who can tell me molecular basis of "dominant" & "re - "dominant" & "recessive" (Aug/24/2004 )

they are quite old topics in classic genetic study, i'm wondering if people have find out the molecular basis to that, or any hypothesis?
bow to alllllll

hi, is this truley your question ? if i understand you right you want to know why some mutations are recessive and others dominant ?
if so i ll give ya an example for each case, i just hope i understand you right...
imagine a transcriptionfactor (tf) which is needed to transcribe a very important gene lets say another tf which is essential for proper development or whatever process. for its function it hybridizes with other tf s to form dimers or tetramers, if you have a mutation in one of the copies then 50% of this tf and the complexes formed do not work, due to the high robustness of molecular network the other 50% are still sufficient to carry out the function and so the mutation gives no or only a weak phenotype = recessive.

now imagine a tf which forms lets say homodimers or even better homo tetramers (for example lac repressor). if one copy of the gene is defect then not only 50% of the dimers or tetramers but almost 100% (i know its less, but whatever) will be not functional cuz one mutated tf will make the whole dimer or tetramer fail to work properly and its likely that one of those 4 tf s forming the tetramer will be mutant, therefore its dominant.

did i understand you right ? if not excuse me, but this is how i understood your question.