TECHNIQUES FOR STAINING CHROMOSOMES 



131 



As soon as the stain turns a deep purple, remove from the flame and cool rapidly 

 under running water. Just before using, add exactly 2. 5 cc. of olacial acetic 

 acid to 50 cc. of the above mixture. Dilute 1/2 to 1/3 for use. Mayer's acid 

 haemalum may be equally good if freshly made up. 



Transfer through two changes of tap water to which 5 or 6 drops of 1% sodium 

 bicarbonate (or ammonia) has been added to each 10 cc. of volume. This alka- 

 linization will make the stain an intense bright blue. 



Rinse in distilled water; dehydrate with 5 minute changes in progressively more 

 concentrated alcohols to 95% where two changes are made, followed by 3 or 4 

 changes in absolute alcohol. Transfer to carbol-xylol for 5 minutes, then into 

 two changes of xylol. (If the atmosphere is not humid and the transfer can be 

 made directly from the absolute alcohol to xylol, the stain is apt to be more per- 

 manent. ) 



Mount in clarite on cleaned slides under slightly compressed (cleaned) cover 

 slips. Several tail tips may be mounted on a single slide which can be marked 

 with diamond point for identification. 



(■ENTAPLOIO TETRAPljOID TBIPL01D 



-'•'-' ■----'' /"'•. '"^- '-'•--, 'i^-- •"-'. ,'-'-'..rA-. '<>0'-O! 



{OiOj'Jiyh]'-^ 



RELATIVE SIZES OF NUCLEI AND CELLS FROM 



THE TAILFINS OF LARVAE OF TRITURUS 

 VIRIDESCENS WITH DIFFERENT NUMBERS OF 

 CHROMOSOME SETS 



Above: Surface view of nuclei of epidermis cells. 

 Nuclear size increases approximately in proportion 

 to chromosome number. Below; Nuclei and cell 

 boundaries of single gland cells (Leydig cells). 

 Cell size increases with nuclear size. 



(From Fankhauser 1945: Quart. Rev. Biol. 20:20) 



Body cavity of pentaploid distended 

 with fluid (ascites). In both larvae 

 the melanophores are "expanded". 

 Tracings of photomicrographs. 



"TRITURUS VIRIDESCENS" 



(From Fankhauser 1940: 

 Proc. Nat. Acad. Sci. 26:326) 



REFERENCES 



COSTELLO, D. P., C. HENLEY, D. E. KENT, 1957 - "The effects of p^^ on mitosis in tail -tips of larval salamanders. " Jour. 



Exp. Zool. 136"143-170. 

 COSTELLO, D. P., D. G. HOLMQUIST, 1957 - "Spontaneous and cold-induced heteroploidy in Triturus Granulosus. " Jour. 



Elisha Sc. Soc. 73:363-378. 

 FANKHAUSER, G. , 1940 - "A Pentaploid Larva of the Newt, Triturus Virdidescens. " Proc. Nat. Acad. Sci. 26:526 

 FANKHAUSER, G. , R. R. HUMPHR€Y, 1959 - "The origin of spontaneous heteroploids in the progeny of diploid, triploid, and 



tetraploid axolotl females. " Jour. Exp. Zool. 142:379-422. 

 GALLIEN, L. , par 1959 - "Recherches sur quelques aspects de I'hetero ploidie experimentale chez le Triton Pleurodeles waltii." 



Jour. Emb. & Exp. Morph. 7:380-393. 



