John asked: >I have been told & believed that the following is true as a 'very >general' observation... that the more white in the faces of the kits >or adults, that the better the chance that they could be deaf. Is >this a reliable sign? Geneticist, Dr. Brett Middleton has said that the amount of whiteness ear or on the ears is a good predictor usually. See: http://fhl.sonic-weasel.org/browse.php?msg=YG3069 including (I have standing permission to quote him.): >There are a zillion problems (scientifically speaking B-) associated >with various types of depigmentation. Failure of the neural tube to >close, cleft palate, enlarged colon, anemia, infertility, behavioral >disorders, reduced intelligence, limb malformations, problems with >balance, etc. It all depends on which gene or genes are causing the >depigmentation. and >There are some interesting aspects to hearing problems associated >with white markings, especially where the KIT gene is involved. For >example, I mentioned that this gene is involved with both spotting and >deafness in Dalmatians. However, the incidence of hearing loss in >Dalmatians with black patches on the ears is much lower. The KIT gene >is also responsible for the white head, belly, feet and tail switch of >Hereford cattle, yet I've never heard that deafness is a particular >problem for this breed. Note that Herefords have pigmented ears. and >While I don't know what genes are responsible for the markings of panda >bears, I do note that they, also, have pigmented ears. This seems to >indicate that genotypes exist that allow pigment cells to migrate to >the ear during embryonic development -- resulting in normal hearing -- >while restricting migration to the skin and coat sufficiently to >produce the white markings that many find desirable. >Unfortunately, we don't yet know how this works, though it probably >involves some modifier gene(s) that interact with the KIT gene. We also >don't know if ferrets are one of the species in which this could be >accomplished. (We also don't know how far we could go in eliminating >deafness in Dalmatians. Patches are considered a disqualification in the >Dalmatian breed standard! Talk about shooting yourself in the foot...) and >Behavioral problems associated with depigmentation are another >interesting phenomenon, and are related to all types of depigmentation and >The responsibility of breeders to consider the well-being of the >animal in their selection programs is an aspect of animal welfare that >is too often neglected. Too many people who would never consider >beating or starving their animals suddenly seem to lose all sense of >ethical limits when it comes to breeding them. There is a lot more in there and be sure to read other posts from Dr. Brett Middleton in both http://fhl.sonic-weasel.org and http://groups.yahoo.com/group/Ferret-Genetics/ [Posted in FML issue 4888]