Fearlessness and Anxiety as Genetic Factor for Dogs: A university research group conducted a study with 120 Great Danes that provided more evidence to support their hypothesis that anxiety and fearfulness is a hereditary trait in dogs. The study has identified a genomic region that underlies fearfulness and “includes several candidate genes associated with brain development.” While this development is important to understanding anxiety in dogs, it is noted that the environment still plays a very large role in traits in dogs. This study excluded puppy socialization which has already been found to significantly impact fearlessness.