THE CYTOPLASM 



precursor, plasmagenes differ from nuclear genes which multiply 

 with even pace in all living conditions. This, however, would be 

 a misconception. The nuclear gene also requires special precursors 

 to live, but the only evidence we have of their absence is the 

 breakdown of nuclear activity and reproduction, as a whole. 

 This breakdown is always found in deficient, and often found in 

 unbalanced, nuclei. The nuclear genes are specific in their food 

 requirements. They are even specific in the balance of these 

 requirements. They are non-specific only in the mechanical control 

 of their reproduction, which compels them all to live and multiply 

 in step with one another or all to die in step with one another. 



The second relationship which we can now see is that between 

 the plasmagene and the outside world. The plasmagene can adapt 

 itself directly to change outside the unprotected simple cell. But it 

 can do so only by suicide. The effect is Lamarckian, but it is an effect 

 of disuse only and not of use. 



In these circumstances we are bound to ask ourselves what the 

 unicellular situation would look like in a multicellular organism 

 undergoing differentiation. In flowering plants there are abnormal- 

 ities which develop during differentiation and affect different parts 

 of an individual, or of a divided clone, in different degrees. These 

 abnormalities must depend in an unspecified way on environmental 

 differences. 



Plasmagenes, being dependent for their multiplication in the cell 

 on its chemical equilibrium, should be subject to change in external 

 conditions. For single cells in the multicellular organism these 

 external conditions include development. A precise example is 

 afforded by the heredity and development of rogues. These rogues 

 are off-types which turn up unexpectedly as sports or mutants in 

 inbred strains or clones of many cultivated plants, such as peas and 

 tomatoes where they come from seed, and potatoes and tulips where 

 they come from tubers and bulbs. In peas their mode of inheritance 

 was made clear by the work of Bateson. 



The rogue pea appears in most garden varieties, and has more 

 pointed leaves and more curved pods than the type of the variety. 

 It breeds true when selfed. It also breeds true, as a rule, when crossed 

 either way with the type. There is no segregation in Fg, and we 

 must suppose that a plasmagene is at work. It must clearly be sup- 



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