scribed in Aebersold et al. (1987). Buffer systems 

 included the following: 1) a Tris-boric acid, EDTA 

 system (pH 8.5) (Boyer et al. 1963); 2) an amine 

 (3-aminopropyl morpholine) citrate system (pH 6.5) 

 (Clayton and Tretiak 1972); and 3) a discontinuous 

 Tris-citric acid (gel pH 8.15), lithium hydroxide, boric 

 acid (electrode pH 8.0) system (Ridgway et al. 1970). 

 Methods for visualizing enzyme activity followed 

 Siciliano and Shaw (1976) and Harris and Hopkin- 

 son (1976). A system of nomenclature suggested by 

 Allendorf and Utter (1979) was used to designate 

 loci and alleles. 



The 25 polymorphic loci (Table 2) were selected 

 from a larger set of loci known to be variable in 

 Chinook salmon. Variable loci were excluded when 

 data were unavailable for one or more of the sam- 

 pling locations listed in Table 1. Much of the de- 

 scriptive data for the loci and alleles were previ- 

 ously reported (Utter et al. 1980; Milner et al. fn. 

 4). Two previously unreported polymorphic en- 

 zymes in Chinook salmon, Gr and Gpi-l(H), were 



used for population studies and are described in the 

 appendix. 



Allele frequencies were calculated directly from 

 phenotypic classes for 14 nonduplicated loci. Tests 

 for departures of genotypes from the expected 

 binomial distribution (Hardy-Weinberg equilibrium) 

 were made using a G statistic (Sokal and Rohlf 1969) 

 with degrees of freedom equaling the number of ex- 

 pected genotypes minus the number of alleles. The 

 isoloci Aat-1,2; Idh-3,4; Mdh-1,2; Mdh-3,4; and Pgm- 

 1,2 (see Allendorf and Thorgaard 1984) were ex- 

 cluded from such tests because every individual was 

 scored on the basis of four allelic doses from two 

 loci. Combined allele frequencies of both loci were 

 calculated directly from phenotypic expressions and 

 were assumed to be the same at both loci for statis- 

 tical calculations. The data for the Gpi-2 locus and 

 the Gpi-l(H) allele were also excluded from Hardy- 

 Weinberg calculations because common homo- 

 zygotes and heterozygotes could not be reliably 

 distinguished, and allele frequency estimates were 



Table 2.— Background information on Chinook salmon tissue samples for protein coding loci. 



Buffer Refer- 



Protein name and enzyme number Locus Tissue' system ence^ 



Aconitate hydratase (4.2.1.3) 

 Adenosine deaminase (3.5.4.4) 

 Aspartate aminotransferase (2.6.1.1) 



Dipeptidase (3.4.13.11) 



Glucose-6-phosphate isomerase (5 3 19) 



Glutathione reductase (16.4.2) 

 Isocitrate dehydrogenase (1.1.1.42) 

 Lactate dehydrogenase (1.1.1.27) 



Malate dehydrogenase (1.1.1 .37) 



ru1annose-6-phosphate isomerase (5.3.1.8) 

 Phosphoglucomutase (2.7.5.1) 

 Phosphoglycerate kinase (2.7.2.3) 

 Superoxide dismutase (1.15.1.1) 

 Tripeptide aminopeptidase (3.4.11.4) 



21 



liver, E = eye, H = heart. M = muscle. 



Milner et al 1983. 2 = variation described in this study 



242 



