CHAPTER X 



OTHER KINDS OF HYBRIDIZING 

 Blended Inheritance 



WE have seen in the cases that come under Mendel's law that 

 the contrasted characters do not both develop at the same time, the 

 offspring in the first generation being often like one or the other 

 parent. Yet in some of these cases there is evidence that the 

 dominant character may be weakened by the recessive one. We 

 may now consider cases in which the contrasted characters of 

 the two parents fuse or blend completely in the offspring. Cases 

 of the sort are found not only between races, varieties, and elemen- 

 tary species, but this method of union has long been supposed to 

 be a characteristic feature of hybridization when Linnaean species 

 are crossed. 



The most familiar and striking case of fusion or blending of 

 two characters is found in the mulatto the result of union of a 

 white and a black individual. The mulatto breeds true in all 

 successive generations, neither the white nor the negro ever 

 appearing again in the pure form. If the mulatto again crosses 

 with the white stock, the dark color is again lessened, but even 

 after several generations of crossing with the white stock traces 

 of the dark pigment remain. Conversely crosses between the 

 mulatto and the black race produce ever increasing shades 

 of darkness in successive generations of offspring. Not only 

 the color, but the character of the hair also shows a tendency 

 to blend in the hybrid. 



Flourens made crosses between the domestic dog and jackal, 

 the latter being, however, "prepotent." The horse and the ass 

 give the mule, that is intermediate in many respects, but the 



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