CONCLUSION 



THE FUTURE OF GENETICS 



The Technical Synthesis The Three-Level Analysis 

 The Three-Level Synthesis 



A FINAL TASK REMAINS FOR US ill Completing our work : to show what 

 comicxioii its parts have with one another, how they arise out of 

 the past of the subject, and how they may be used to develop its 

 future. We must for this purpose remind the reader in the first 

 place of the combinations of method which have gone to build 

 up genetics. Secondly, we must recall the consequences of the many- 

 levelled structure we have built up. And fmally we must attempt 

 to pick out the central principles which support its framework. 



The Technical Synthesis 



The first combination is, of course, that of chromosome studies 

 and experimental breeding. Genetics might have been built without 

 the chromosomes ever having been seen (just as chemistry was 

 built without the atoms having been seen), but it could not have been 

 built without their having been imagined. The double foundation, 

 while giving the subject a technical duality, has also given it a 

 theoretical coherence and unity which expresses itself in all its later 

 developments. Above all, the connexion it establishes between the 

 determinant and its expression gives us a pattern of prediction which 

 covers the organism from conception to death. 



This first combination gives us genetics in the narrowest sense. 

 It takes us down to the molecular level and invites us to make the 

 next combination, that with chemistry. Chemistry enables us to 

 define our system in more precise terms and expands it at each 

 level. The chromosomes themselves, their movements, their pro- 

 ducts, their changes and, beneath everything else, their capacity for 

 self-propagation, are seen in terms of protein chemistry. And this 

 chemistry is of a uniquely biological character owing to the vast 

 size and adaptive organization of the molecules concerned. 



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