252 



M. R. IRWIN 



These results illustrate the observation that an individual has any cellular 

 character recognized to date only if one or both parents possessed it. Also, 

 each behaved as if it were a dominant to its absence. 



From further isoimmunizations in cattle, and from immunizations of rab- 

 bits, various antisera have been obtained which detect other antigenic factors 

 of cattle cells. Each of these has been subjected to the criteria of both genetics 

 and immunology for a single character, as described in reports by Ferguson 

 (1941), Ferguson et al. (1942), and Stormont (1950). At present, about forty 

 different reagents are regularly used in typing cattle cells. 



Other Antigens in Cattle 



As stated above, the first substance detected in cattle cells was named A. 

 The next was called B, the next C, . . . Z. That called A' implies no relation- 

 ship to A, nor B' to B, etc. Each of these antigenic factors is therefore recog- 

 nized independently, and when subjected to an analysis of gene frequency, 

 each has behaved as expected if effected by a single gene in comparison to its 

 absence. 



However, some definite associations have been noted among them. For 

 example, Ferguson (1941) reported that the C and E factors were not inde- 

 pendent, for only C occurred alone, whereas E was present always with C, 

 and such cells therefore had CE. It was postulated that there were three al- 

 lelic genes involved, one for the components C and E together, one for C 

 alone, and a third for the absence of both C and E. 



It was later noted by Stormont that certain additional antigenic factors 

 appeared only if one or more other components also were present. For ex- 

 ample, the substance B occurs alone, as does that called G. But a third factor 

 called K has never been observed unless both B and G were also present. 

 (A possible exception to this rule was noted shortly after these factors were 

 first demonstrable, and a weak reaction at that test with the reagent for the 

 G substance was probably incorrectly recorded.) This association of K with 

 B and G has been noted in over eighteen hundred animals of more than six 

 thousand tested. Hence the combination of the BGK factors has always oc- 

 curred as a unit, and it has also behaved as a unit in the progeny of individ- 

 uals possessing it. A compilation of some unpublished data has yielded the 

 following information: 



