„o->MVi 



University 

 of Montana 



Department <ii /.oolo}-.> • Missoula, Montana >')XI2 • (4(td) 2-13-5122 



August 27, 1984 

 Mr. Bruce Rehwinkel 

 Box 251 

 Whitehall, MT 59759 



Dear Bruce: 



We have completed the electrophoretic analysis of the Salmo sample you 

 collected from German Gulch Creek (N=39, S 26, T 3N, R 10W) on 27 July 1984. 

 We examined the protein products of 45 loci in all the fish (Table 1). Thirteen of 

 these loci can be used to differentiate westslope cutthroat (S. clarki lewisi), 

 Yellowstone cutthroat (S. c. bouvieri), and rainbow trout (S. gairdneri ) 

 (Table 2). There is no evidence of rainbow or Yellowstone cutthroat trout 

 genetic material in the sample at any of these loci. With this sample size, 

 we would detect even as little as one percent rainbow or Yellowstone genes 

 in the population over 99 percent of the time. Thus, this is almost certainly 

 a genetically 'pure' population of westslope cutthroat trout. 



There is evidence of genetic variation at seven of the loci examined 

 (Table 3). We have detected the Idh3(71) allele only at low frequencies 

 (i.e. less than 0.10) in a few other populations of westslope cutthroat trout. 

 This allele, however, is present in the German Gulch Creek westslope cutthroat 

 trout at a very high frequency (0.974). This indicates that this population 

 is genetically distinct from the other populations that we have examined, and 

 thus, represents an extremely valuable resource. 



We have not detected many pure populations of westslope cutthroat trout 

 among the numerous samples that we have analyzed from western Montana. Most 

 populations suspected to be pure westslope cutthroat trout also contain 

 rainbow or Yellowstone cutthroat trout genetic material. The available data 

 indicate that the westslope cutthroat is in danger of extinction. In order 

 to ensure the continued existence of this native species, it is important 

 to preserve all pure populations that are identified. 



Sincerely, 



r 



X4& f rjUu 



Robb F. Leary 

 Genetics Laboratory 



/ 



(JW.ft 



Fred W. Allendorf 

 Professor 



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RFL/pkf 

 Enclosures 



Equal Opportunity in Education and Employment 



