Units of Replication 33 



Fig. 2.4 I Meiosis. A, single-strand stage; B, pairing to form bivalents; 

 C, four-strand stage; D, opening of bivalents to show chiasmata; E, 

 first anaphase, disjunction of bivalents without centromere division; F, 

 daughter nuclei with crossover chromatids; G, second anaphase, 

 centromeres divide; H, four haploid daughter cells. (Adapted from 

 De Robcrtis, Nowinski, and Saez, 1954, General Cytology, 2d ed., 

 W . B. Saunders Company.) 



B 



D 



\n'; 



H 



