551+ 



TEMPERATURE INDUCED HETEROPLOIOY 



Metaphase chromosomes from epidermal cells 

 of a haploid, a diploid and a trlploid 

 tail-tip (11, 22 and 33 chromosomes). 

 Tracinji,s of enlarged photomicrographs. 





Nuclei of epidermis cells from a haploid, a 

 diploid and a triploid tail-tip. The size 

 of the nuclei is rouglily proportional to 

 the number of chromosomes they contain. 

 Camera lucida drawings. 



Pigment pattern on the head of a haploid, 

 a diploid and a triploid larva, 4 weeks 

 old. Tracings of enlarged photomicro- 

 graphs. 



The same larvae as shown in Figure 3. Tlie 

 haploid larva (left) is dwarfed and edema- 

 tous, the triploid is slightly larger than 

 the diploid. Tracings of enlarged photo- 

 micrographs. 



TRITURUS VIRIDESCENS 



From Fanichauser 1939: Proc. Nat. Acad. Scl. 25:255 



Fanlchauaer and his students have analyzed the nucleoli, nuclei, cells, and organs of 

 the heteroplolda. They find that when there are extra sets of nucleoli and of chromosomes, 

 that the Increase in nuclear and cell size is compensated for hy a corresponding decrease 

 In cell number. This decrease must occur early, for in the later stages of development 

 the mitotic rate of diploids and triploids seems to he much the same. There are corre- 

 sponding differences in organ size except for the gonads and the notochord. Further "The 

 diameter of the wall of the pronephric tubules and pronephric ducts, and the thickness of 

 the epithelium of the lens of the eye thus remain about the same from the haploid to the 

 pentaploid levels." and "These observations show that in the amphibian embryo both cell 

 number and cell shape may be modified to allow the formation of organs of normal size and 

 structure. This indicates that both are subject to some control by the developing organ- 

 Ism." ( Fankhauser, I9U5). There is evidence that triploldy affects the females only, the 

 triploid larvae being undifferentiated or males. 



This field of investigation is extremely important from the physiological, morphologi- 

 cal, and genetical points of view. 



