Scaredy dogs provide key steps towards modelling the genetic background of human anxiety.
New research from
psychiatrists at the University of Helsinki shows that fearfulness is a
genetically identifiable trait. The genomic region associated with fearfulness
lies on chromosome 11 in the DNA of Great Danes, one of the largest dog breeds.
Canine fearfulness and anxiety are not dissimilar from anxiety in humans, and
the researchers hope that their research may help shed more light on human
anxiety disorders.
Dog-lovers everywhere are familiar with
the particular joy that comes from befriending a stranger’s pup. Their bounding
up to you, all smiles and big paws, and the excited wags that follow as you
reach down to stroke them, are part of what makes interacting with a dog so
lovely.
However, not all dogs are determined to
make strangers their best friends. For some dogs – as for some people – the
idea of meeting new people, new dogs, or even encountering new surroundings, is
deeply anxiety-inducing.
These scaredy dogs attracted the attention
of Professor Hannes Lohi and his team from the University of Helsinki. Like
humans, all dogs feel fear. And, like humans, the amount that fear affects a
dog’s behaviour, and to an extent, the amount of fear that a dog feels, has a
large amount of natural variation. Some dogs are genetically pre-disposed to be
fearful, while others are naturally bold – ‘fearless’ – in disposition.
Fear in itself is a natural reaction – it’s what
motivates an animal to run from danger, and often plays a big role in keeping
us alive – but increased and over-scaled fearfulness can be detrimental. Dogs
that are particularly fearful often show problematic behaviour, which can make
them hard to control, and in a worst-case scenario can even result in aggression.
In humans, excessive fear characterises anxiety disorder, a mental health
condition that affects around 6% of
people in the UK.
Previous studies have shown that excessive
fear in dogs manifests in a similar way to human anxiety. This suggests that by
learning more about doggy fear, we may be able to better understand human
anxiety disorders.
To tackle the root of doggy terror, Lohi
and his team focussed on a particular breed of dog: Great Danes. These gentle
giants are one of the tallest dog breeds around, and weigh in at 100-200
pounds. Nonetheless, their sweet,
affectionate, and gentle temperament makes them excellent pets, and they are a
popular choice with owners.
Big these dogs may be, but brave they are
not – the research group was actually approached by a number of Great Dane
owners, who wanted to tell them about the fearfulness they observed in their dogs.
This anxiety was particularly heightened when meeting unfamiliar people; on
these occasions, the giant breed’s fear made it more difficult for their owners
to control them.
As the interest for the project had
sparked from the public, it was to the public that Lohi’s team turned to for
data. The study used the ever-more-popular ‘citizen science’ approach: Great
Dane owners contributed by completing a study of their dog, in which they gave
their furry friend a score according to the intensity of their fear in
different situations. 124 Great Danes were used in the study, from the fearful
to the fearless.
From the questionnaire answers, Lohi and
his team were able to assign each pup a ‘socialisation score’. This measure
included the dogs fear scores, as well as the amount of socialisation that they
had during their puppyhood.
Socialisation has a large effect on
fearfulness in dogs; puppies that are well socialised tend to be less
fearful in unfamiliar situations as adults. Socialisation is thus termed an ‘environmental
factor’ which affects fearfulness. The traits that an animal expresses are a
combination of their genetics and their environment. Thus, a puppy that is
pre-disposed to fearfulness may not become a fearful adult, if they grow up in
a social environment.
To accurately identify the genetics
responsible for fearfulness, it was important that Lohi and his team were able
to eliminate the effects of environmental factors like socialisation. By comparing
taking into account the socialisation of dogs, as well as their fear scores,
the team were able to weed out the effects of this factor and focus only on
genetics.
The genes responsible for fearfulness were
eventually pinned down to a tiny region of DNA present on chromosome 11. DNA
contains the instructions for life – within it, lies all the genetic
information passed on to an organism from their parents, which makes up their
unique traits. Chromosomes are tiny
structures that DNA is coiled around; they are present in the nucleus of every
cell in the body.
This is the first time that a genetic
explanation for fearlessness has been identified. Excitingly, this region also
has largely the same location on human chromosomes, which means that scientists
may be able to use it to look at variation in human anxiety.
While there is still much work to be done
- the team must search through this gene-rich region to pin down the specific
coding that contributes to fear responses – this is a promising step towards
modelling human anxiety.
Soon, the social anxiety of this playful
pup may be able to provide an important model for human anxieties, that will
allow us to understand fear both in dogs, and humans, better.
Reference: Saviaho, R., Hakosalo, K., Tiira, S.,
Sulkama, J., Niskanen, M., Hytönen, M., Sillanpää, M., Lohi, H. (2020). A novel
genomic region on chromosome 11 associated with fearfulness in dogs. Translational
Psychiatry. 10 (169).
Other resources:
https://www.eurekalert.org/pub_releases/2020-05/uoh-fgd052920.php
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