I’m sorry my disagreement makes you so touchy that you feel you must attack me personally.
You are using the words “quantitative” and “qualitative” wrong in the genetic context. Here is a definition:
“Quality vs. Quantitative Traits
All traits of swine are not controlled by just one gene pair. In fact, very few economically important traits are controlled by a single or few gene pairs. Traits such as age at 230 pounds, litter size, and average backfat thickness are controlled by possibly hundreds of gene pairs.
Consequently, traits are generally grouped into two categories, qualitative and quantitative.
Qualitative Traits
Qualitative traits have four distinguishing characteristics. These are:
1. Qualitative traits are controlled by a single or a few gene pairs.
2. Phenotypes (the visual characteristics we see), of qualitative traits, can be broken into distinct categories, in which every member in that category looks the same. For example, the red-black color condition in pigs is a qualitative trait and pigs are either red or black.
3. The environment has little effect on the expression of the gene pair(s) controlling a qualitative trait. In the red-black color example, red pigs would continue to be red, regardless if they were raised in environmentally controlled buildings or dirt lots.
4. The genotype of an individual for a qualitative trait can be determined (identifying the genes that occupy the gene pair(s)) with reasonable accuracy.
Quantitative Traits
Quantitative traits are dissimilar in their attributes when compared to qualitative traits. Characteristics of quantitative traits include:
1. Quantitative traits are controlled by possibly hundreds or thousands of gene pairs located on several different chromosome pairs. Some gene pairs will contain additive genes while others can contain nonadditive genes. Most economically important traits are quantitative traits.
2. The environment does affect expression of the gene pairs controlling quantitative traits. If two pigs are similar genetically, with one raised in a confinement unit and the other raised in a dirt lot, their growth performance will probably be different.
3. Phenotypes of quantitative traits cannot be classified into distinct categories since they will usually follow a continuous distribution. An example would be average daily gain. If average daily gain records from weaning to market weight of every pig in a group, were plotted the points would form a continuous line. An exception of this are some of the reproductive traits. For example, litter size is a quantitative trait but can be grouped into distinct groups of 7, 8, etc. It is impossible to accurately determine how many gene pairs are controlling a quantitative trait; therefore, an exact gene type can never be determined.
These factors make it difficult to identify individuals that have superior genotypes for quantitative traits. “
http://www.nsif.com/Factsheets%5CNSIF-FS2_files/NSIF-FS2.html
Qualitative changes require less genetic tampering than quantitative ones. How would less change pose more risk? How would controlled change pose more risk than uncontrolled, ie “natural” change? Why do you assume (this appears to be the assumption of many Greens) that natural change is both benign and not cataclysmic?
Interesting. And thanks for taking the time and trouble.
But if you were to read my post #11 again you could see that I am applying the qualitative/quantitative angle to the PROCESSES of inducing genetic mutation and not to the resulting traits. The resultant traits are qualitative and/or quantitative changes in either case.
Splicing genetic material from a spider to that of a tomato is qualitatively different from bombarding seeds with radiation. Genes are subject to natural radiation and stepping the the rads is just a quantitative change, in my humble abstract reductionist analysis.
Sometimes I feel that people are trying to misunderstand just to muddy things up just as Ms Brody does in her article, sorry.