84 GENETIC STOCKS AND BREEDING METHODS 



rabbit, and so forth. Consequently, a compilation of this information would be most 

 timely and of considerable interest to all concerned. The publication of Billingham 

 and Silvers," the Catalogue of Uniform Strains of Laboratory Animals Maintained in Great 

 Britain, 742 and the more recent questionnaire of the Committee on Maintenance of 

 Genetic Stocks, Genetic Society of America, provide some information on the where- 

 abouts of such material, but it is believed that many unlisted stocks of genetic interest 

 are being maintained by various investigators. 



Thus, the Genetics Study Section, Division of Research Grants, National Institutes 

 of Health, thought it most pertinent to develop a composite listing of genetic material 

 for mammalian species most commonly used in laboratory experimentation, and to 

 include such listing in this volume. This material is the initial effort to bring together 

 all the information alluded to above, plus the results of an extensive inquiry to scores 

 of investigators and organizations around the world. It is hoped that this compilation 

 is complete, but it is realized that some investigators were no doubt inadvertently 

 overlooked. I apologize for this oversight and hope their material will be included 

 in the planned revision. 



In developing this listing, many sources of information were utilized as well as the 

 talents of many individuals in the United States and abroad. To all of these sincere 

 thanks and appreciation are extended for permission to use their material and for their 

 efforts and interest. Thanks are also due to Mrs. Clarice Overath and Mr. Robert 

 Dettman for their untiring help in assembling the data and preparing the manuscript, 

 and various others at the National Cancer Institute who have been helpful. 



LISTING ARRANGEMENT 



The arrangement of this composite listing is by sections according to species as 

 follows: Section I, Mice; Section II, Rats; Section III, Guinea Pigs; Section IV, 

 Hamsters; Section V, Rabbits; Section VI, Peromyscus sp. Each section contains a 

 brief introduction, followed by tables listing (1) established inbred strains, (2) strains 

 in development, and (3) stocks of particular genetic interest. 



The distinction between established inbred strains and strains in development 

 was made on the basis of the definition of an inbred strain as recommended in Stan- 

 dardized Nomenclature for Inbred Strains of Mice, 219 that is, twenty or more consecutive 

 generations of brother x sister or parent x offspring (provided the mating in each 

 case is to the younger parent) . Two exceptions to this rule were made for rat strains 

 MR and MNR, since the generations of inbreeding presently reported are appro- 

 ximately the theoretic twenty generations. It is likely that by the time these listings 

 are published twenty generations of inbreeding will have been completed. Thus, 

 the strains in development are those exhibiting various generations of inbreeding from 

 Fj to something less than F 20 . In the case of certain strains of rabbits (table 38), when 

 matings of brother x sister or parent x offspring have not been consistently followed, 



