HEREDny AM) SKX 



235 



In the cast' of tlir nits (page 2:^(1) only a nunihcr of pairs of characters wliich may 

 sample of each class of F2 indixiduals is he concernetl in any one cross, but the 

 shown. The ratio is nine hlack-self- princii)les are the same: a given germ 

 colored to three hlack-hooded to three cell carries l)ut one of each pair, and 

 yellow-self-colored to one yellow-hooded, where both members of a pair come 

 for black is dominant over yellow and together in the imion of two germ cells 

 self-colored oxer hooded. to form an indi\idual, one of the char- 

 There is, theoretically, no end to the acters nsuall\- dominates oxer the other. 



From exhibit, American 

 Museum of iXaiunil Hisiorv 

 MENDELISM IN RATS 



If a pure gray ral be mated with a while rat the offspring will all be gray, for gray is dominant and white is 

 recessive. In the next generation there will be three grays to one white: the white and one of the grays are pure 

 and will breed true; the other two grays are hybrids. 



