SEROLOGY AND SYSTEMATICS 87 



For example, Makela has combined specificities and inhibitor charac- 

 teristics to distinguish two groups of genera as follows. Certain genera 

 produce agglutinin which act upon rabbit cells but not guinea pig 

 cells and are inhibited by certain sugars of group 2 (for example, 

 D-galactose). Most of them contain also anti-A + B or anti-B agglu- 

 tinins. Another group of genera produce agglutinins which act on 

 rabbit cells but also on guinea pig cells. These agglutinins are inhibited 

 by group 3 sugars (for example, D-glucose). Genera falling into the 

 former class are Bandeiraea, Sophora, Crotalaria, Cytisus, Caragana, 

 and Coronilla. Genera of the second group are Lathyrus, Lens, 

 Pisum, Vicia, and possibly Parkia. It is evident to taxonomists that 

 the two groups do not fall neatly into any systematic order. In fact, 

 the groups individually overlap even the sub-family level, and each 

 group includes a number of tribes, some of which are represented by 

 species in both groups. There is reason, however, in the opinion of the 

 writers, to expect the plant agglutinins to be systematically important, 

 if not at the tribal level then at least at the genus level. Since it has 

 been shown that the presence of at least one agglutinin is genetically 

 controlled, by that fact alone there is established a rational basis for 

 their distribution which is phylogenetic in principle. 



In the preceding chapter an example from zoological studies 

 and one from botanical studies were utilized to illustrate biochemical 

 systematics approaches which provided significant information but 

 which did not represent, entirely, correlations of the distribution of a 

 compound with a taxonomic system (for example, Vogel's investiga- 

 tion of lysine synthesis and Wald's investigation of the visual pig- 

 ments). Although it was not intended that this establish a precedent 

 for later chapters, in a general discussion of the possible role (includ- 

 ing the future role) of serology in phylogenetic studies it is useful to 

 review briefly one or two special applications of serology which, 

 although not directly relevant to systematics, nevertheless indicate 

 some of the possibilities of the method. In general, some of the limita- 

 tions of the gross quantitative serological method are obviated when 

 refined genetic stocks are available and appropriate preadsorption is 

 utilized. Since the genetic knowledge of the materials to be discussed 

 below is more complete than that of earlier studies, the implications 

 of the work seem to have greater validity. Again, one example is drawn 

 from plant studies and one from animal studies. 



The first example treats serological investigations of a series of 

 four pollen incompatibility alleles (S2, S3, S4, and Sq) of Oenothera 

 organensis carried out by Lewis (1952). Preadsorption was utihzed 

 not only to precipitate common protein antigens not connected with 

 the S-factors, but also to provide, artificially, what are referred to as 



