Jones: Inheritance of Silkiness in Fowls 



Table II. Malings in Which 3:1 Ratios Arc Expected 



127 



matings, but one (19) and here there is 

 an excess of silky feathered birds.^ 



The data given in Table II pertain 

 to those matings in which three nor- 

 mally, feathered birds are expected to 

 one silky. The types of matings are 

 similar to those described for Table I. 

 The numbers obtained for mating 21 

 are closer to expectation than for mat- 

 ings 22 or 24. There is also a deficiency 

 of recessives in this table. 



The p ' was determined for each 



■ mating and each group 



of matings. The formula used was that 



for Mendelian ratios of 1:1 and 3:1, 



namely P. E. = .6745- 



where 



p and q are the elements of the expected 

 ratio and n the total number of individ- 

 uals obtained in any one mating or 

 group of matings. The values are in 

 some cases a little high but in no 

 instance are they so large as to vitiate 

 the interpretation of the results. 



A further test of the genetic corre- 

 spondence of the plumages of the spor- 

 adic and purebred Silkies was made in 



■* The color of the Fi's of the sporadic silky- White Leghorn cross, as well as those from reciprocal 

 crosses of the purebred Silkies with White Leghorns, was white with splashes of black pigment. The 

 F2's were of various colors including blue, black, white, red, and white combined with varying amounts 

 of the other colors. 



another mating (No. 1 7) of an extracted 

 F2 sporadic silky by a purebred Silky. 

 Twenty silky feathered chicks were 

 obtained and no normally feathered 

 ones. 



The foregoing data, therefore, appear 

 to demonstrate conclusively that the 

 silkiness exhibited by sporadic silky 

 1 A is the same genetically as that of the 

 purebred Silky Fowl. 



DISCUSSION 



It is evident from the foregoing dis- 

 cussion that silkiness has occurred 

 sporadically in domesticated fowls for 

 a long time, very likely ever since their 

 domestication, and the character has 

 from time to time been combined with 

 various others to form different breeds 

 of Silkies. The evidence, so far as it 

 goes, would seem to indicate that it is 

 the same factor concerned in all cases. 

 It is not improbable that silky plumage 

 cropped out occasionally also in the 

 wild progenitors of the domestic fowl, 

 and for that matter it may still do so 

 in the wild Jungle Fowl, though no 

 mention of it has been noted. The fact, 



