Quote Originally Posted by pavel View Post
Interesting, though I do have a Q, Amey.

You said "3" genes and have presented T1-T3 and t1-t3. So are the capital and lower case designations for dominant and recessive as is often used in genetics or are there actually 6 genes. If the former case, would then the result for an orchid with nothing but two sets of T1-T3 be only outer tepals?
Actually Paul, there are 4 clades (groups) of B genes (the total number of B genes varies in different orchids). Genes of clade 1 and 2 are expressed in the outer tepals, 1,2 and 3 in inner tepals and 1,2,3 and 4 in the lip. The capital T and small t , has nothing to do with the genes, it is just used to denote the tepals, capital for the outer, small for the inner tepals. It is much more complicated because these different B gene clades autoregulate the expression of one another. For eg. The clade 1,2 genes do no allow the clade 3 and 4 genes to be expressed outside the inner tepals and the lips. This is a natural feedback mechanism, but due to repeated mericloning (vegetative reproduction, no sexual reproduction) the mutations accumulate such that one of the gene clades either looses its function completely or partially, thus giving rise to these peloric mutants.