Monday, June 10, 2013

More Than The Sum

Okay, enough of this sappy stuff, let's talk some science.

Okay, one more picture of me in my happy place (courtesy of Crystal)
before we get back to work. 

As part of my brain sciences orientation, I'm catching up on some of the research that's already come out of the research center. I read a paper published in March of this year on the effects of the apoE gene on brain function (that's apolipoprotein E, if you're trying to impress your friends). People with apoE have been found to have an increased frequency of Alzheimer's disease. Upon further study, it was found that only a certain shape, or genotype, of the apoE gene showed an increase in Alzhemier's; this genotype has been designated apoE4. Another genotype of apoE - apoE2 - is actually thought to be protective against Alzheimer's.

Neat, huh?

The really cool thing about apoE is that there's not just one genotype (or expression or allele - I'm kind of over simplifying here). There's actually six different apoE genotype  apoE4/4, apoE4/3, apoE4/2, apoE3/3, apoE3/2, and apoE2/2. Our study showed that each genotype actually affects brain communication differently in mentally healthy women - not just people with Alzeheimer's disease.

So what does this have to do with dogs? Studying canine genetics is a lot easier than studying human genetics. For our apoE study, we needed to find people with healthy brains, measure their brain activity, and then study their individual genetic codes to figure out which of the apoE genotypes they had. With dogs, because of extensive breeding programs, we have a pretty good idea of which genes they have just by looking at them. People have been manipulating the genetics of dogs for centuries, and as a result, we have breeds - dogs that are genetically similar within the species. For example, I have Piper Ann, a boxer. I know by looking at her that she has the gene for squishy faces (that's brachycephaly, if you're trying to impress your friends). I know that Piper's both parents had the squishy-face gene, because the squishy-face gene is recessive - if you breed a boxer to a dog with a normal nose, the puppies are most likely going to have normal noses. And I know that if Piper weren't spayed, and I bred her with another boxer, those puppies would have squishy-faces, because that's how genetics work.

Genes rarely affect only one characteristic, though. We know that the human apoE gene is also related to heart health - a part of the body that seems practically unrelated to brain function. With dogs, we know that dogs from certain breeds (that is, with certain physical characteristics) will have certain genes for non-physical characteristics. For example, I know those squishy-faced boxers are more likely to be protective, athletic, and, um, maybe not so bright. I know that my long-back, short-legged weasel beast is likely to be talkative and intelligent just by looking at him - he's a corgi mix. Generally speaking, though, you can't tell what non-physical genes a human has just by looking at them; this is something that's pretty unique to highly domesticated animals like dogs (and chickens, horses, cows, pigs, and sometimes cats - oh, my!).

The squishy-face gene is possibly related to the rub-my-butt gene.

The research on apoE is exciting. If we know what apoE genotype a person has, we can take steps to prevent or treat mental decline before the person ever starts to show signs of Alzhemier's. (I know, there are other ethics involved in genotyping specific people - I'm looking on the bright side here). With dogs, knowing that certain physical characteristics are related to certain invisible characteristics allows us to identify problematic behaviors and act to prevent these behaviors before they appear.

Say what now?

Photo by Paige.

Okay, this is Zoe McRottenPuppy. She was a foster that I had back at the beginning of the year that I never blogged about because she just wasn't that interesting to me, and I was busy. I know by looking at her that Zoe is a Rottweiler - that is, she is black and tan, stocky, with a squarish head, and big feet. That's what Rottweiler puppies look like. I know that in addition to the gene for black and tan, Rottweilers often have a gene that allows them to display some pretty horrific resource guarding. I don't know if there is a specific gene responsible for this, or if it's a combination of genes or gene expressions (most likely), or if the resource guarding gene is anywhere near the black and tan gene - but I know it's probably there.

Knowing that Zoe likely carries the gene for resource guarding, I was able to take steps to prevent resource guarding before she ever started to display the behavior. We played trade games, food games, impulse control games, games that involved moving from one spot to another to prevent guarding of places - if it was related to resource guarding, we played it. As of today, Zoe has shown no signs of resource guarding. Whether this is because of the games we played, or because she doesn't have a strong gene for resource guarding, or because she doesn't have this gene at all, I have no idea. I will probably never know. But playing resource games certainly didn't hurt anything, and they may have prevented a serious behavior issue, so I'm calling it a win.

Human society has a love/hate relationship with genetics. On the one hand, we love the constancy of traits and characteristics that genes can give us. I adore my fat-headed, athletic, drivey dogs; I'm proud to be mostly Irish and all that entails. But at the same time, we hate the idea of being stonewalled by something that is out of our control. We cannot help the genetic card we have been handed at birth. Many people refuse to see the genetic predisposition American Pit Bull Terriers have for dog aggression, or German Shepherds toward human aggression, or terriers toward small animal aggression.

But we are more than the sum of our genes. The effects of the apoE gene can be increased or decreased depending on environmental factors like learning and mental stimulation. Environment does not rule all, either - the effectiveness of outside interventions may depend on the shape of the genes we carry. And with all the different genes and genotypes, and with all the variants in experience and environmental exposures, what it comes down to is that we are who we are - incredible individual, absolutely unique, and beautifully intricate. We are more than the sum of our genes or our experiences - and that is stuff of miracles.

Much gratitude to Ruth and Paige, who kept this post from sounding purely pretentious or stupid.
Any confusing parts are all me. I promise.

1 comment:

  1. So true that we're all ambivalent about genetic predisposition. I want my pit bull to love people (which she's very good at), but I don't want her to show a lick of aggression toward other dogs (which she's not so good at), despite generations of breeding encouraging people=love and dog=fight. It's a great reminder to all of us to fully accept what we get -- in our dogs, in ourselves -- and to make the most of it.