Ok guys, once again I must admit I have a flaw, in that genetics was not one of my favorite science projects, frankly if you couldn't mix two chemicals and make a foul smelling smoke.. well where was the fun ;) anyhow, thanks to Sukie for forcing me to reread some stuff on genetics, and Sukie is indeed very well informed, thanks.. tho, I still have a question.. Sukie writes >Melissa and Linda are right! We will NOT be able to breed out deafness. >We can reduce the rate but actually removing any allele from a population >is actually difficult and having variable expression only makes it that >much harder. As near as I have been able to ascertain ? the genes for "most causes of deafness" are recessive, and only brought out in crossbreeding parents with the recessive gene, thus increasing the likelihood of the recessive becoming the only gene pair, and therefore dominant. breeding with a parent with a dominant gene pair of "defective" genes, with any other parent (with the recessive gene) will still result in a certain percentage with that "defective recessive" as a dominant gene pair. ( well, not really dominant, in so far as the technical aspects go, but rather, the "only" gene available to the next generation ? i.e.: breeding two ferrets with a recessive gene can allow for some of the kits to be born with ONLY the recessive genes, and therefore there will be no option but to pass that gene on. whereas breeding a ferret with no recessive gene for that defect with another with that gene, can still result in carriers of the recessive. so yes, it may be hard to breed out things like deafness as you will not know who the carriers are, and breeding two carriers can result in a recessive gene pair. However, my point was, ( and this is much easier with ferrets then some other animals, as they have a lot of kits per litter and statistics are easier per large litters). If ANY of the subsequent kits are deaf.. then NONE of the others from that litter should be bred as they are all now (or mostly) now obviously carriers. If none of them are deaf, and there is no history of deafness in the family, then breed those kits with others ( but use a remote family/bloodline) with equally non-deaf statistics..) therefore increasing the number of non deaf gene pairs. As soon as there is any incidence of deafness, the entire bloodline should be shut down.. then, eventually there will be NO recessive gene left for deafness..(or at least that particular genetic strain of deafness) Darrin PS: people are not ferrets, thusly so, ferrets are not people and we (as the domesticator of ferrets) have the ability as responsible breeders, to "control" the genetic makeup of domesticated animals, keep in mind this would take "generations" to work out, but the sooner we start the sooner ferrets owners will never have to worry about genetic deafness ( or other issues) again.. Our current generation is creating years and years of work for the (hopefully) more responsible future generations of breeders that will need to breed out these traits that we have so irresponsibly bred back into the gene pool. [Posted in FML issue 4669]