TEMPERATURE INDUCED HETEROPLOIDY 



145 



METHODS FOR OBTAINING HAPLOID EMBRYOS 



EGG ACTIVATED BT 

 ARTinclAL MEANS 



EGG NUCLEUS DIVIDES 



PARTHENO- 

 GENESIS 



NORMAL RADIATED 



EGG SPERM 



EGG NUCLEUS ALONE DIVIDES 



RADIATED 

 EGG 



NORMAL 

 SPERM 



SPERM NUCLEUS At.ONE DrvlDES 



ANDROCENESIS 



EGG NUCLEUS ELIMINATED 

 BY DIVIDING EGG INTO 

 TWO PARTS 



UPPER HALf DEVELOPS WITH 

 SPERM NUCLEUS ALONE 



FOUR WAYS OF PRODUCING HAPLOID EMBRYOS 



Above are shown diagram matically the ways of producing embryos having 

 only one set of chromosomes instead of the two sets found ordinarily in 

 the higher plants and animals. 



From Fankhauser 1937: Jour. Heredity 28:1 



OBSERVATIONS AND TABULATION OF DATA: 



A complete record must be kept of the number of eggs treated, the exact time (in relation 

 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 heteroploidy 

 rests with the cytological analysis of the tail fin (tip). For the Urodela the tail tip is in 

 its best state for study at from Z\ to 3 weeks (just before the exhaustion of the reserve 

 yolk at the third finger-bud stage), and for the Anura some time after the external gills 

 have been resorbed. 



LATERAL LINE 

 ORGANS 



RED BLOOD 

 CELLS 



PRIMOROtA OF 

 LATERAL LINE SYSTEM 



Diagrammatical drawing of a salamander larva to show the 

 origin of the rudiments of the lateral line organs and of the 

 red blood cells which are present in the tailtip. The ampu- 

 tated tailtip includes cells from widely separated regions of 

 the embryos. 



From Fankhauser 1938: 

 Proc. Am. Philosoph. Soc. 79:715 



