Everyone loves golden retrievers -- of course; they're usually gorgeous with goofy, lovely personalities.

But have you ever wondered what actually makes a golden retriever a golden retriever? And what makes them so irresistibly nice, by and large? We did -- and also wondered how genetically different dogs can be from one breed to another. Plus, where do mutts fit in? And what are the public policy implications of dog breeds, genes and personality?

Veterinarian Jessica Perry Hekman, who's also a PhD student in a genomics lab at the the University of Illinois, recently published a piece on dog breeds and genetics on her terrific blog, Dog Zombie. Though it focuses primarily on what happened when Victorians became obsessed with breedings dogs for looks rather than function (spoiler: bad diseases), Hekman also hinted at the relationship between genetics and personality, writing that she "can own a series of golden retrievers and predict with fair accuracy how each of them will look and act."

Intriguing, no? The Huffington Post caught up with Hekman to find out more.

The Huffington Post: What makes a golden retriever a golden retriever? Is it looks, or genetics, or...?

Jessica Perry Hekman: Genetics. They are all genetically similar. This makes them look similar -- and, to some extent, act similar.

How different genetically is a golden retriever from, say, a Chihuahua? How different are either of these dogs from a wolf?

It's a surprisingly complicated question. At the level of DNA -- the long string of letters that makes up our genetic code -- dogs are all very similar to each other (more than 99 percent) and very similar to wolves (also more than 99 percent).

Dogs and wolves are actually considered the same species. But obviously there are some real differences, just not ones that are reflected in large changes in the DNA that codes for them!

There's a lot of research going on right now trying to understand how very small changes in the genetic code can lead to significant changes in the individual (in dogs, in humans, in other species). The most interesting recent study in dogs found some genes responsible for small body size.

Behavior is a lot harder than body size as more things affect it. There is an interesting new study which suggests that the actions of a chemical called glutamate in the brain have effects on behavior, and has found a genetic basis for some of those differences.

Does being a purebred golden retriever guarantee that a dog will have certain personality traits? How much of a dog's personality is determined or influenced by breed?

Nothing guarantees certain personality traits, unfortunately. Breed and personality are certainly related, as anyone knows who knows dogs. But there are always exceptions.

Goldens are known as personable and biddable, but there are goldens out there who aren't particularly friendly and goldens who aren't particularly trainable.

Does the same hold true for mixed breed dogs? If a dog is, say, half golden retriever, can we make good predictions about that dog's personality?

It's even harder to predict personality in a mixed breed dog because the genes from the parents of different breeds can interact in surprising ways.

This is just a result of how genetics work. Basically, a purebred dog is purebred because his ancestors have been inbred until they are genetically identical for the traits that we care about. In other words, all golden retrievers have long hair -- that's one of the traits that we made sure to "fix" in that breed, because we liked it and decided that trait would be a defining trait of that breed. Meanwhile, we "fixed" the trait for curly hair in poodles.

Now, breed a golden to a poodle and you are mixing known gene versions with known gene versions -- mixing long hair with curly hair. You know 100 percent for sure what you'll get (in this case curly hair is dominant, so all the poodle/golden cross puppies will have curly hair).

But then you take these mixed-breed puppies and breed them to each other. Now you're not breeding purebreds any more. So now you don't know what the offspring will be -- they will be quite genetically varied. What will show up in the next generation, curly hair or long hair? You don't know.

That's just a mix with two known breeds involved. What about a mixed breed like my dog Jenny who has who knows what in her? Breed her to another mixed breed and you have a whole mess of different versions of genes interacting. Really hard to predict what you'll get.

What about pit bulls? Is there, according to veterinarians, a breed called pit bull? And are there any personality traits that pit bulls will share?

There is no single breed called the pit bull. They are a group of breeds, including the American pit bull terrier, the American Staffordshire terrier, and (depending on who you ask) a variety of other related breeds.

In addition, many mixed-breed dogs with a particular physical type (medium size, blocky head, short coat, muscular) are often referred to as pit bulls.

Personality traits shared among these dogs are under a lot of debate and you'll get different answers depending on who you ask. My personal experience is that they are high energy and intelligent.

Are there any dogs who are genetically likely to be dangerous? Does it make any sense to categorize breeds as such based on genetics?

Dogs who are not well socialized and dogs who are not used to living with humans are at risk of being dangerous. How we treat dogs has much more to do with their behavior than their breed.

That said, genetics does play a role in behavior as well, and I believe that some individual dogs are born with inherent risk of developing aggression. I don't think any breeds are at such a high risk of developing aggression that it makes sense to pass legislation about them -- it is much more effective to pass legislation supporting responsible dog ownership and establishing protocols for dealing with individual dogs who have proven themselves to be dangerous.

Are there any misconceptions about dog breeds and personality traits you run into very often?

I think people do tend to assume that individual dogs have the personality associated with their breed. It's not always a good assumption!

Dogs are individuals, even if many of them do come in these convenient breed groups. Think of a dog's breed as giving its personality a tendency to develop in particular directions, but no guarantee.

You write in your blog post that purebred dogs tend to be susceptible to certain diseases. What would you do about this problem, if you were czar of dog reproduction?

Labradors are more likely to get cranial cruciate ligament (CCL or ACL) tears; Great Danes are more likely to get gastric dilation volvulus (stomach bloat); Cavalier King Charles spaniels are more likely to have heart disease, specifically in a particular part of the heart called the mitral valve. I could go on.

There are two causes for genetic issues like these: either some bad traits were bred in by mistake and now are hard to get rid of, or the dogs were bred for specific physical traits which make them more likely to get a disease.

In the first case, responsible breeders the world over are trying hard to get these "bad" traits out of breeds, like cancer in goldens. In the cases of some breeds, this is really hard to do because the genetic pool of the breed is so small. I gave some clear-cut examples of this in my blog post (Basenjis and Dalmatians).

Then I asked: where do you draw the line? Should we be opening up more breeds to some outside genetics in order to improve them? I think we should, but I know there will be a lot of disagreement with that statement!

In the second case, I think we need to stop breeding dogs for physical traits that cause problems. Pugs and bulldogs just have overly flat faces and that makes it hard for them to breathe. We can easily breed them to have a bit more muzzle (and still look like pugs and bulldogs) so they can breathe normally, but we don't.

We have a culture of thinking "this problem is just part of the breed" instead of remembering that humans made dog breeds, and we can change them to be healthier!

If dogs are mostly being bred for looks at this point, instead of temperament -- and if you can really only select for a couple of traits at a time -- then why is it that golden retrievers are, by and large, so incredibly nice? Are they being bred for personality as well as looks?

So most breeds are, yes, bred for personality as well as looks. If you read the breed standards, personality is often in there. Which is why goldens are so sweet.

But I'll contend that in many cases, show-oriented breeders focus first on winning conformation competitions (how the dog looks); making a good pet is important to them, but if push comes to shove they'll choose winning the shows over breeding for a dog that's a good pet.

This is absolutely not true of all breeders and there are some lovely kennels out there where personality really does come first. But I think we can do better than we do, and have more of a focus on personality and less on looks.

It's not just breeders! Many owners go out to buy a dog who looks a certain way, and put that before the personality. We need to remember that you'll have to live with this dog and personality is a lot more important than coat color or head shape.

It seems like a big part of why people tend to care about dog breed is because they're looking for some kind of certainty, some reliability, when they bring home a dog. They want a golden retriever because they feel confident that a golden retriever puppy will grow into a dog who is good with their kids, and won't attack anyone.

Is this confidence misplaced? What should people do if they want to bring home a dog who will be good with their kids?

The best way to find a dog that is good with kids is to find an adult dog with a proven track record, and then manage him around your kids responsibly -- don't leave them alone together, make sure the kids don't harass the dog, and make sure the dog gets plenty of exercise and has his own space away from the kids sometimes.

This could be a dog of any breed.

If you want a puppy, you're always taking a bit of a chance on what he'll be when he grows up, just like you are when you raise a human child! You can stack the deck in your favor by getting a dog of a breed that will do well with your lifestyle, getting the puppy from a responsible breeder who has socialized him well, and giving the dog lots of training, socialization, and exercise. It's even harder to predict how mixed breed dogs will grow up, but plenty of people have gotten mixed breed puppies and raised them with kids with no problems when they make sure to train the puppy well.

If you have kids and you want to get a puppy, give a local trainer a call and ask if you can pay for a session with them to get their advice. Almost no one does this but trainers are often THRILLED to get these kinds of requests. Prevention is the best medicine and they'd so much rather help you get the right dog to start with than try to train out problems a year down the road!

Is there anything else you want people to know about dog breeds and/or genetics?

If I had to sum it up I'd say that personality is a really complicated thing, influenced by genetics and environment in ways we don't completely understand.

It makes it fascinating to study but it makes it really hard to predict what your new puppy will turn into when he grows up. That's what keeps life with dogs interesting, I guess.