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Fishery Bulletin 106(3) 
portions of mainland Russia were distinct from popula- 
tions in western Alaska (Wilmot et al., 1994). Surveys 
of allozyme variation have generally indicated regional 
population differentiation among Russian populations. 
DNA-level markers have substantially increased the 
number of polymorphic loci that are available to be 
included in analyses of genetic variation. Initial sur- 
veys of mitochondrial (mt) DNA variation indicated 
regional differentiation between Sakhalin Island and 
mainland populations (Ginatulina, 1992). Later analy- 
ses of additional mtDNA variation indicated marked 
differentiation between Japanese and Russian popula- 
tions (Sato et al., 2004), and some differentiation among 
Russian populations (Brykov et al., 2003; Polyakova et 
al., 2006). Limited examinations of minisatellite varia- 
tion have indicated some level of differentiation between 
Japanese and Russian populations, but have yielded 
little evidence of regional structure for Russian popula- 
tions (Taylor et al., 1994; Beacham, 1996). 
Analyses of microsatellite variation have been ef- 
fective for determining salmonid population structure 
in local areas (Small et al., 1998; Banks et al., 2000; 
Beacham et al., 2004), as well as broad-scale differences 
across the Pacific Rim (Beacham et al., 2005, 2006). 
Microsatellites have also been of considerable value in 
estimating stock composition in mixed-stock salmon 
fisheries, on both a population-specific (Beacham et al., 
2003) and regional basis (Beacham et al., 2006). Micro- 
satellite variation in chum salmon provides the means 
to examine fine-scale population structure (Chen et al., 
2005), as well as the means for fine-scale estimation of 
stock composition in mixed-stock fisheries (Beacham 
et al., in press). Analyses of microsatellite variation in 
Russian chum populations would likely be of value by 
providing increased resolution of population structure 
compared with that provided by previous techniques, 
and would likely aid in increasing accuracy and preci- 
sion of estimates of stock composition in mixed-stock 
fishery samples. 
Our objectives were to analyze the variation at 14 
microsatellite loci to evaluate population structure of 
Russian chum salmon populations from the far north 
eastern coast of Russia to the more southern areas of 
Primorye and Sakhalin Island, and then to evaluate the 
use of these loci for the practical purpose of providing 
accurate and precise estimates of stock composition in 
mixed-stock fishery samples. Stock composition evalu- 
ation was accomplished by the analysis of simulated 
mixed-stock fishery samples. 
Materials and methods 
Tissue samples were collected from mature chum 
salmon at a number of rivers during previous analyses 
of genetic variation (Winans et al., 1994). Additional 
tissue samples were sent to the Molecular 
Genetics Laboratory at the Pacific Biologi- 
cal Station. The geographic area of the 34 
populations sampled ranged from Primorye 
in the south to northeastern Russia (Fig. 1) 
and encompassed eight geographic regions 
(Table 1). DNA was extracted from the tissue 
samples by a variety of methods, including 
that with chelex resin outlined by Small et al. 
(1998), a Qiagen 96-well Dneasy® procedure 
(Qiagen, Mississauga, Ontario, Canada), or a 
Promega Wizard SV96 Genomic DNA Puri- 
fication system (Promega, Madison, WI). 
Once extracted DNA was available, anal- 
yses of variation at 14 microsatellite loci 
were conducted: Ots3 (Banks et al., 1999), 
Oke3 (Buchholz et al., 2001), Oki2 (Smith 
et al., 1998), OkilOO (primer sequence 5' 
to 3' F: GGTGTTTTAATGTTGTTTCCT, R: 
GTTTCCAGAGTAGTCATCTCTG), Omml070 
(Rexroad et al., 2001), Omy 1011 (Spies et al., 
2005), One 101, Onel02, Onel04, Onelll, and 
Onell4 (Olsen et al., 2000), Otsl03 (Nelson 
and Beacham, 1999), Ssa419 (Cairney et 
al., 2000), and OtsG68 (Williamson et al., 
2002 ). 
In general, PCR DNA amplifications were 
conducted by using DNA Engine Cycler Tet- 
rad2 (BioRad, Hercules, CA) in 6-pL volumes 
consisting of 0.15 units of Taq polymerase, 
1 pL (25-50 ng) of extracted DNA, lx PCR buf- 
fer (Qiagen, Mississauga, Ontario, Canada), 
! 40 °£ 180 ° 
Figure t 
Map indicating the locations in Russia where chum salmon ( Oncorhyn - 
chus keta) from 34 populations or sampling sites were collected. 
Numbers for and locations of populations are indicated in Table 1. 
