OBSERVATIONS ON SEROLOGY OF TUNA 



This paper describes observations and 

 experiments concerned with the serology of 

 tuna. The techniques and concepts used are 

 similar to those employed in blood type studies 

 (Cf. Mourant, A.E., 1954, Race, R.R., andR. 

 Sanger, 1954; and Owen, R.D., C.Stormont, 

 and M . R . Irwin, 1947). The antigens used in 

 blood-typing have certain properties that make 

 them peculiarly suited to comparative studies 

 of subpopulations (also often termed races or 

 breeding stocks) within single species. 



These properties may be briefly out- 

 lined as follows. First, the presence or ab- 

 sence of a particular antigen on the red blood 

 cells of an individual is genetically determined 

 in a direct manner, uncomplicated by domi 

 nance or gene interaction (excepting only very 

 rare instances). This means that the presence 

 of an antigen on a red blood cell is direct evi- 

 dence that the gene determining this antigen is 

 present in the individual involved, while the ab- 

 sence of this antigen on the cells of another 

 individual is direct evidence that the gene de- 

 termining the antigen is also absent In addition, 

 the direct relation between gene and antigen is 

 not influenced by variations in the environment 

 that the individual may be subject to during its 

 lifetime. 



These properties, together with the 

 highly sensitive yet relatively simple techniques 

 employed in blood-typing, make the red-cell 

 antigens particularly favorable indicators of 

 genetic variation within populations. Statistic- 

 al comparisons can therefore be made of the 

 frequency of occurrence of selected antigens 

 occurring among subpopulations . Such com- 

 parisons can reveal whether the subpopulations 

 are aliKe or different with respect to the fre- 

 quency of the antigens concerned, and therefore 

 whether they are freely interbreeding and ex- 

 changing genes. In this way separate breeding 

 stocks (races) may be detected through a study 

 of red-cell antigens when other meristic char- 

 acters are not available. 



The success of blood-type studies that 

 have been made on populations of humans, 

 cattle, doves, chickens, and other warm- 

 blooded animals led to the initiation of similar 

 studies on fishes (Cf. Gushing, 1952a, b; Gush- 

 ing and Sprague, 1952, 1953) with the aim of 

 extending this work to where it might be em- 

 ployed in the study of problems of interest to 

 fisheries . Of great interest in this connection 

 are studies by Japanese biologists (Yamaguchi 

 and Fujino, 1953; Fujino, 1953) who have been 

 able to discover variations in the blood types of 

 individuals within several species of whales, 

 and who have made a start in the antigenic 

 analysis of whale populations. 



The major objectives of the work re- 

 ported in the present paper have been to dis- 

 cover intraspecific individual variations in the 

 red-cell antigens of tuna, to investigate the 

 practicability of using samples of frozen whole 

 bloods, and to develop serological techniques 

 simple enough to be adapted to large-scale 

 field investigations of interest to fisheries re- 

 search and students of migration and evolution. 



Research was conducted at Santa 

 Barbara Gollege with the assistance of grants 

 from the Scripps Institution of Oceanography, 

 and for three weeks (in July 1955) at the Hawaii 

 Marine Laboratory, University of Hawaii, 

 Honolulu. The visit to Hawaii was made 

 possible by the Office of Naval Research, cur- 

 rently supporting in large part the author's 

 research through a contract for the investiga- 

 tion of the serology of marine animals. Work 

 with fresh intact tuna erythrocytes in Hawaii 

 led to the discovery of individual antigenic 

 variations in the oceanic skipjack and also per- 

 mitted a consolidation of the Santa Barbara 

 researches. George Durall is assisting in this 

 research. In addition, Mrs. Elyse Beaver and 

 former students Barbara DraKe, Lucian Sprague, 

 and Donald Shawhave contributed to various 

 phases of the work at Santa Barbara. 



