64 



Fishery Bulletin 88(1), 1990 



Figure 1 



Species-specific fragment patterns of nitDNA isolated 

 from three species of P(iralahrn,r and digested with the 

 restriction endonucJeaseZ/iHrflll. Note that the upper 

 (larger) bands distinguish the three species. From left 

 to right: P. ctathratu.-i (1). P. niaculatofasriatus (2). 

 P. nebulifer (2), and the size standard (BRL 1 Kb 

 ladder). The mtDNA restriction fragments were 

 endlabeled with radioactive nucleotide triphosphates, 

 separated on a 1.0% agarose gel and visualized by 

 autoardiography. 



Figure 2 



A Southern blot of //i»i/ III digests of genomic ONA isolated from 

 individual Paralabrax eggs and probed with biotinylated Paralahrax 

 mtDNA. The eggs can easily be identified on the basis of the frag- 

 ment patterns by comparison with those in Figure 1. One prepara- 

 tion (lane .5) did not contain sufficient DNA for identification. From 

 left to right: P. maculatofasciatus (2), P. nebidifer (2), and P. cUi- 



because there was not sufficient mtDNA fcir visual- 

 ization of the restriction fragments. However, samples 

 as small as 0.6 mg(one Pdntlahrax egg) could be iden- 

 tified after Southern transfer and hybridization with 

 a biotinylated probe (Fig. 2). Although greater sensi- 

 tivity could have been obtained with a radioactively 

 labeled probe, the results obtained with the biotinylated 

 probe were sufficient to identify an individual fresh or 

 ethanol preserved egg, and avoided the cost and prob- 

 lems of probe half-life and waste disposal associated 

 with radioactively labeled probes. 



