In OGD V7 #298, on the theme of DNA-based taxonomy, Roy Lee said: "I would really like to know, within reason that the species I am using for breeding is as pure as possible to the name. .... If I/we are to believe that we are using superior clones today than were used decades ago, we should be able to predict outcomes better than originals or what it may do in a new cross. At present, I dont think we can be certain of anything. "
Roy, That sort of DNA-taxonomic enquiry is not what research botanists earn PhD's for doing. They are seeking answers to questions relating to the evolution of groups of orchids ... usually quite large groups, since that is where the genetic differences are greatest and therefore (supposedly) most meaningful. The closer together two taxa are, the harder it is to differentiate between them genetically. It is quite possible that one may not be able to find any statistically-significant differences between the DNA of two closely-related species. The kind of enquiry you are wishing for is the sort of thing that you pay someone to do privately. You have to provide them with leaf-samples of the two "pure" species, a leaf of the one you are interested in, and the leaf of something else to use asa control. If you are very, very lucky, you'll get a meaningful answer along the lines of "the 3 are identical to within 95% statistical significance", or "X and Y share 87% of the genome (ie, the bit we looked at), and both share 81% of the genome with Z." All too often, what you get is gibberish, and even though the price of such work has come down a lot, it can still amount to fairly expensive gibberish. BTW, even if you knew the answer to your question (eg, you knew that your "superior clone" contained 87% of the real species), it wouldn't enhance your powers of prediction because (a) you wouldn't know which 13% was different, and (b) there is no way of knowing if the 13% difference has any effect of the offspring of a cross.... all 13% may be from genes that are not expressed. Cheers, Peter O'Byrne _______________________________________________ the OrchidGuide Digest (OGD) orchids@orchidguide.com http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
