Breeding Alters Dog Brains

Sabah Bari ’24

Figure 1: Offspring of dogs that were selectively bred to have desirable traits.

Over centuries, dogs have been bred to be domesticated and to be specialized in specific jobs. Stony Brook researchers have discovered that the dog’s brain structure is being altered through breeding, which allows the dogs to perform specific tasks. Selective breeding is the term used to describe how humans choose the parents of the dogs to create offspring with desirable traits. These desirable traits have the beneficial phenotypic traits and are strongly heritable. Researchers were able to see the brains of the dogs change quickly and how this played a role during breeding selection. 

By studying the brains of domesticated dogs, the researchers saw how they were faced with strong behavioral selection pressures, which ultimately led to the altering of specific parts of their brain. They examined MRI scans of 62 male and female purebred dogs from 33 breeds. To understand the changes the researchers saw, six networks of the brain regions were significantly covered. The six networks included the regions connected to the mesolimbic reward system, olfaction and gustation, movement, eye movement, vision, and spatial navigation, social action and interaction, limbic regions, and sensory processing regions. The researchers investigated the relationship among the six networks and the components of dog brains including its size, skull morphology, and total brain volume. The variation in the brain reflected the deep ancestry of the dogs and how their brains were highly statistically dependent on phylogenetic structure. 

The patterns the researchers saw among the six networks reflected how these regions were working simultaneously to create the different behaviors that are deemed desirable. These patterns included hunting and companionship. The researchers concluded that other components, like size of the skull and total brain volume, do not play a role in the behavioral traits but can only be shown through the six network regions of the brain. 

Work(s) cited:

[1] E. Hecht, et al., Significant neuroanatomical variation among domestic dog breeds. Journal of Neuroscience 39, 7748-7758 (2019). doi: 10.1523/JNEUROSCI.0303-19.2019.

[2] Image retrieved from:


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