ON THE IDENTIFICATION OF GENETIC AND 

 NON-GENETIC VARIATION IN BACTERIA 



M. Westergaard 



Institute of Genetics, University of Copenhagen 



When one has followed, even as an innocent bystander, the 

 discussion of the last 10-15 years on the development of drug 

 resistance in micro-organisms, one finds it difficult to avoid 

 the impression that much of the controversy is due to 

 semantic difficulty. Geneticists and microbiologists often 

 ascribe different meanings and values to the same technical 

 terms (see for instance discussions in Gale and Davies, 1953; 

 Sevag, Reid and Reynolds, 1955). Normally it is unprofit- 

 able to quibble about words, but this may be an exception. 

 It poses a problem with which the present author has been 

 concerned for some years, namely whether the genetical ter- 

 minology which was coined at the beginning of this century, 

 mainly by Wilhelm Johannsen and William Bateson, to 

 describe heritable and non-heritable variation in multi- 

 cellular, diploid higher plants and animals, is adequate today 

 to describe such variation in unicellular, haploid micro- 

 organisms. Genetics has entered microbial biology only 

 recently, and has brought with it its own language, which has 

 to compete with the terminology already established by 

 microbiologists who, until recently, did not think of variation 

 in micro-organisms in genetical terms. 



It may, therefore, be useful to consider the problem under 

 discussion in this symposium from a slightly different angle, 

 using the modern and in some respects less biased language 

 of information theory: cybernetics. Two reasons justify this 

 approach. Cybernetics has several times proved useful when 

 dealing with "border-line" scientific problems; indeed it has 

 sometimes been considered almost a psychiatric miracle-cure 



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