286 Action of the Genetic Material 



In all the present discussions we have taken it for granted, as 

 the biochemical geneticists did, that the primary gene products are 

 certainly duplicates of the whole or of parts of the proteinic moiety of 

 the genie material. The possibility that the nucleinic acid part is 

 actually the genie material was not taken into account. I have already 

 mentioned the idea, actually the fact, that ribonucleic acid is removed 

 from the nucleus in some way and enters the cytoplasm. As RNA is 

 derived from DNA in the nucleus, we might think of RNA as the 

 specific first product of genie action ( assuming that DNA is the genie 

 material). This would require that as many kinds of RNA are dis- 

 missed into the cytoplasm as there are genie types. The known facts 

 are very difficult to reconcile with such a view (see, above, Caspers- 

 son). If all the RNA were accumulated in the nucleolus, one would 

 think that all its different specific types were mixed within the nucle- 

 olus; when it is removed into the cytoplasm, the problem of sorting 

 out the different RNA's arises, a process needed for orderly action in 

 genetic determination. All the facts (some to be discussed in the next 

 chapter) seem to speak against genie quahties of the RNA within and 

 without the nucleus, and to justify the old designation as trophochroma- 

 tin ( see III 4 B ) . This conclusion puts the discussion of plasmatic RNA 

 into the chapter on differentiation. The aforementioned discussion 

 (I 2 B a) of the work of Seiler and Ris and Kleinfeld showed that 

 masses of ribonucleic protein, almost as large in size as the remaining 

 chromosomes, or actually larger, may be sloughed off from the chromo- 

 somes in meiosis of Lepidoptera with clear indications that they have 

 no further function. 



