TEMPERATURE INDUCED HETEROPLOIOY 



351 



METHODS FOR OBTAINING HAPLOID EM3RY0S 



EGG ACTIVATED BY 

 ARTIFICIAL MEANS 



EGG NUCLEUS DIVIDES 



PARTHENO- 

 GENESIS 



EGG NUCLEUS ALONE DIVIDES 



GYNOGENESIS 



RADIATED 

 EGG 



NORMAL 

 SPERM 



SPERM NUCLEUS ALONE DIVIDES 



ANOROGENESIS 



EGG NUCLEUS ELIMINATED 

 BY DIVIDING EGG INTO 

 TWO PARTS 



UPPER HALF DEVELOPS WITH 

 SPERM NUCLEUS ALONE 



MEROGONY 



FOUR WAYS OF PRODUCING HAPLOID EMBRYOS 



Above are shown rilagrammatlcallj the ways of producing embryos 

 having only one set of cliromosomes Instead of the two sets 

 found ordinarily in the higher plants and animals. 



From Fankliauser 1957: Jour. Heredity 28:1 



and thereby obviate the deleterious effects of foreign chroniosoines. If various genera 

 (or species) of Anura are available, such attempts should be made to carry normally non- 

 viable hybrids past the critical stage of gastrulatlon. 



OBSERVATIONS AND TABULATION OF DATA: 



A complete record must be kept of the number of eggs treated, the exact time ( In re- 

 lation to maturation) and duration of exposure, the number of eggs that cleave, and the 

 number of eggs that reach the various stages of early development. The final test of 

 heteroploldy rests with the cytologlcal analysis of the tall fin (tip). For the Urodela 

 the tall tip is in its best state for study at from 2|r to 5 weeks (just before the ex- 



