Quote Originally Posted by Dingo View Post

Another thing is that it wouldn't technically have to offer increased susceptability to "factor X". It might only offer increased susceptability to the disease itself.

For instance Gene A does a great job until flu virus takes down Subsystem B. When Subsystem B goes down the protein that Gene A codes for becomes a liability and the victim dies of Disease C.

There is nothing wrong with Gene A, nor does it increase susceptability to flu virus. But if Subsytem B happens to go down the body fails. Nearly everyone who dies of Disease C also happens to have Gene A, but the actual problem is flu virus.

The other day I was reading about an eye disorder that worked just like that. Nearly every person with the disorder had a particular gene but most people with the gene didn't get the disorder. I can't remember what scientists thought triggered the disorder but it was something mundane.
words. words. words. . .

You are thinking of the sickle cell/malaria model. The benefit/cost ratio.

Penetrance--the genetic concept where a person inherits a genetic predisposition, yet the symptoms vary or the percentage of persons who exhibit symptoms.

I was upset about your comments because you said that there is no reason for a gene to be transmitted unless it has a biological benefit. That is neither true nor does it fit with the natural selection model.

The genes still transmit. There are exactly two reason why that wouldn't happen. One you mentioned previously, the individual dies (not a scoliosis problem). Second, the genetic variation makes the individual sterile, usually associated with mental retardation. NOT a scoliosis problem.

Genetic predisposition to scoliosis exists and are transmitted in a Mendelian fashion. The explanation is the the biology is complex and we have no clue what causes scoliosis.

This is why I am sooooooooooo against genetic testing for anything for which the genetic test does not give any hope of alternative treatments.

There are many examples of how people struggle to get a diagnosis and finally a genetic test says that you have disorder "suckstobeyou". "Oh, and by the way, there is no cure and no treatment, have a nice day."

I have to thank Karen for bringing up her family history. This probably a good example of a family with a strong genetic inheritance for scoliosis. And when you told her that her family could not possibly have inherited a "scoliosis gene", I was VERY upset because you, in fact, are wrong. Karen is right.