Heredity and Behaviour in Dog Breeds

Evan MacLean (University of Arizona), Noah Snyder-Mackler (University of Washington), Bridgett vonHoldt (Princeton University), and James Serpell (University of Pennsylvania) recently published a paper in Proceedings of the Royal Society B, looking at the heritability of 14 dog behaviours. The title of the paper is Highly heritable and functionally relevant breed differences in dog behaviour.

The authors compared behavioural profiles from 14,000 dogs (101 different breeds) with breed genetic data. Comparing behavioural profiles with breed genetic data for each of the 14 different “dog behaviours,” revealed levels of heritability above 0.50 for each trait.

The authors defined heritability as Genetic Variation (Vg) divided by Genetic Variation (Vg) + Environmental Variation (Ve). H = Vg/Vg+Ve

The behavioural traits examined were:

Stranger-directed aggression
Owner-directed aggression
Dog-directed aggression
Dog rivalry
Stranger-directed fear
Nonsocial fear
Dog-directed fear
Separation-related behavior
Attachment and attention-seeking
Trainability
Chasing
Excitability
Touch sensitivity
Energy level

More

For traits such as aggression toward strangers, trainability and chasing, the researchers found that genes contribute 60 to 70 percent of behavioral variation among breeds. Poodles and border collies, for example, had higher trainability scores, while Chihuahuas and dachshunds had higher aggression toward strangers.

Energy level and fearfulness showed a smaller genetic contribution, about 50 percent, suggesting that differences in environment or training play an equally important role in shaping those behaviors.

“Such strong correlations suggest that these were traits that people historically cared about and bred for,” says coauthor Evan MacLean, a biologist at the University of Arizona in Tucson.

The researchers then sought out specific genetic variants that might contribute to behavioral differences. Against thousands of variants, 131 stuck out as significantly associated with breeds’ behavior. No single gene was overwhelmingly associated with any behavior, suggesting that breed behavioral diversity arises from the complex interplay of many genes in addition to environmental differences. __ https://www.sciencenews.org/article/dog-breed-behavior-genetics

Dog Behaviours, Dog Genes, Human Genes

Genes have an effect on behaviours, no matter the species. This is true for dogs as it is true for crocodiles, lions, and rattlesnakes. We are just beginning to understand which genes are most important for which behavioural ensembles. Science needs to be free to do the necessary studies to make the connections clear.

In the study above, the authors discovered parallels between “behavioural genes” in dogs and analogous genes in humans.

The locations of these DNA hot spots make sense: Some are within or close to genes tied to aggression in humans, for example, whereas DNA associated with the dog’s level of trainability is found in genes that in humans are associated with intelligence and information processing.

The findings suggest behavior is guided by the same genes in many species, MacLean says. And if, for example, genes underlying anxiety in dogs lead to those same genes in people, that discovery may ultimately lead to better treatments for anxiety-related disorders, Serpell says. “These are the kinds of things we can see in the future.” __ https://www.sciencemag.org/news/2019/01/dog-breeds-really-do-have-distinct-personalities-and-they-re-rooted-dna

Supplementary materials for above study

Dogs Make a Good Model for Studying Genes and Behaviour

Because humans are so familiar with dog behaviours, and because humans have played an active role in selectively breeding dogs for specific behaviours and appearances for many centuries (probably for thousands of years), the study of links between dog genes and dog behaviours provides a good model for generating hypotheses to aid similar future studies in humans.

This is not politically correct, but it is good scientific thinking. If we are to solve the lion’s share of the problems we have currently created for ourselves, we need to understand how to avoid the delusions of mass thinking and dysfunctional mass behaviours that plague our world.

More: Trying to make the study of IQ in humans more objective

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