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View Full Version : Return of a giant: DNA from archival museum samples helps to ID cutthroat



salmonid
12-08-2017, 12:04 PM
Cool recent research from University of Nevada, Reno.

Currently one small, native population of the culturally and ecologically important Lahontan cutthroat trout (Oncorhynchus clarkii henshawi, LCT, Federally listed) remains in the Truckee River watershed of northwestern Nevada and northeastern California. The majority of populations in this watershed were extirpated in the 1940s due to invasive species, overharvest, anthropogenic water consumption and changing precipitation regimes. In 1977, a population of cutthroat trout discovered in the Pilot Peak Mountains in the Bonneville basin of Utah, was putatively identified as the extirpated LCT lacustrine lineage native to Pyramid Lake in the Truckee River basin based on morphological and meristic characters. Our phylogenetic and Bayesian genotype clustering analyses of museum specimens collected from the large lakes (18721913) and contemporary samples collected from populations throughout the extant range provide evidence in support of a genetically distinct Truckee River basin origin for this population. Analysis of museum samples alone identified three distinct genotype clusters and historical connectivity among water bodies within the Truckee River basin. Baseline data from museum collections indicate that the extant Pilot Peak strain represents a remnant of the extirpated lacustrine lineage. Given the limitations on high- quality data when working with a sparse number of preserved museum samples, we acknowledge that, in the end, this may be a more complicated story. However, 2 the paucity of remnant populations in the Truckee River watershed, in combination with data on the distribution of morphological, meristic and genetic data for Lahontan cutthroat trout, suggests that recovery strategies, particularly in the large lacustrine habitats should consider this lineage as an important part of the genetic legacy of this species.

http://rsos.royalsocietypublishing.org/content/4/11/171253

borntoscout
12-13-2017, 09:39 AM
Interesting that Robert Behnke thought the Pilot Peak population to of the "lost" Truckee River strain when it was first discovered in the seventies, but there was no interest in test planting the Pilot Peak fish in Pyramid until after the UNR work to confirm their DNA match preserved specimens of the Pyramid giants. Behnke thought the PP population probably originated from too small a number of individuals too contain the entire genome, particularly in consideration of the many genrerations they were removed from lake conditions.