it must be determined experimentally, but for any pair of genes ( A and B , for example) once it is determined, any repeat of the experiment will produce approximately similar results.
(it; must be determined experimentally; ) (it; is determined; ) (any repeat of the experiment; will produce; approximately similar results; T:once it is determined)
it it any repeat of the experiment
must be determined experimentally is determined will produce
approximately similar results T:once it is determined