ATLANTIC REDFISH 



353 



Table 3. — Resultx of absorbing rabbit anti-cod scniin 

 (MIC8R) witli erythrocytes of six indiridual Eastport 

 redfish 



others, while absorption with cells of fish Nos. 2, 

 3, 5, and 6 removed antibodies for each otlier but 

 left antibodies which agglutinated cells of tish 

 Nos. 1 and 4. These reactions were reciprocals of 

 those obtained by absorbing the anti-redfish 

 (GBR17II) serum. They immediately suggested 

 that the anti-cod (MIC8R) was principally an 

 anti-As sermn, while the anti-redfish (GBKITR) 

 was principally an anti-Ai serum. Therefore, by 

 absorbing the MIC8R antiserum with Aj cells 

 (No. 2, 3, 5, and 6, and others with similar re- 

 action), a reagent was obtained which reacted 

 only with A^ cells. This provided two reagents, 

 one (prepared p^e^-iously by absorbing GBR17R 

 antiserum with A. cells) which agglutinated only 

 cells with A] antigen; the other (prepared by ab- 

 sorbing MIC8R antiserum with Ai cells) which 

 agglutinated only cells with A; antigen. It was 

 then possible to definitely identify fish as possess- 

 ing either antigen Ai or Ao. 



Since the original stock of jNIICSR antiseinim 

 was small, other specific anti-redfish sera were 

 jiiepared. Rabbits were immunized with cells of 

 indi\-idual redfish pi-eviously tested for A antigens. 

 Two antisera (GBR31R 'and GBR32R) were 



especially useful in preparation of specific A, re- 

 agents. Results of absorptions of GBR31R anti- 

 serum are illustrated in table 4. More than 75 

 percent of redfish sampled thus far from the East- 

 port (Maine) population possessed antigen Ai. 

 Future work logically involves testing large num- 

 bers of individuals from each major fishing 

 area to determine whether variations in antigen 

 frequencies exist. If such variations occur, the 

 maximum amount of intermixing could be 

 determined. 



DISCUSSION 



Blood-group antigens of the kind considered 

 in this paper have been most thoroughh- studied 

 ill mannnals and birds. Blood-group systems 

 liave l)een proposed for humans, cattle, whales, 

 chickens, and certain other animals. Wher- 

 ever studied, the erj-throcyte antigens com- 

 posing these systems have been found to be 

 genetically determined, with relatively simple 

 inheritance usually involving a single locus. 

 Comparable studies of fishes are still in their in- 

 fancy, but should be as useful to studies of fish 

 populations and migrations as human blood 

 groups are to anthropological studies, or as blood 

 groups of cattle are to herd-lineage problems. 

 Information derived is genetic, and may pi-ovide 

 a more adequate picture of the population struc- 

 ture of a species than is possible with morphologi- 

 cal criteria, many of which are subject to modifi- 

 cation by environmental factors. 



From research in this laboratory (Sindermann 

 and flairs, 1950) and that reported from else- 

 where (Gushing, 1956; Ridgway. Gushing, and 

 Durall, 1958 ; Suzuki, Shimizu, and Morio, 1958 ; 

 and others) , it is already apparent that individual 

 variations in en'throcvte antigens characterize 



Table 4. — Results of absorbing rabbit anti-redfish (anti A,) serum (GBR31R) with cells of 12 Eastport {Maine) redfish 



