Artificial Transmutation of the Gene 



H. J. MULLER 



Reprinted by publisher's permission from Sci- 

 efice, vol. 66, 1927, pp. 84-87. 



One of the major tunmig points i?i the study of heredity was the 

 discovery that cha?iges i?j the genes could be i?iduced by artificial 

 jneans. This short paper by Muller describes the first de?no?istrably 

 successful attempt to make gefies mutate, and represejits the begin- 

 7iing of a new epoch in genetic history. Mutagenic methods and ma- 

 terials are now well know7i and widely used i?i genetic experiments, 

 and probably represent the most useful know?i tool in research. As a 

 consequence of this paper, the X-ray machine has become as com- 

 mon a piece of equipment ifi a genetics laboratory as is the micro- 

 scope in histology. 



It should be noted that Muller recognizes the dangers of X-ray 

 treatmetit to germifial tissues in this, the first paper o?i i?iduced muta- 

 tions. Midler's recognition of the dual ?iature of the effects of irradia- 

 tion is clear cut, for he points out in a paragraph on page 152 that 

 first there is a direct effect on the cells and tissues, and seco7id there 

 is a?! ifidirect effect on the desce?idant cells ajid tissues through the 

 mediatioji of the genes and chro?nosomes. The first of these is tra?7- 

 siefit (although possibly fatal), while the second is permane?it. It is 

 an ijiteresting commentary that there is still active and quite acrimo- 

 nious debate today as to the seriousness and coiisequences of this 

 afid other ki?ids of irradiatio?i da?nage. 



Most modern geneticists will modify decidedly, and in a sure and 

 agree that gene mutations form the detectable way, this sluggish "natural" 

 chief basis of organic evolution, and mutation rate. Modification of the in- 

 therefore of most of the complexities nate nature of organisms, for more di- 

 of living things. Unfortunately for the rectly utilitarian purposes, has of 

 geneticists, however, the study of these course been subject to these same re- 

 mutations, and, through them, of the strictions, and the practical breeder has 

 genes themselves, has heretofore been hence been compelled to remain con- 

 very seriously hampered by the ex- tent with the mere making of recom- 

 treme infrequency of their occurrence binations of the material already at 

 under ordinary conditions, and by the hand, providentially supplemented, on 

 general unsuccessfulness of attempts to rare and isolated occasions, by an un- 



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