Gene expression and behavior in subspecies

Study may explain why wolves are forever wild, but dogs can be tamed.” January 17th, 2013. Excerpt:  “…the difference may not be in the gene itself, but in when the gene is turned on.”

Ethology (International Journal of Behavioural Biology) article graciously provided by Kathryn Lord.  Excerpt: “The early development of sensory input, motor output, and the synthesis of this information plays a role in the foundation of adult behavior. For example, early in their development mammals experience a critical period of socialization…”

My comment: This article reviews data on experience with olfactory/pheromonal input during socialization, which alters gene expression and differences in the behavior of these closely related subspecies. Wolves and dogs respond to pheromones from birth. However, wolves begin socialization while blind and deaf. Thus, olfactory/pheromonal input epigenetically turns on gene expression in the absence of visual or auditory input. Dogs do not begin socialization until what they see and hear can be paired with the epigenetic effects of olfactory/pheromonal input on gene expression.

When altered gene expression occurs only in response to the species-specific pheromones, behavior is more finely tuned to  conspecifics.  Heterospecifics are more likely to present a threat, which is first associated with their scent and subsequently associated with their visual and auditory impact on wolves. The combination of scent, visual, and auditory impact on dogs during socialization lessens the relative impact of scent. This allows dogs to socialize in the presence of heterospecifics that they do not perceive to be threatening.

Novelty is the threat to wolves and their behavior is adapted to what is typically a lack of heterospecific exposure. Novelty is not a threat to dogs because it is first associated with scent, auditory, and visual input during socialization. This fact makes dogs better suited to be loving pets that are wolves.

The take home message is one that helps us to distinguish among the relative salience of auditory, visual, and olfactory/pheromonal stimuli during the early developmental staging of behavioral development that is specific to these subspecies.  Clearly, the behavioral development of wolves is more dependent on the epigenetic effects of olfactory/pheromonal input on gene expression during the first two weeks of life. In the absence of associations with visual and auditory input during the first two weeks, the epigenetic effects of odor cues remain the best predictors of behaviors across a lifetime of adaptively evolved behaviors in wolves and dogs, and the epigenetic effects of odors on gene expression determine which subspecies will make the best pet.

This does not mean that the epigenetic effects of olfactory/pheromonal stimuli on gene expression throughout life are any less important to dogs than wolves or people. What it means is that early exposure and genetically predisposed responses to olfactory/pheromonal stimuli are better predictors of adult behavior than is exposure to visual or auditory stimuli in any species. That’s because olfactory/pheromonal input has direct effects on gene expression whether or not the input is associated with visual or auditory input in species from microbes to man.

Author: James Kohl

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