442 



SCIENCE. 



[N. S. Vol. XXIV. No. 614, 



Litter No. 1 — 3 wild boar's color. 



1 Tamworth red. 

 Litter No. 2 — 1 wild boar's color. 



3 Tamworth reds. 

 Litter No. 3 — 2 wild boar's color. 



2 Tamworth reds. 



The sum of these results agree exactly with 

 the highest Mendelian expectation if we as- 

 sume the two coat colors to constitute a char- 

 acter pair, the color of the wild boar being 

 dominant, 



A cross between a Tamworth boar and a 

 Yorkshire sow resulted in eleven pigs, all 

 alike: hair entirely white; skin dark with 

 white spots, but with a white belt extending 

 entirely around the body at the shoulders, and 

 including the fore legs; face dished like the 

 Yorkshire but with long snout of the Tam- 

 worth. One of these hybrids (male) was 

 crossed with a Tamworth colored three fourths 

 Tamworth, one fourth Yorkshire, with the fol- 

 lowing interesting result: 



Eepresenting the body color of the Tam- 

 worth by R (r when latent), and that of the 

 white breed by W, the Mendelian formula for 

 this complex breeding would be 



B 

 W 



B 

 Wr 



the R^ being the three fourths Tamworth, one 

 fourth Yorkshire dam, the Wr^ being the hy- 

 brid Tamworth- Yorkshire sire. To agree 

 with this formula, half the progeny should be 

 white (dominant hybrid) and half red (ex- 

 tracted recessive). There were eight pigs in 

 the litter, four of which were of a rich Tam- 

 worth red color, and four with hair light gray 

 tinged with red, white skin with dark patches, 

 and the characteristic white belt of the orig- 

 inal hybrids. These results indicate that the 

 red and white coats of these breeds form a 

 character pair, with white dominant, as it is 

 in the Yorkshire-Berkshire and the Yorkshire- 

 Poland China crosses (unpublished results of 

 the writer). They also indicate that the dom- 

 inant hybrid (Wr) shows traces of recessive 

 characters present, as all the Wr progeny thus 



far produced show the peculiar white belt of 

 skin color around the body, and (in all but 

 the original Wr litter) have a reddish tinge in 

 the hair color. 



The same Wr male was bred to a Poland 

 China sow (black with white points), the 

 formula for which breeding (assuming red 

 dominant over black) would be 



Wr ^ r ^Wb 

 B j XiBb 



This calls for half the progeny white and 

 half red. The actual results were four white 

 or black and white, and five red or black and 

 red. In each case the recessive black ap- 

 peared to a greater or less extent. Of the 

 four, two were pure white with dark skin, 

 one was black and white spotted, and one was 

 black with white points, like a pure Poland 

 China. In Yorkshire-Berkshire crosses I 

 have found the usually recessive black appear- 

 ing conspicuously in some Wh individuals, 

 so that these results are explained by as- 

 suming incomplete dominance of white. Of 

 the five showing red color, three were nearly 

 pure Tamworth red, having only a few black 

 spots, and two were red and black spotted. 

 This indicates a tendency for red to dominate 

 black, but the dominance varies, and is almost 

 never complete. 



One of the above red- and black-spotted 

 boars was bred to three Poland China sows. 

 The formula for this breeding may be written 



B ) 



VWry ( \Wb 



J5 j 1 IBB -| r iBB 



B ] \lB 



Remembering that the Poland China black 

 appears either as black and white spotted or 

 black with white points in pure Poland 

 Chinas, we should expect half of each litter 

 to be red and black spotted and half black 

 and white spotted (or black with white 

 points). The results were 



Bl and Wh. 

 BR Spotted. Spotted. 



Litter No. 1 4 4 



Litter No. 2 3 3 



Litter No. 3 3 3 



