66 



The Journal of Heredity 



ONE OF THE RED LAMBS SIRED BY PULTAVA 



His dam was a black first generation hybrid ewe, like the lambs shown in fig. 8. Had his sire 

 been a pure Karakul he would have been black, and a valuable animal from the breeder's pomt 

 of view. The relationship of these color factors is of great practical importance in producing 

 high grade fur sheep. (Fig. 9.) 



desired density, luster and curl, and 

 half of the gametes will be totally 

 lacking in this factor (b). 



It is evident Pultava could not have 

 been homozygous for the black factor 

 (B), because he produced many red, 

 spotted, and white lambs. Assuming 

 then that Pultava had to be heterozy- 

 gous for the black color factor (B) he 

 could have had any one of the following 

 heterozygotic forms with respect to 

 color factor red (R): 1. (BbRR) 2. 

 (Bbrr) 3. (BbRr). Running through 

 the series of possible heterozygotic 

 forms for the Fi ewes, mating from this 

 assumption would have resulted as 

 shown in Table I. 



Of the three possible forms listed in 



Table I it is apparent Pultava could 

 only have been of the form (BbRr). 

 The theoretical possibilities are very 

 close to the actual obtained results; as 

 is shown in Table II. 



It must be remembered, however, 

 that twenty-five percent of the Fi 

 black ewes have a possible heterozygous 

 constitution of (BbRr) ; crossing these 

 gametes gives results as shown in Table 

 III. 



Again the theoretical possibilities 

 check close enough with the obtained 

 results to make the (BbRr) assumption 

 entirely probable; as is shown in Table 

 IV; the apparent difference of 33 to 28 

 and 1 1 to 25 is not significant when it is 

 remembered that the average ratio of 



