I] 



and its Consequences 



15 



resultant seeds are F^, showing the dominant character 

 yellowness or roundness, but the seed-skins are maternal 

 tissue. Such F^ seeds grow into F^ plants and bear F., 

 seeds which show the typical mixture of dominants and 

 recessives in the pods (Fig. 3). In each case Mendel's 



J 3 t X 0^% 



YT? 



) n 



> 



YR 



\^ <\R 



Y?? 



YK 



^fe 



<?*i c/w 



c|R YW 



YR 



I) 



YR 





Fig. 



3. Inheritance of seed-characters in Pea. The seed of a green 

 round variety fertilised by pollen of a yellow wrinkled variety are 

 yellow and round (i^j). The reciprocal cross would give the same 

 result. Two pods of F^ seed borne by the F^ plant are shown. There 

 were 6 yellow round, 3 green round, 3 yellow wrinkled, i green 

 wrinkled. 



observations have been substantially confirmed by later 

 observers, and the operation of similar processes has now 

 been recognized in a long series of most diverse characters 

 in both animals and plants. H 



^C 



/} Consequences of Segregation : Homozygote and 



Heterozygote, 



Before considering the various extensions of Men- 

 delian research, it may be well to indicate in general terms 

 the chief significance of the facts. The first conception 

 to which we are led is that of tinit-charactc7's, units 

 because they may be treated as such in the cell-divisions 

 of gametogenesis. It is evidently upon some process of 



