Screening a puppys DNA methylome may help predict how energetic or fearful they will be

Anyone who's ever had a dog knows how different one can be from another. For example, they can be reserved or friendly, playful or calm, fearful or bold, and prone to bark or fetch or not. Research has shown that some of these differences are genetically determined. But even within dog breeds, where line breeding and artificial selection have led to the loss of much of the original genetic variation, the behavior of individuals can differ widely.

Now, researchers show that part of the differences in temperament – in particular their 'energy' level and fear-related behaviors – depend on acquired differences in the epigenome.

The epigenome, an individual's unique set of chemical tags on DNA and its associated histone complexes (nucleosomes), can dial the expression of local genes up or down. Because the epigenome is known to depend on age, diet, exercise, training, socialization, and other environmental factors, it can impact the activity and wiring of nerve cells and thus alter behavior.

Corresponding author Dr. Matteo Pellegrini, a professor at the University of California at Los Angeles, said, "Here we show that the behavior of dogs is associated with their epigenome, in particular DNA methylation. Our results open the door to using epigenetics to screen and select for desired behavioral traits in companion or service dogs."

Pellegrini and his colleagues quantified the epigenetic, genetic, and behavioral differences between 46 female and male dogs from 31 different breeds, with an age between one and 16 years.

Behavioral differences were quantified based on how the owners rated their dog in the Canine Behavioral and Research Assessment Questionnaire (C-BARQ) questionnaire, a widely used standardized tool that consists of 101 questions. The researchers used a form of machine learning, Partial Least Squares (PLS) regression, to identify significant associations between genetic or epigenetic variants and behavioral traits.

Image source: Anderson Nascimento.