182 



andrcx;enesis 



OBSERVATIONS AND TABULATION OF DATA: 



There are two criteria for successful androgenetic operations. 



1. Delay in cleavage and early development. The first cleavage may be delayed as 

 much as 45 minutes (at 22°C. ) and development through neurulation will tend to 

 be delayed. After hatching, the embryo will manifest those characteristics nor- 

 mally associated with experimentally induced haploidy such as in artificial par- 

 thenogenesis. These include stunting, dorso-ventral thickening, dorsal flexion 

 of the head and tail, oedema, reduction of the gills, etc. (see photographs of 

 abnormalities in development and haploid larva in section on Artificial Partheno- 

 genesis). Make drawings of androgenetic embryos and tadpoles. 



2. Chromosome count which should be haploid . This can be determined in the neurula 

 stage either by sectioning and staining the material, or by making coverglass 

 smears of neural crest cells (see Culturing Isolated Embryonic Cells) and staining 

 them with Harris' haematoxylin. Those tadpoles which survive for 10 days or 

 more can have their tails clipped and examined (see Tail Tip Chromosome Tech- 

 nique) for chromosome figures, without killing the tadpole. 





«Q 





o 



Z. 



Kg?5S;:-- 



■■W 







POLAR BODY FORMATION: RANA PIPIENS 



(From Porter, 1939: Biol. Bull. 77"233) 



Figs. 1-4. Semi-diagrammatic representations of four stages in second polar body formation of R. pipiens eggs. Draw- 

 ings were mode with camera lucida and give exact distribution of pigment granules, yolk platelets and 

 chromosomes, only part of which are shown. Selected from considerable material sectioned at 10 >i. (Eggs 

 inseminated and kept at 12°C. ) 1 125 X. 



Division spindle as in egg at time of insemination. 



Anaphase of maturation division. Stage at which spindle can be seen from exterior of egg as small black dot. 

 Egg fixed 35 minutes after insemination. 



Early telophase. Egg fixed 50 minutes after insemination. 



Polar body just forming. Egg fixed 56 minutes after insemination. 



REFERENCES 



BALTZER, F. G V. de ROCHE, 1936 - "Uber die Entwicklungsfahigkeit haploiden Triton alpestris. " Rev. Suisse de Zool. 43:495. 

 BRICCS, R. , T. KING, 1953 - "Factors affecting the transplantability of nuclei of frog embryonic cells." Jour. Exp. Zool. 



122:485. 

 EAST, E. M., 1934 - "The nucleus-plasma problem." Am. Nat. 68:289 C 402. 

 FANKHAUSER, C. GC. MOORE, 1941 - "Cytological and experimental studies of polyspermy in the newt, Triturus viridescens. 



II. The behavior of the sperm nuclei in androgenetic egy>. (in the absence of the egg nucleus). " Jour. Morph. 68:387. 

 KAYIOR, C. T., 1941 - "Studies in experimental haploidy i-i salamander larvoe. II. Cytological studies on androgenetic eggs 



of Triturus viridescens. " Biol. Bull. 81:402. 

 MOORE, B. , 1957 - "DNA in diploid and androgenetic amphibian hybrids. " Jour. Morph. 101:227-274. 

 PORTER, K. R., 1941 - "Diploid and androgenetic haploid hybridization between two forms of Rana pipiens Schreiber. " Biol. 



Bull. 80:238. (see also Biol. Bull. 77:223). 



