On 2 Feb 2009, at 10:08, Kenneth Hixson wrote: > Color breaking [and foliar variegation] occurs in a variety of plants, and is > not always caused by virus. To emphasize that point, a couple of analogous examples in other types of organisms: 1. Indian corn with multi-colored kernels on one cob. This is the phenomenon that inspired Barbara McClintock to do her Nobel prize-winning work on the regulation of genetic expression. 2. An ordinary pussycat (meow!) with a coat that is partly colored, partly white, or one that's multicolored (i.e. a calico). While simple Mendelian genetics was a good start, as time has gone on, it's become clear that it's not all about simple dominant and recessive alleles. Also, extra-nuclear factors have been found to play important roles in the expression of genes. Google "epigenetic" for further leads. -- Rodger Whitlock Victoria, British Columbia, Canada Maritime Zone 8, a cool Mediterranean climate on beautiful Vancouver Island http://maps.google.ca/maps/…