lO 



The Journal of Heredity 



RIGHT EAR OF GAMBOGE 



Quite often the development of the notch is 

 other, but the larger notch occurs just as often 

 The notch in the left ear is slightly larger in this 



be normal. At the time of examina- 

 tion the sex of twenty-seven of these 

 offspring was noted, and fourteen 

 females and three males were recorded 

 among those with notched ears, and 

 nine females and one male among those 

 with normal ears. The excess of fe- 

 males is due to the fact that the bulls 

 had been disposed of as soon as 

 weaned, but most of the heifers had 

 been retained, thus making more 

 females available for examination. Had 

 the character been a simple sex-linked 

 recessive, it would not have shown in 

 any of the offspring, while if it had been 

 a simple sex-linked dominant it would 

 have shown in all of the daughters but 

 none of the sons. 



Two calves sired by unrelated bulls, 

 out of daughters of Gamboge's Raleigh, 

 were examined. Both calves had nor- 

 mal ears. The mother of one of them 

 had normal ears and the mother of the 

 other had ears almost or quite as 

 deeply notched as those of Gamboge's 

 Raleigh, himself. 



A SINGLE DOMINANT FACTOR 



The only tenable hypothesis seems to 

 be that the notched ear is due to a single 



S RALEIGH 



greater in one ear than in the 

 in the right ear as in the left, 

 animal. (Fig. 6.) 



dominant 

 factor inde- 

 pendent of 

 sex. If Gam- 

 boge's Raleigh 

 is heterozy- 

 gous for this 

 factor, his 

 calves should 

 be equally 

 divided be- 

 tween those 

 with notched 

 and those 

 w i t h u n- 

 notched ears. 

 The actual 

 results of 12 

 normal and 18 

 notched, de- 

 viate only 

 three from 

 expectation. 

 Since the 

 probable er- 

 ror is 1 .8, this 

 deviation cannot be regarded as signifi- 

 cant. The normal daughter produced a 

 normal calf as expected, and the notched 

 daughter, that should produce normal 

 and notched calves in equal numbers, 

 has thus far produced one normal calf. 

 Further proof of this simple hypothesis 

 waits upon the production of more 

 calves by Gamboge's Raleigh and more 

 calves from his daughters with the 

 notched ears. Since he is a good 

 individual and his daughters are excel- 

 lent producers, it may be possible to 

 inbreed or linebreed to him to secure 

 animals homozygous for this factor, 

 but since the notched ear has little 

 economic importance in itself, it is not 

 likely that any expensive plan centered 

 on securing and demonstrating such 

 homozygous individuals will be under- 

 taken. 



The degree of expression of the 

 factor varies in different animals. The 

 deeper notches are always accompanied 

 by the doubling of the sharp projection 

 but the shallower notches do not have 

 this and in some cases the notch is 

 barely more than a straight line cutting 

 off a normally curved portion of the 

 ear. Neither is the notch always 



