JOHNSON, UTTER, and HODGINS: ELECTROPHORETIC COMPARISON OF SHRIMPS 



Origin 



Species: P hypsmolus P gomufus Pboreaiis Pdispor P jordoni 



Figure 3. — DiagT^ammatical representation of the alleles of 

 phosphoglucomutase in five species of pandalid shrimps as 

 shown by the technique of starch-gel electrophoresis. 



from expected Hardy-Weinberg values, and the 

 gene frequencies of intraspecific samples were 

 similar over the geographic range samples for 

 P. jordani. 



The collections of P. hypsinotus from Alaska 

 showed highly significant deviation from Hardy- 

 Weinberg expectations. Variation from expected 

 Hardy-Weinberg proportions has also been ob- 

 served for PGM variants of Pacific ocean perch, 

 Sebastes alutus (Johnson et al., 1971) and related 

 to depth of capture. Gene frequencies were similar 

 for shallow- and deepwater collections; however, 

 deepwater collections deviated significantly from 

 expected Hardy-Weinberg frequencies. Further 



sampling stratified by depth (or other measurable 

 variables) may reveal similar relationships for 

 PGM variants of P. hypsinotus. 



Inspection of the allele frequencies of the 

 Alaskan and Washington collections of P. hyp- 

 sinotus showed marked differences, especially 

 with the A and E alleles (Table 1). These 

 differences indicate that PGM variation may be 

 useful in population identification of P. hypsino- 

 tus. Bullini and Coluzzi (1972) have presented 

 evidence for selection of PGM alleles over a broad 

 geographic range in mosquitoes Aedes aegypti 

 and A. marine. Additional sampling of P. hyp- 

 sinotus may reveal a similar phenomenon as that 

 found in the mosquito species. 



The general protein, LDH, and PGM patterns 

 observed in the five species were used to produce 

 a key by which the species can be separated 

 (Figure 4). This type of key should prove useful 

 in application to shrimp identification problems. 



CONCLUSION 



The general protein patterns separated the 

 species examined into two groups, one consisting 

 only of P. hypsinotus and the other containing 

 the remaining species of Pandalus and Pan- 

 dalopsis dispar. 



All five species of shrimp studied were poly- 

 morphic for PGM, with Pandalus hypsinotus 

 possessing the greatest number of alleles (four 



Table 1. — Phosphoglucomutase phenotypes of Pandalus hypsinotus taken off Alaska and Washington, 1971-72.' 



Phenotypes of PGM 



Mn parentheses are the expected values of a Hardy-Weinberg distribution. 

 ^Chi-square test of Hardy-Weinberg distribution. 



801 



