MENDELIAN SEGREGATION 



11 



somes conjugate in pairs, as shown diagrammatically 

 in Fig. 5, b. The chromosomes then separate (Fig. 5,c 

 and d) at the time of division of the cell , and one of the 

 resulting daughter cells gets the chromosome bearing 

 the vestigial, and the other daughter cell gets the 

 homologous chromosome, bearing the long factor. 

 Hence, there will be two kinds of eggs in the female 

 and two kinds of spermatozoa in the male. When 

 two such hybrid flies mate with each other, any 



n 



.^ 





Fig. 5. — Diagram to iHustrate in a heterozygous individual the con 

 jugation and segregation of the chromosomes during "reduction." 



sperm may meet and fertilize any egg. The possible 

 combinations that result, and the frequency witli 

 which they occur, are shown in the next diagram 

 (Fig. 6, and also in Fig. 3.) 



As shown in this diagram, a sperm bearing the fac- 

 tor for long fertilizing an egg bearing the same factor 

 produces a fly pure (homozygous) for long wings; 

 a sperm bearing the factor for long fertilizing an egg 

 bearing the factor for vestigial wings produces a hy- 

 brid Hy (heterozygous) that has long wings, since, as 

 above, the long "dominates" the vestigial character. 



2.C 

 M 



].{.■)■ 



