Some Laws of Heredity 



43 



of this generation are pure recessives and only 

 give white when interbred. One-third of the 

 blacks are pure dominants and give when 

 mated only black offspring; but the rest are 



hybrids and give again, when interbred, three 

 black to one white. It does not follow that 

 because white is a recessive in guinea pigs it 

 will always be such. Thus if a white leghorn 

 chicken is crossed with a black minorca the 

 children are aU white, the grandchildren three- 

 fourths white, one-fourth black. In this case 



