SHAKLEE ET AL.: BIOCHEMICAL GENETICS OF PACIFIC BLUE MARLIN 



(Sigma Chemical Co., St. Louis, Mo.) at a concen- 

 tration of 12% w/v. After electrophoretic separa- 

 tions, enzyme patterns were visualized using 

 standard histochemical staining recipes modi- 

 fied from Shaw and Prasad (1970), Selander et 

 al. (1971), and Siciliano and Shaw (1976). All 

 zymograms were photographically recorded. 



Patterns of enzyme variation which were con- 

 sistent with the subunit structure of the enzyme 

 (when known) and simple models of Mendelian 

 inheritance were scored and recorded as geno- 

 types. Names of enzymes and Enzyme Commis- 

 sion numbers follow the recommendations of the 

 Commission on Biochemical Nomenclature 

 ( 1973). For multilocus enzyme systems, loci were 

 given alphabetic designations when appropriate 

 (e.g., Gpi-A) or were simply assigned a number 

 beginning with 1 for the most anodally migrat- 

 ing isozyme. The most common allele at each 

 locus was designated 100, and all other alleles at 

 that locus were numbered according to their elec- 

 trophoretic mobility relative to the 100 allele. 

 Negative numbers refer to alleles with cathodal 

 migration. The putative genotype data were sum- 

 marized as genotype and allele frequency distri- 

 butions. The genotype distributions were exam- 

 ined for internal consistency with the Mendelian 

 inheritance model by chi-square testing of good- 

 ness-of-fit of observed genotype ratios with those 

 expected for a single random mating population 

 in the absence of differential selection among the 

 alleles. The expected ratios were computed from 

 observed allele frequencies using Levene's (1949) 



unbiased method for small samples. Heterozy- 

 gosity for each locus (h) was calculated as h = 

 1 -- XX i 2 where Xi is the frequency of the /th 

 allele. Average heterozygosity (H) was calculated 

 as the mean of h over all loci examined. 



RESULTS 



Tissue samples from 95 Pacific blue marlin 

 were analyzed. A total of 23 enzyme systems 

 representing 35 gene loci were satisfactorily re- 

 solved using extracts of muscle, liver, and eye 

 (Table 1). Heart and brain tissue did not add sig- 

 nificantly to this total. Eleven loci exhibited de- 

 tectable genetic variation in the sample of 95 

 fish analyzed. The enzymes adenosine deaminase 

 (Ada), mannosephosphate isomerase (Mpi), and 

 phosphoglucomutase (Pgm) all behaved as mono- 

 mers with two-banded heterozygotes. Aspartate 

 aminotransferase ( Aat-1), alcohol dehydrogenase 

 (Adh), glucosephosphate isomerase (Gpi-A), mus- 

 cle glycerol-3-phosphate dehydrogenase (G-3- 

 Pdh-2), liver isocitrate dehydrogenase (Idh-1), 

 phosphogluconate dehydrogenase (Pgdh), and 

 umbelliferyl esterase (Umb) behaved as dimers 

 exhibiting triple-banded heterozygous patterns. 

 L-iditol dehydrogenase (Iddh), often referred to 

 as sorbitol dehydrogenase in the literature, ap- 

 peared to be a tetramer as heterozygotes exhib- 

 ited a five-banded phenotype. 



Two of the 1 1 variable loci were represented by 

 only a single heterozygous individual out of the 

 95 fish screened. The remaining nine loci were 



TABLE 1.— Electrophoretic analysis of Makaira nigricans from Hawaii. M = muscle, 



E = eye, L = liver. 



Enzyme 



Loci 



Name (Enzyme Commission number) 



Abbr. 



Tissue 



Invariant 



Variable 



aspartate aminotransferase (2.6.1.1) 



adenosine deaminase (3.5.4.4) 



alcohol dehydrogenase (1.1.1.1) 



creatine kinase (2.7.3.2) 



enolase (4.2.1.11) 



esterase (3.1.1.—) 



glyceraldehy de-phosphate dehydrogenase 



(1.2.1.12) 

 glutamate dehydrogenase (1.4.1.2) 

 glucosephosphate isomerase (5.3.1.9) 

 glycerol-3-phosphate dehydrogenase (1.1.1.8) 

 hexose diphosphatase (3.1.3.11) 

 L-iditol dehydrogenase (1.1.1.14) 

 isocitrate dehydrogenase (1.1.1.42) 

 lactate dehydrogenase (1.1.1.27) 

 malate dehydrogenase (1 .1.1.37) 

 malate dehydrogenase (NADP*) (1.1.1.40) 

 mannosephosphate isomerase (5 3.1.8) 

 peptidase (3.4.11 . — ) 



phosphogluconate dehydrogenase (1.1.1.44) 

 phosphoglucomutase (2.7.5.1) 

 superoxide dismutase (1.15.1.1) 

 umbelliferyl esterase 

 xanthine dehydrogenase (1.2.1.37) 



87 



