define their outstanding traits. But will breed really show us how a dog behaves? There are those who do not adopt from kennels and buy puppies from kennels hoping to find the dog that best suits their needs based on breed. Even at the legal level, some local ordinances (though no longer national) designate some breeds as dangerous, to the point of outlawing breeding or keeping them in some states, while insurance companies are considering higher premiums from breed owners who are aggressive. Research soon to be published in Science seems to change the tables: genome analysis of numerous dogs suggests breed and behavior are not so closely linked.
We know well that the evolutionary history of the dog has distant origins and that Homo sapiens have been choosing dogs, intentionally or not, for thousands of years. Some archaeological finds testify to the presence of modern dogs as early as about 30,000 years ago, but probably since 2000 years man has started to select specimens for specific tasks such as hunting and guarding, for which it was necessary to improve certain behaviors that probably derive from it restricting the wolf’s predatory sequence and others. Only in the 19th century, in the Victorian era, did the search for a repeatable aesthetic ideal and purity of lineage begin: modern breeds were born and the notion that they were distinguished not only by a very specific physical appearance, but also by special ones behaviors.
really like that? Kathleen Morrill, a graduate student at the University of Massachusetts Chan Medical School and the Broad Institute of MIT and Harvard, and her colleagues, coordinated by Elinor Karlsson, wanted to test these hypotheses by working on a very large sample. They examined the genomes of 2,155 dogs and combined them with data from 18,385 physical and behavioral trait questionnaires that were compiled by owners of purebred and mestizo dogs and collected on the citizen science platform Darwin’s Ark. Behavioral traits considered include sociality towards people, activity level and impulse control (arousal), and willingness to respond to cues (drawing ability).
During the press conference dedicated to the study, Elinor Karlsson explained that she initially looked at human genetics related to the development of mental illnesses such as obsessive-compulsive disorder. Dogs are often used as experimental models for research into these diseases: they live in the same environment as us and their behavioral problems can have the same causes and similar drug treatments. Karlsson has never had dogs, but as soon as she told people she was studying them, they started flooding her with photos and information from her four-legged friends. The researcher and her team realized that this enthusiasm could be used to collect a large amount of data. This is how the Darwin’s Ark platform and publication in Science came about.
When the data were combined, only 11 genetic loci were strongly linked to behavior, but none of them could be closely linked to any breed. An exception seems to be bidability, which could be predicted by breed but which varies significantly from person to person. According to the results obtained, breed influences only 9% of a dog’s character, and in any case it was not possible to attribute a specific behavior exclusively to a single breed.
The question is actually much more complicated than we might think. Behavioral traits not only depend on the action of multiple genes, but are also influenced by the environment. Staying at a strictly genetic level, what turns out is that our dogs’ behavior was modeled over thousands of years of evolution and selection long before the Victorian breeds were forged. If we fooled ourselves into creating perfect crossbreeds in such a short amount of time to control a dog’s character and temperament, we’re wrong. What we have really been able to select for in modern breeds is only the aesthetic traits.
(The image of this report shows part of the photos sent by the people who participated in the Darwin’s Ark project. These photos were not only used for the study, but made the scientists’ offices the most memorable of UMass Chan Medical School credits: Elinor Karlsson)
April 28, 2022 (Change April 28, 2022 | 20:45)
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