|MadSci Network: Genetics|
Hi Shawn, Normally, for mouse or drosophila genetics, homozygotes for a knock out or knock in gene are obtained through backcrossing (mating the offspring with the heterozygote parent). Needless to say that such method would be unthinkable in most human societies, for ethical and moral reasons. Even so, apart from these unavoidable considerations, the science behind transgenetics could maybe, just maybe, modify one gene per one or two generation of individuals. The exact repercussions of the change in one single gene would be unknown for a long time because the consequences of the gene mixing in the population could only occur at the later generations. The immune system, the senses of sight, hearing, smell and touch, almost every basic functions of the body are controlled by more than one gene and most often by more than 10 genes. The diseases that are caused by a single nucleotide polymorphism are, in fact, quite rare. Most diseases are multi-factorial, occuring due to the interaction of multiple environmental factors and multiple genes. Moreover, people that are sensitive to one disease could be resistant for another. Playing with biodiversity is, as monoculture with plants has demonstrated, dangerous. Our genetic pool has evolved over millenias, slowly but adequately adapting to changes in our environment such as new infectious diseases, warmer climate, etc. As for eugenics, transgenetics is a scientific possibility with some mammals and insects but is very difficult to translate to humans because of our life span, the requirements for the upbringing of our offspring, our culture, the fact that you cannot "force" someone to mate with someone else over multiple generations, etc. Hope this helps! Mike
Try the links in the MadSci Library for more information on Genetics.