F. Clarke Fraser, Ph.D., M.D. 



METHODOLOGY of EXPERIMENTAL 

 MAMMALIAN TERATOLOGYtt 



Experimental mammalian teratology deals with anatomical defects arising from 

 errors of development caused by exposing pregnant mammals, or their embryos, to 

 environmental noxious agents, or teratogens. (Mutant genes causing developmental 

 errors may also be considered teratogens, but the analysis of their effects is usually 

 categorized as developmental genetics and is beyond the scope of this paper.) 



Why should teratology be included in a volume on mammalian genetics? Be- 

 cause an environmental teratogen must act on a developing organism, and the response 

 that it produces will depend on, among other things, the genotype of the organism. 

 Thus, in studying the effects of an environmental agent on development, it is important 

 to take the genetic constitution into account, and much can be learned about develop- 

 ment and its errors by studying the interaction of an environmental agent with a 

 variety of genotypes. 



TYPES OF ANIMAL USED FOR TERATOLOGIC STUDIES 



A wide variety of mammalian species have been used for teratologic studies. 

 These include rats, mice, rabbits, guinea pigs, hamsters, pigs, and dogs. 681 There is 

 no apparent reason why other species should not also respond to teratogens. Choice 

 of a suitable species for experimentation depends on many factors, not the least of 



f Dedicated to Professor L. C. Dunn with admiration and affection. 

 X Financial support received from the National Research Council of Canada and 

 The National Foundation is gratefully acknowledged by the author. 



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