What causes certain dog breeds to pursue squirrels?

Untangling the convoluted genetics braided by hundreds of years of dog breeding is a huge challenge, as is cataloging the genetic alterations (many of which are involved in neurodevelopment) that underpin the behavioral features of different breeds.

As explained by geneticist Elaine Ostrander, an author of the study based at the US National Human Genome Research Institute in Bethesda there are around 350 dog breeds identified throughout the globe, and each has a different background. They can't be  lumped together like people.

Each distinct history has left its mark on the genomes of individual breeds. Some breeds have been greatly affected by a single male who performed well in a dog show and had his sperm preserved and extensively shared. Others may have been impacted differently: for example, during times of war or famine, when there was insufficient food to feed dogs, the populations of several massive dog breeds declined substantially. Breeders could then cross various canine lineages in an attempt to restore lost features to the residual population.

Afterwards, Ostrander and her collaborators used behavioral surveys completed by the owners of over 46,000 purebred dogs to correlate behavioral features to lineages. Terriers, for example, exhibited predatory behavior and hostility toward other dogs, while toy dogs exhibited nervousness.

An examination of the DNA sequences related with those behaviors revealed a number of variations connected with nervous system development. Variants found in sheepdogs raised for their herding skills, for example, identified a biochemical pathway important in the formation of nerve cell connections. Previous research has found a relationship between two genes implicated in this system and the behavior of mother mice gathering their pups closely together, indicating that herding is involved as an evolutionary tool of maternal protective instinct.

According to geneticist Elinor Karlsson of the University of Massachusetts Chan Medical School in Worcester, the findings represent a significant step forward in understanding the links across dog lineages. Karlsson previously published data demonstrating that breed is a poor predictor of a particular dog's behavior.

The researcher claimed that dog genetics used to pose a substantial problem, while these findings are  moving beyond the concept of comparing one breed to another, and further towards properly examining how behavior translates into canine genealogy.

Greater differences

This study concentrated on single-letter variations in DNA sequences as well as tiny deletions or insertions of DNA. According to a canine geneticist Adam Boyko at Cornell University in Ithaca, New York, future research may focus on other types of genetic diversity, such as bigger deletions or chromosomal section rearrangement.

As similar studies continue to explore the genetics behind canine behavior, Boyko hopes that the findings will guide study into neurodiversity and the molecular foundation for human behavior. “It gives human researchers the ability to start generating hypotheses that you wouldn’t otherwise be able to have in the absence of this great model.”

Given that dogs and people frequently share accommodation, such research might be beneficial in understanding how the environment influences illness risk. According to Karlsson's comments, dogs and humans might propably be more similar than different, as they mostly completely understand one other.