On 18 Dec 2009 at 15:36, Jim Clark wrote: > If I can quote a more credible source > than myself for my wording, Plomin writes: > > "The example of PKU serves as an antidote to the mistaken notion that > genetics implies immutability, as > discussed later." Well, it does hurt to be on the wrong side of the justly-eminent Robert Plomin. But if I must, I must.
Plomin also says in the article to which Jim directed us: "This form of mental retardation has been largely prevented, not by high-tech solutions such as correcting the mutant DNA or by eugenic programmes or by drugs, but rather by a change in diet that prevents the mutant DNA from having its damaging effects." and "As the example of PKU shows, even a disorder caused by a single gene can be circumvented by environmental intervention". Note the phrases "prevents the mutant DNA from having its damaging effects' and "can be circumvented". Both of these indicate that it is not the genetic disorder itself which can be altered but that its consequences can be dealt with by other means. The use of the term "immutability" is unfortunate, because if it is not immutable, then it must be "mutable", and that term is normally understood to refer to changes in the genetic material itself (a mutation). For clarity and to avoid misleading students, I'd think it best to avoid the M-word in this context, and save it for "correcting the mutant DNA" (gene therapy) as mentioned by Plomin. The important concept which Jim wants to convey to his students might be expressed by saying that the consequences of a genetic disorder can sometimes be reduced by appropriate treatment. Not as catchy, I'm willing to admit, but more accurate. BTW, _Science_ magazine has just announced today that gene therapy is one of the runners-up for breakthrough of the year. They cite three kinds: a) treatment of a rare form of inherited blindness in four children; b) X-linked adrenoleukodystrophy in two 7-year-olds, and c) "Bubble-boy disease", with eight children successfully treated. These are the genetic diseases which we can say with precision are no longer immutable. Stephen ----------------------------------------------------------------- Stephen L. Black, Ph.D. Professor of Psychology, Emeritus Bishop's University e-mail: sbl...@ubishops.ca 2600 College St. Sherbrooke QC J1M 1Z7 Canada ----------------------------------------------------------------------- --- To make changes to your subscription contact: Bill Southerly (bsouthe...@frostburg.edu)
