Link to the paper in Science: Ancestry-inclusive dog genomics challenges popular breed stereotypes.
Environment and socialization remain the largest determining factor.
Unsurprisingly, most stereotypes about dog breeds are pseudoscience that come from the eugenics movement. In particular, “popular knowledge” around pitbulls and bulldogs is just thinly veiled racism.
interview on the study from the verge: https://www.theverge.com/2022/4/28/23043508/dog-breed-behavior-genetics-study-stereotypes
The research did find some genes associated with traits like human sociability and howling frequency. But overall, only around 9 percent of dog behavior was explained by breed.
“Dogs are individuals,” said Marjie Alonso, a study author and executive director of the International Association of Animal Behavior Consultants. “What a dog looks like is not really going to tell you what the dog acts like.”
Edit: modern “purebred” breeding literally came from eugenicists, that’s why this old political cartoon even exists. Documentary on pedigree dogs and their many issues: https://vimeo.com/166015460
To preface, I owned rottweilers, but I would never trust a pit bull. "That's anecdotal" yes it is. I'm staying the hell away from those fuckers. I don't know if it's genetic, or that pit bull owners are just fucked in the head, or can't take care of dogs responsibly, or something else entirely, but a fact is that most deathly incidents happen with pit bulls.