Phase- and Tissue-specific Protein Patterns

One can still go to a step further and carry out comparative analyses of the first secondary gene products, the polypeptides or proteins. Consequent on the introduction of a suitable method, namely, zone electrophoresis on different supports, phase- and tissue-specific protein patterns have been detected in a wealth of experiments in recent years. As an example tissue-specific patterns of soluble proteins from different parts of the tulip are shown (Fig. 147). Enzymes, of course, also number among the proteins. We have already dealt with isoenzymes, multiple 

differential gene activity is also demonstrable at the level of the proteins. One can depart still further from primary gene activity and consider the formation of visible characters. Character formation proceeds in an orderly sequence, first the development of character A, then that of character B, etc. According to our general concept differential gene activity should lie behind this visible sequence of events. Experimental evidence for this was obtained in a number of cases using antimetabolities of 

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