Genetic Systems II I 203 



Fig. 9.9 I Diagram of three types of parthenogenesis and their genetic 

 consequences. Type la, somatic number restored by fusion of second 

 polar body nucleus with egg nucleus; type lb, somatic number restored 

 after cleavage division of egg by fusion of cleaxage nuclei; ameiotic type, 

 divisions resulting in egg are mitotic. (From White, 1954, Animal Cytol- 

 ogy and Evolution, 2d ed., Cambridge University Press. ) 



Parental 

 chromosomes 



Diakinesis 



First 



meiotic 

 division 



Second 

 meiotic 

 division 



Chromosomes 

 of offspring 



b' 



b' 



b 



a- 



I 



Egg 



2nd polar 

 body 



b' 



1st polar 

 , body 



6' 



I 



Egg 



2nd polar 

 body 



b' 



1st polar 

 , body 



6- 



C>T- 



b- 



c^J- 



o-r 



/I 



6' 



b' 



Single 



, polar 



body 



MEIOTIC 

 Type la 



MEIOTIC 

 Type 16 



a' b' 



AMEIOTIC 



