MENDELISM AND Ml TATlo.X 



337 



by T) which makes the resulting planl tall. The germ cells of the dwarf 

 plant carry something (/) causing the dwarf condition. In the firsl 



PARENTS 



r, 



L 



Fig. 12<). — A typical Mendelian cross between tall and dwarf peas, showing dominance 

 of the tall over the dwarf condition in the first hybrid generation (Fi), and the3:l ratio of 

 tall plants to dwarfs in the second hybrid generation (/•' ■■>. \t the right is shown the 

 corresponding distribution of tin- Mendelian factors for tallness (T) and dwarfness <n. 



hybrid generation (Fi) both factors arc present, T coming from one pa rem 



and / from the other, bu1 T "dominates" and prevents the expression of 



22 



