Little Wenatchee River which are the 

 major spawning areas for Columbia River 

 sockeye salmon. Since these two popu- 

 lations were examined at a later date and 

 under somewhat different conditions, it 

 is necessary to assign the individual fish 

 to the three categories on the basis of the 

 modes present in the population, rather 

 than according to standard score values. 

 For this reason, the present analysis must 

 only be considered as a guide toward further 

 studies under more refined conditions. 



It is of interest that the Mendelian 

 populations taken from spawning grounds 

 gave data that appear to fit the Hardy- 

 Weinberg equation quite well, while two 

 out of three populations that were known 

 to be mixtures of breeding stocks did not, 

 nor did a composite of all populations 

 (Table 3)- In the two cases where the 

 number of fish was sufficient in all cate- 

 gories for the application of the Chi 

 Square test these conclusions appear to be 

 statistically sound. (Okanogan River X = 

 0.106 d.f. = 2, "composite population" 

 X = 61. 9 d.f. = 2). 



Although the close agreement of the 

 actual Bristol Bay data with the Hardy-. 

 Weinberg Law may possibly be due to chance 

 alone, the results may tentatively be 

 ascribed to the several populations in this 

 system being genetically homogeneous with 

 respect to the relative frequencies of "A" 

 and "a". While the reasons for and impli- 

 cations of this homogeneity remain to be 

 determined, three not mutually exclusive 

 possibilities suggest themselves. The 

 first is that the various "parent -stream" 

 stocks, while genetically isolated, have 

 not diverged with respect to the frequen- 

 cies of these genes as they obtained in a 

 common ancestral stock. The second is 

 that the various "parent-stream" stocks 

 are not sufficiently isolated to allow for 

 divergence of the frequencies of the two 

 alleles among them. The third is that 

 identical selection pressure in the 

 separate populations may impose identical 

 points of genetic equilibrium. 



The failure of the Columbia River 

 and Pacific Coast samples to conform to 

 the Hardy -Weinberg formula can be ex- 

 plained by the fact that each represents 

 a mixture of populations differing with 

 respect to the frequencies of A and a. 

 This explanation receives support from 



consideration of the good fit of samples 

 obtained on the spawning grounds of the 

 upper Columbia after the Wenatchee and 

 Okanogan runs had separated from each 

 other. In these cases, where fairly large 

 samples were taken from known Mendelian 

 populations, the distribution of scores 

 does conform to the Hardy-Weinberg law. 

 In view of these various considerations 

 there seems to be good reason to postulate 

 that the variations in erythrocyte antigens 

 which we are comparing are genetically 

 controlled by a simple allelic system of 

 genes, the frequencies of which may vary 

 in racial stocks of different geographic 

 origins . 



ACKNOWLEDGEMENTS 



The authors wish to express their 

 sincere appreciation to the faculty of the 

 Department of Microbiology, University of 

 Washington for making laboratory space 

 available for this investigation; to the 

 many fishery biologists who assisted with 

 the sample collections; to the Biometrics 

 Unit, Pacific Salmon Investigations for 

 performing the analysis of variance; to 

 Dr. Lucian Sprague for several of the 

 animal serums; and to Mr. G. W. Klontz for 

 technical assistance with some of the 

 experiments. 



SUMMARY 



1. In over 700 cross matches between the 

 cells and serums of samples from 

 several localities, no evidence was 

 obtained for the existence of natural 

 isoagglutinins in sockeye salmon. 



2. The normal serums of several humans, 

 cattle, horses, sheep, pigs, goats 

 and brown bullheads were tested for 

 agglutinative activity with the 

 erythrocytes of sockeye salmon. Only 

 horse serum and pig serum reacted 

 strongly with the salmon cells. 



3. Consistent differences were found in 

 the strength of reaction of some pig 

 serums with the cells of individual 

 sockeye salmon. 



The frequencies of the various strengths 

 of reaction, which were expressed as 

 scores, were found to differ significantly 



