Q. Dark Sebright nearer to hen C (1). Thoroughly stippled with game tail. Neck and breast dark Sebright. Probably a new class nearer to (C).
R. Two cocks. Pale yellow instead of reddish, and much less black than are other yellows. No class of hens to match.[2]
In regard to color inheritance the preceding 19 birds are too few to add anything of significance to the other results, except that they serve to emphasize the dominance of the factors making for Sebright coloration. The hen-feathered cocks confirm the other results as to the dominance of the factor or factors in question.
There can be little doubt that some of these classes are complex. They almost merge into each other and in one part of the body individuals may grade off into one class, in other parts into other classes. An almost continuous series of types might be arranged from black to pale yellow.
The difficulty of matching the hen-feathered males to their genetic mates is almost insuperable. In table 1 an attempt was made to put these males with their respective females. The difficulty is, of course, greater for the cock-feathered birds, even with the castration evidence (that is too meager at present for the purpose), but a few of the males may be placed with certainty, and the rest guessed at.
One bird appears to be a hen-feathered game male resembling in many respects the female game, but darker and redder. There is more shafting on cape and wing-bow. The breast is unusually dark-salmon. The hackle is darker than is the game female. Upper wing-coverts broadly laced with black. (Plate 10, fig. 3.)
The occurrence of this hen-feathered jungle-fowl is so unique and the coloration of the bird so interesting that I have added to the plates three feathers of such a bird, viz., a stippled saddle feather, a feather from the back, a hackle feather, and a wing covert with stippled center and a black border. The neck hackle departs somewhat from the hackle of the jungle-fowl hen, but in the same direction as does the neck hackle of the Sebright cock from his hen.
Looking over the F₂ group, the most noticeable thing is the large number of blacks (E and G), all of which are stippled. Probably the factor came from the game, because group E was present in the back-cross as well as in F₂, and because these black birds are always stippled. The yellow color (I and J) may have come from both, each breed having then a black factor that, as a pattern, covers over most of the yellow. It is difficult to distinguish penciling from stippling in the F₂ yellows. Without figuring each of these types, their description in detail is not of much value. The skins will be deposited for reference in the Zoological Laboratory of Columbia University.
C. Back-Cross of F₁ to Game.
As the back-cross of the F₁ to the game might appear more likely to reveal the kinds of germ-cells present in the individual, the results from such a cross may be given before discussing the genetic data. If it were certain that the “game” contained all of the recessive factors that are involved in the experiment, this method of testing the result would be ideal, but there is no way of determining a priori whether this is the case. The question will be taken up later. The presence of two kinds of males with corresponding but largely uncorrelated differences in their plumage makes their classification as a group impossible. It is simpler, therefore, to put the females into their classes first, after which the hen-feathered males may be expected to fall into the same groups (or nearly so), while the identity of the cock-feathered males, i. e., their class relationship can only be determined for the classes that resemble the F₁ and the P₁ birds. The F₂ hen-feathered males can in part be further identified by means of the evidence that castration of these types affords.