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Montana Conservation Genetics Laboratory 



Division of Biological Sciences * University of Montana * Missoula, MT 59812 

 (406)243-5503/6749 Fax (406)243-4184 



October 10, 2005 



Ladd Knotek " " 



Montana Department of Fish, Wildlife, and Parks 



3201 Spurgin 



Missoula, Montana 59801 ' ^ 



Ladd; , 



Following is my assessment of the high priority samples you wanted checked for t. 

 accuracy of data interpretation: , ■, 



Union Creek (#2047) 



This sample collected June 5, 2000 was originally reported as appearing to have come 

 from a hybrid swarm containing about a 92% westslope cutthroat and an 8% rainbow 

 trout genetic contribution. This does not really appear to be the case, but from a 

 management perspective the discrepancy in interpretation is moot. 



There appeared to be some problem with obtaining DNA from the samples and/or in the 

 polymerase chain reaction (PCR) used to copy the DNA as data are really available from 

 only four of the six diagnostic loci that we normally analyze that usually distinguish 

 rainbow trout from westslope cutthroat trout. PINE fragments characteristic of rainbow 

 trout were detected at three of the four diagnostic loci from which data were obtainable. 

 The rainbow trout fragments, however, do not appear to be randomly distributed among 

 the fish in the sample (Poisson distribution; Chi-square, P<0.05). In contrast, 

 significantly more fish than expected by chance (N=15) possessed markers characteristic 

 of only westslope cutthroat trout at all loci analyzed and significantly more fish (1) 

 possessed markers characteristic of rainbow trout at three of the diagnostic loci analyzed. 

 Furthermore, significantly fewer individuals than expected by chance (4) possessed a 

 rainbow trout marker at only one diagnosfic locus. This nonrandom distribution of 

 rainbow trout markers among the fish in the sample at the diagnostic loci suggests that at 

 the time of sampling the population contained a mixture of non-hybridized westslope 

 cutthroat trout and hybrid individuals between westslope cutthroat and rainbow trout. In 

 this situation, conclusively determining which individuals are non-hybridized will be 



