So Much for Mendel

[Wagonmaster]

It has been kind of a chuckle over the years on this site, watching the Internet experts talk about how genetics works in dogs. Everything always seems to come down to simple genetics, cause that is what Mendel came up with in his peas.

Well, it turns out Mendel is toast. Researchers have discovered that genetics requires both a receptor, and a switch, for a particular trait. Best description I read is that it is like a light bulb connected to a switch. If you don't have a light bulb but the switch is present, you can turn the switch on all you want and nothing happens. If you don't have a switch, you can have the light bulb but no way to turn it on. Moreover, just like your house system, there can be multiple switches for a given light bulb.

http://www.cnn.com/2011/HEALTH/03/09/pe ... tml?hpt=T2

Next they will be finding that sometimes what is attached to the light bulb is not a switch, but a rheostat. So one genetic outcome is that a trait (the light bulb) can be expressed in degrees, like a light can be dimmed or brightened.

So there goes all the testing for the presence or absence of specific traits based on simple genetics, out the window.

[jimssetters]

My belief only, all dogs have the light bulb! It is up to the trainer to find the right switch, and of course how bright your bulb is depends on the training.

[Cajun Casey]

Nutrigenics.

[Dave Quindt]

It has been kind of a chuckle over the years on this site, watching the Internet experts talk about how genetics works in dogs. Everything always seems to come down to simple genetics, cause that is what Mendel came up with in his peas.

Not everyone has been claiming that gene inheritance is the same as trait inheritance. Some of us have been reminding folks that it's trait inheritance that we really care about, and that we have no idea how trait inheritance really works.

[dan v]

So John....that's a lot of words to say, "We don't know what we don't know." Or the more we learn, we learn that we don't know?

[gittrdonebritts]

Why doe People Feel the need to always Prove others wrong ? is it cause they were bullied as a kid ? or cause they are just board and have way to much free time ? Although it was a great read, I'd Like to see more research and it may be a while till it is
"in the text books" so to speak, if you know what I mean. JMO
Joe

[Wagonmaster]

Yes, that is an unfortunate trait, found more so in dog people with an agenda than elsewhere.

I consider myself just a learner when it comes to genetics. There are things we know. And things we know we don't know.

And there are also things we don't know that we don't know. And because there are things we don't know that we don't know, it is always wise to be skeptical about the things we know that we know.

[dan v]

You know John. I've never seen you and Donald Rumsfeld in the same room together....kinda worries me now.

[Greg Jennings]

I don't think it invalidates testing for specific genes at all.

For example, if the dog shows up with a marker for a genetic disease, what in the world does the switch have to do with it? The dog has the gene. Period.

Now, is it expressed? Should the dog be bred? Different questions for a different day.

[Wagonmaster]

Well, that is the point. The research indicates that there is no such thing as "having the[\i] gene." If an organism (human or dog) "has a gene," viz. has a particular genetic expession, it would have to have both the receptor and the switch for that expression. So which is passed on, the receptor or the switch? Or both?

Simple genetics is premised on the assumption that it takes only one gene pair to create a trait or expression. If the organism has one dominant gene in the pair, the dominant version is expressed, if it has two recessives the recessive is expressed. This research indicates that there are actually at least two structures that need to be present, not one pair, but two pairs. And this for "simple" genetic expressions, in fact, there may be multiple combinations of pairs. Five "switches" for example, each of which turns the light bulb on in a different way.

I am no fan of perpetuating genetic defects, on the other hand, I am no fan of genetically engineering the world, or a given breed, using genetic tests to determine which dog(s) to breed. That assumes that the science is correct, and genetic science just isn't that far along. Better to me, is to use performance, testing, experience. These are based on outcomes, rather than on the assumption that we know what yields the outcome.

[Ayres]

Maybe people are going beyond this, but I thought breeders evaluated the dog itself (temperament, trainability, physique) to determine whether or not to breed it... and if it has been bred before then also evaluate the offspring. Are people really doing genetic testing (other than for health) to determine whether or not they should breed a dog?

[CHJIII]

Just goes to show you that the number one rule in my science classes is:


Nothing in science can ever be proven right; they can only be proven wrong.