A study of more than 3,000 dogs found that genetic variants cannot reliably explain individual behavioral traits, calling into question claims by consumer dog DNA tests that market personality or behavior scores. Current dog DNA testing has several significant limitations. The technology remains in its relative infancy, with many conditions lacking known genetic links, and new mutations continuing to be discovered, making it difficult for genetic tests to provide accurate assessments.

The research team included genomicist Kathryn Lord of the University of Massachusetts and drew on behavioral surveys collected through the Darwin’s Ark project. The scientists matched genomic information with owner-completed questionnaires and concluded that, while genetics can predict physical characteristics, behavior does not map cleanly to single genetic variants. This study largely confirms and extends previous large-scale work, such as the Darwin’s Ark/Science study led by Karlsson, which shows that breed explains only a small fraction of individual dog behavioral variation and that behavior is highly polygenic, spread across many genes with tiny effects.

“Genetic tests for behavioral and personality traits in dogs are now being marketed to pet owners, but their predictive accuracy has not been validated,” said Kathryn Lord, genomicist at the University of Massachusetts.

Researchers relied on the Darwin’s Ark project to enroll dogs and gather standardized behavioral surveys directly from owners, then compared those responses with genetic data. The work supports the observation that “no single genetic variant can explain why he is the way he is,” one of the study’s clear findings.

That mismatch has practical implications for how people interpret consumer DNA test results. “For example, if a dog is labeled as genetically predisposed to aggression, an owner might limit essential social interactions, or a shelter might decide against adoption,” Lord said. To improve understanding of a dog’s behavior, owners can utilize scientifically validated questionnaires like the Canine Behavioral Assessment and Research Questionnaire (C-BARQ), widely used by researchers to assess temperament based on their observations.

The study’s conclusions challenge the scientific basis for marketed behavior scores and raise questions about relying on genetic reports for decisions about training, socialization or placement. By testing predictive claims in a large sample that linked genomes to owner-reported behaviors, the team addressed the central marketing pitch of many direct-to-consumer canine DNA companies.

The researchers placed their findings in the context of broader scientific work on behavioral assessment and testing, an area discussed in the scientific literature on dog behavioral testing and methodology (Nature). That body of work explores how owner questionnaires and structured tests can be used in behavioral research, but the new analysis shows genetic signals of the kinds used in commercial reports do not produce reliable, individualized behavior predictions.

Darwin’s Ark project materials supplied the behavioral data that made this analysis possible, allowing researchers to test how well polygenic scores and identified variants correspond to questionnaire-based measures of temperament and personality. This study lays bare the shortcomings of current dog DNA testing methods and demonstrates how they can mislead dog owners.

The findings place a limit on how far genetic testing can go in explaining why a particular dog behaves as it does. They also underscore the potential for misinterpretation when genetic information is presented as deterministic: owners, trainers, and shelters could make consequential decisions based on scores that the study found lack validated predictive power.

The study team included researchers affiliated with the University of Massachusetts and worked with the Darwin’s Ark project to collect and analyze the data. Kathryn Lord, whose affiliation is listed as University of Massachusetts, is a coauthor and spoke directly about the practical risks of unvalidated behavioral labels.

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Original reporting: view the original article.