PREPOTENCY (Lat. preepotentia, superior power, from to be superior in power, from pro•, before -)- posse. to be able). The power of exerting a preponderating influence in the net of reproduction. Thus some one male an cestor excelling in some physical or mental char acter, such as form. color, and disposition, is known to have transmitted his qualities through many generations. Not only may the individuals of a normal species thus transmit their marked or superior qualities, hut also aberrations or `sports' may thus be transmitted, unless bred out by crossing. In certain historic families some one ancestor, and after him others in the same family have shown great power in transmitting their likeness through the male line, as in the ease of the Austrian emperors of the House of Hapsburg, and so with the mental qualities of certain Boman families. It is especially notice able among domesticated animals, where qual ities and ancestry have long been recorded. The famous bull 'Favorite' is said to have exerted a prepotent inlImence on the short-horned race of cattle. A ram of a goat-like breed of sheep from the Cape of Good Hope had offspring scarcely distinguishable from himself when crossed with ewes of twelve other breeds. Other cases are mentioned by Darwin. Darwin says that the law of prepoteney acts when species as well as when races or individuals are crossed, giving examples among plants. The jackal is prepotent over the dog, the ass over the horse, and this runs more strongly through the male than the female ass.
The intricacy of prepoteney is reiterated by liwart, and is likely to be difficult to understand until the laws of heredity are better understood. He says the leader of any given wild herd may be decidedly prepotent, but sinless he is mated with members of some other herd presenting dif ferent characters the prepoteney may escape no tice. The Jews are more prepotent than the Eng lish race, are of better, i.e., purer breed, but the prepoteney only declares itself when intermar riages take place. In nature prepoteney nay (1) arise spontaneously and abruptly along with sports in one or more directions. or gradually with the help of natural selections; (2) it may be gradually acquired when a few individuals of any given species or variety are so isolated that inbreeding is inevitable. In eases of crosses be tween different breeds, says Redfield, prepoteney appears to lie with that breed which has had its characters most firmly fixed by in-and-in breed ing. Hence animals of pure blood are prepotent over mongrel stock. In the life of an imlividual a character is more firmly fixed in middle life than in youth, and observation has shown among horses that the older individual is or tends to he more prepotent than young, males.
Consult: Darwin, The Variations of Animals and. Plants Under Domestication (London, 1888) ; Ewa rt, The Penyruik Experiments (London, 1899).