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1.
Ecol Evol ; 14(5): e11321, 2024 May.
Article in English | MEDLINE | ID: mdl-38770122

ABSTRACT

Minimally invasive samples are often the best option for collecting genetic material from species of conservation concern, but they perform poorly in many genomic sequencing methods due to their tendency to yield low DNA quality and quantity. Genotyping-in-thousands by sequencing (GT-seq) is a powerful amplicon sequencing method that can genotype large numbers of variable-quality samples at a standardized set of single nucleotide polymorphism (SNP) loci. Here, we develop, optimize, and validate a GT-seq panel for the federally threatened northern Idaho ground squirrel (Urocitellus brunneus) to provide a standardized approach for future genetic monitoring and assessment of recovery goals using minimally invasive samples. The optimized panel consists of 224 neutral and 81 putatively adaptive SNPs. DNA collected from buccal swabs from 2016 to 2020 had 73% genotyping success, while samples collected from hair from 2002 to 2006 had little to no DNA remaining and did not genotype successfully. We evaluated our GT-seq panel by measuring genotype discordance rates compared to RADseq and whole-genome sequencing. GT-seq and other sequencing methods had similar population diversity and F ST estimates, but GT-seq consistently called more heterozygotes than expected, resulting in negative F IS values at the population level. Genetic ancestry assignment was consistent when estimated with different sequencing methods and numbers of loci. Our GT-seq panel is an effective and efficient genotyping tool that will aid in the monitoring and recovery of this threatened species, and our results provide insights for applying GT-seq for minimally invasive DNA sampling techniques in other rare animals.

2.
Insects ; 11(10)2020 Oct 13.
Article in English | MEDLINE | ID: mdl-33065978

ABSTRACT

Polymorphic chromosomal inversions have been implicated in local adaptation. In anopheline mosquitoes, inversions also contribute to epidemiologically relevant phenotypes such as resting behavior. Progress in understanding these phenotypes and their mechanistic basis has been hindered because the only available method for inversion genotyping relies on traditional cytogenetic karyotyping, a rate-limiting and technically difficult approach that is possible only for the fraction of the adult female population at the correct gonotrophic stage. Here, we focus on an understudied malaria vector of major importance in sub-Saharan Africa, Anopheles funestus. We ascertain and validate tag single nucleotide polymorphisms (SNPs) using high throughput molecular assays that allow rapid inversion genotyping of the three most common An. funestus inversions at scale, overcoming the cytogenetic karyotyping barrier. These same inversions are the only available markers for distinguishing two An. funestus ecotypes that differ in indoor resting behavior, Folonzo and Kiribina. Our new inversion genotyping tools will facilitate studies of ecotypic differentiation in An. funestus and provide a means to improve our understanding of the roles of Folonzo and Kiribina in malaria transmission.

3.
G3 (Bethesda) ; 10(9): 3299-3307, 2020 09 02.
Article in English | MEDLINE | ID: mdl-32680855

ABSTRACT

Chromosomal inversion polymorphisms have special importance in the Anopheles gambiae complex of malaria vector mosquitoes, due to their role in local adaptation and range expansion. The study of inversions in natural populations is reliant on polytene chromosome analysis by expert cytogeneticists, a process that is limited by the rarity of trained specialists, low throughput, and restrictive sampling requirements. To overcome this barrier, we ascertained tag single nucleotide polymorphisms (SNPs) that are highly correlated with inversion status (inverted or standard orientation). We compared the performance of the tag SNPs using two alternative high throughput molecular genotyping approaches vs. traditional cytogenetic karyotyping of the same 960 individual An. gambiae and An. coluzzii mosquitoes sampled from Burkina Faso, West Africa. We show that both molecular approaches yield comparable results, and that either one performs as well or better than cytogenetics in terms of genotyping accuracy. Given the ability of molecular genotyping approaches to be conducted at scale and at relatively low cost without restriction on mosquito sex or developmental stage, molecular genotyping via tag SNPs has the potential to revitalize research into the role of chromosomal inversions in the behavior and ongoing adaptation of An. gambiae and An. coluzzii to environmental heterogeneities.


Subject(s)
Anopheles , Malaria , Africa, Western , Animals , Anopheles/genetics , Chromosome Inversion , Genotype , Mosquito Vectors
4.
Mol Ecol Resour ; 20(1): 114-124, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31483931

ABSTRACT

Minimally invasive sampling (MIS) is widespread in wildlife studies; however, its utility for massively parallel DNA sequencing (MPS) is limited. Poor sample quality and contamination by exogenous DNA can make MIS challenging to use with modern genotyping-by-sequencing approaches, which have been traditionally developed for high-quality DNA sources. Given that MIS is often more appropriate in many contexts, there is a need to make such samples practical for harnessing MPS. Here, we test the ability for Genotyping-in-Thousands by sequencing (GT-seq), a multiplex amplicon sequencing approach, to effectively genotype minimally invasive cloacal DNA samples collected from the Western Rattlesnake (Crotalus oreganus), a threatened species in British Columbia, Canada. As there was no previous genetic information for this species, an optimized panel of 362 SNPs was selected for use with GT-seq from a de novo restriction site-associated DNA sequencing (RADseq) assembly. Comparisons of genotypes generated within and among RADseq and GT-seq for the same individuals found low rates of genotyping error (GT-seq: 0.50%; RADseq: 0.80%) and discordance (2.57%), the latter likely due to the different genotype calling models employed. GT-seq mean genotype discordance between blood and cloacal swab samples collected from the same individuals was also minimal (1.37%). Estimates of population diversity parameters were similar across GT-seq and RADseq data sets, as were inferred patterns of population structure. Overall, GT-seq can be effectively applied to low-quality DNA samples, minimizing the inefficiencies presented by exogenous DNA typically found in minimally invasive samples and continuing the expansion of molecular ecology and conservation genetics in the genomics era.


Subject(s)
Crotalus/genetics , DNA/genetics , Genotyping Techniques/methods , High-Throughput Nucleotide Sequencing/methods , Animals , British Columbia , Endangered Species , Genomics , Genotype , Polymorphism, Single Nucleotide
5.
Ecol Evol ; 7(23): 10350-10360, 2017 12.
Article in English | MEDLINE | ID: mdl-29238560

ABSTRACT

Coho salmon were extirpated in the mid-20th century from the interior reaches of the Columbia River but were reintroduced with relatively abundant source stocks from the lower Columbia River near the Pacific coast. Reintroduction of Coho salmon to the interior Columbia River (Wenatchee River) using lower river stocks placed selective pressures on the new colonizers due to substantial differences with their original habitat such as migration distance and navigation of six additional hydropower dams. We used restriction site-associated DNA sequencing (RAD-seq) to genotype 5,392 SNPs in reintroduced Coho salmon in the Wenatchee River over four generations to test for signals of temporal structure and adaptive variation. Temporal genetic structure among the three broodlines of reintroduced fish was evident among the initial return years (2000, 2001, and 2002) and their descendants, which indicated levels of reproductive isolation among broodlines. Signals of adaptive variation were detected from multiple outlier tests and identified candidate genes for further study. This study illustrated that genetic variation and structure of reintroduced populations are likely to reflect source stocks for multiple generations but may shift over time once established in nature.

6.
Mol Ecol Resour ; 15(6): 1421-34, 2015 Nov.
Article in English | MEDLINE | ID: mdl-25737187

ABSTRACT

Twelve eulachon (Thaleichthys pacificus, Osmeridae) populations ranging from Cook Inlet, Alaska and along the west coast of North America to the Columbia River were examined by restriction-site-associated DNA (RAD) sequencing to elucidate patterns of neutral and adaptive variation in this high geneflow species. A total of 4104 single-nucleotide polymorphisms (SNPs) were discovered across the genome, with 193 putatively adaptive SNPs as determined by F(ST) outlier tests. Estimates of population structure in eulachon with the putatively adaptive SNPs were similar, but provided greater resolution of stocks compared with a putatively neutral panel of 3911 SNPs or previous estimates with 14 microsatellites. A cline of increasing measures of genetic diversity from south to north was found in the adaptive panel, but not in the neutral markers (SNPs or microsatellites). This may indicate divergent selective pressures in differing freshwater and marine environments between regional eulachon populations and that these adaptive diversity patterns not seen with neutral markers could be a consideration when determining genetic boundaries for conservation purposes. Estimates of effective population size (N(e)) were similar with the neutral SNP panel and microsatellites and may be utilized to monitor population status for eulachon where census sizes are difficult to obtain. Greater differentiation with the panel of putatively adaptive SNPs provided higher individual assignment accuracy compared to the neutral panel or microsatellites for stock identification purposes. This study presents the first SNPs that have been developed for eulachon, and analyses with these markers highlighted the importance of integrating genome-wide neutral and adaptive genetic variation for the applications of conservation and management.


Subject(s)
Genetic Markers , Genetic Variation , Osmeriformes/classification , Osmeriformes/genetics , Animals , Microsatellite Repeats , North America , Polymorphism, Single Nucleotide , Selection, Genetic
7.
BMC Genomics ; 16: 103, 2015 Feb 21.
Article in English | MEDLINE | ID: mdl-25765850

ABSTRACT

BACKGROUND: As ectothermic organisms have evolved to differing aquatic climates, the molecular basis of thermal adaptation is a key area of research. In this study, we tested for differential transcriptional response of ecologically divergent populations of redband trout (Oncorhynchus mykiss gairdneri) that have evolved in desert and montane climates. Each pure strain and their F1 cross were reared in a common garden environment and exposed over four weeks to diel water temperatures that were similar to those experienced in desert climates within the species' range. Gill tissues were collected from the three strains of fish (desert, montane, F1 crosses) at the peak of heat stress and tested for mRNA expression differences across the transcriptome with RNA-seq. RESULTS: Strong differences in transcriptomic response to heat stress were observed across strains confirming that fish from desert environments have evolved diverse mechanisms to cope with stressful environments. As expected, a large number of total transcripts (12,814) were differentially expressed in the study (FDR ≤ 0.05) with 2310 transcripts in common for all three strains, but the desert strain had a larger number of unique differentially expressed transcripts (2875) than the montane (1982) or the F1 (2355) strain. Strongly differentiated genes (>4 fold change and FDR ≤ 0.05) were particularly abundant in the desert strain (824 unique contigs) relative to the other two strains (montane = 58; F1 = 192). CONCLUSIONS: This study demonstrated patterns of acclimation (i.e., phenotypic plasticity) within strains and evolutionary adaptation among strains in numerous genes throughout the transcriptome. Key stress response genes such as molecular chaperones (i.e., heat shock proteins) had adaptive patterns of gene expression among strains, but also a much higher number of metabolic and cellular process genes were differentially expressed in the desert strain demonstrating these biological pathways are critical for thermal adaptation to warm aquatic climates. The results of this study further elucidate the molecular basis for thermal adaptation in aquatic ecosystems and extend the potential for identifying genes that may be critical for adaptation to changing climates.


Subject(s)
Adaptation, Physiological/genetics , Gene Expression Profiling , Heat-Shock Proteins/biosynthesis , Heat-Shock Response/genetics , Animals , Ecology , Gene Expression Regulation , Heat-Shock Proteins/genetics , Hot Temperature , Oncorhynchus mykiss/genetics , Oncorhynchus mykiss/physiology
8.
Mol Ecol Resour ; 15(4): 855-67, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25476721

ABSTRACT

Genotyping-in-Thousands by sequencing (GT-seq) is a method that uses next-generation sequencing of multiplexed PCR products to generate genotypes from relatively small panels (50-500) of targeted single-nucleotide polymorphisms (SNPs) for thousands of individuals in a single Illumina HiSeq lane. This method uses only unlabelled oligos and PCR master mix in two thermal cycling steps for amplification of targeted SNP loci. During this process, sequencing adapters and dual barcode sequence tags are incorporated into the amplicons enabling thousands of individuals to be pooled into a single sequencing library. Post sequencing, reads from individual samples are split into individual files using their unique combination of barcode sequences. Genotyping is performed with a simple perl script which counts amplicon-specific sequences for each allele, and allele ratios are used to determine the genotypes. We demonstrate this technique by genotyping 2068 individual steelhead trout (Oncorhynchus mykiss) samples with a set of 192 SNP markers in a single library sequenced in a single Illumina HiSeq lane. Genotype data were 99.9% concordant to previously collected TaqMan(™) genotypes at the same 192 loci, but call rates were slightly lower with GT-seq (96.4%) relative to Taqman (99.0%). Of the 192 SNPs, 187 were genotyped in ≥90% of the individual samples and only 3 SNPs were genotyped in <70% of samples. This study demonstrates amplicon sequencing with GT-seq greatly reduces the cost of genotyping hundreds of targeted SNPs relative to existing methods by utilizing a simple library preparation method and massive efficiency of scale.


Subject(s)
Genotyping Techniques/economics , Genotyping Techniques/methods , High-Throughput Nucleotide Sequencing/economics , High-Throughput Nucleotide Sequencing/methods , Polymorphism, Single Nucleotide , Animals , Computational Biology/economics , Computational Biology/methods , Cost-Benefit Analysis , Oncorhynchus mykiss/classification , Oncorhynchus mykiss/genetics
9.
Mol Ecol Resour ; 15(1): 187-202, 2015 01.
Article in English | MEDLINE | ID: mdl-24842551

ABSTRACT

Next-generation sequencing data can be mined for highly informative single nucleotide polymorphisms (SNPs) to develop high-throughput genomic assays for nonmodel organisms. However, choosing a set of SNPs to address a variety of objectives can be difficult because SNPs are often not equally informative. We developed an optimal combination of 96 high-throughput SNP assays from a total of 4439 SNPs identified in a previous study of Pacific lamprey (Entosphenus tridentatus) and used them to address four disparate objectives: parentage analysis, species identification and characterization of neutral and adaptive variation. Nine of these SNPs are FST outliers, and five of these outliers are localized within genes and significantly associated with geography, run-timing and dwarf life history. Two of the 96 SNPs were diagnostic for two other lamprey species that were morphologically indistinguishable at early larval stages and were sympatric in the Pacific Northwest. The majority (85) of SNPs in the panel were highly informative for parentage analysis, that is, putatively neutral with high minor allele frequency across the species' range. Results from three case studies are presented to demonstrate the broad utility of this panel of SNP markers in this species. As Pacific lamprey populations are undergoing rapid decline, these SNPs provide an important resource to address critical uncertainties associated with the conservation and recovery of this imperiled species.


Subject(s)
Genotype , Genotyping Techniques/methods , High-Throughput Screening Assays , Lampreys/classification , Lampreys/genetics , Polymorphism, Single Nucleotide , Sequence Analysis, DNA , Animals , Genetic Markers , Molecular Sequence Data
10.
G3 (Bethesda) ; 4(12): 2473-81, 2014 Oct 28.
Article in English | MEDLINE | ID: mdl-25354781

ABSTRACT

Recent advances in genotyping-by-sequencing have enabled genome-wide association studies in nonmodel species including those in aquaculture programs. As with other aquaculture species, rainbow trout and steelhead (Oncorhynchus mykiss) are susceptible to disease and outbreaks can lead to significant losses. Fish culturists have therefore been pursuing strategies to prevent losses to common pathogens such as Flavobacterium psychrophilum (the etiological agent for bacterial cold water disease [CWD]) and infectious hematopoietic necrosis virus (IHNV) by adjusting feed formulations, vaccine development, and selective breeding. However, discovery of genetic markers linked to disease resistance offers the potential to use marker-assisted selection to increase resistance and reduce outbreaks. For this study we sampled juvenile fish from 40 families from 2-yr classes that either survived or died after controlled exposure to either CWD or IHNV. Restriction site-associated DNA sequencing produced 4661 polymorphic single-nucleotide polymorphism loci after strict filtering. Genotypes from individual survivors and mortalities were then used to test for association between disease resistance and genotype at each locus using the program TASSEL. After we accounted for kinship and stratification of the samples, tests revealed 12 single-nucleotide polymorphism markers that were highly associated with resistance to CWD and 19 markers associated with resistance to IHNV. These markers are candidates for further investigation and are expected to be useful for marker assisted selection in future broodstock selection for various aquaculture programs.


Subject(s)
Disease Resistance/genetics , Oncorhynchus mykiss/genetics , Animals , Chromosome Mapping , DNA Restriction Enzymes/metabolism , Fish Diseases/microbiology , Flavobacteriaceae Infections/microbiology , Flavobacteriaceae Infections/veterinary , Flavobacterium/physiology , Genetic Loci , Genetic Markers/genetics , Genome-Wide Association Study , Genotype , Infectious hematopoietic necrosis virus/physiology , Linkage Disequilibrium , Polymorphism, Single Nucleotide , Rhabdoviridae Infections/veterinary , Rhabdoviridae Infections/virology , Sequence Analysis, DNA
11.
Mol Ecol ; 22(11): 3090-7, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23452191

ABSTRACT

To elucidate the mechanisms of thermal adaptation and acclimation in ectothermic aquatic organisms from differing climates, we used a common-garden experiment for thermal stress to investigate the heat shock response of redband trout (Oncorhynchus mykiss gairdneri) from desert and montane populations. Evidence for adaptation was observed as expression of heat shock genes in fish from the desert population was more similar to control (unstressed) fish and significantly different (P ≤ 0.05) from those from the montane population, while F1 crosses were intermediate. High induction of heat shock proteins (Hsps) in the montane strain appeared to improve short-term survival during first exposure to high water temperatures, but high physiological costs of Hsp production may have led to lower long-term survival. In contrast, the desert strain had significantly lower heat shock response than the montane fish and F1 crosses, suggesting that these desert fish have evolved alternative mechanisms to deal with thermal stress that provide better balance of physiological costs. Genomewide tests of greater than 10 000 SNPs found multiple SNPs that were significantly associated with survival under thermal stress, including Hsp47 which consistently appeared as a strong candidate gene for adaption to desert climates. Candidate SNPs identified in this study are prime targets to screen more broadly across this species' range to predict the potential for adaptation under scenarios of climate change. These results demonstrate that aquatic species can evolve adaptive responses to thermal stress and provide insight for understanding how climate change may impact ectotherms.


Subject(s)
Acclimatization/genetics , HSP47 Heat-Shock Proteins/genetics , Heat-Shock Response/genetics , Oncorhynchus mykiss/genetics , Oncorhynchus mykiss/physiology , Acclimatization/physiology , Animals , Climate Change , Desert Climate , Gene Expression , Genome-Wide Association Study , HSP47 Heat-Shock Proteins/biosynthesis , HSP47 Heat-Shock Proteins/metabolism , Heat-Shock Response/physiology , Hot Temperature , Hydrobiology , Oncorhynchus mykiss/metabolism , Polymorphism, Single Nucleotide , Stress, Physiological
12.
Mol Ecol ; 22(11): 3061-76, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23106605

ABSTRACT

Little is known of the genetic basis of migration despite the ecological benefits migratory species provide to their communities and their rapid global decline due to anthropogenic disturbances in recent years. Using next-generation sequencing of restriction-site-associated DNA (RAD) tags, we genotyped thousands of single nucleotide polymorphisms (SNPs) in two wild populations of migratory steelhead and resident rainbow trout (Oncorhynchus mykiss) from the Pacific Northwest of the United States. One population maintains a connection to the sea, whereas the other population has been sequestered from its access to the ocean for more than 50 years by a hydropower dam. Here we performed a genome-wide association study to identify 504 RAD SNP markers from several genetic regions that were associated with the propensity to migrate both within and between the populations. Our results corroborate those in previous quantitative trait loci studies and provide evidence for additional loci associated with this complex migratory life history. Our results suggest a complex multi-genic basis with several loci of small effect distributed throughout the genome contributing to migration in this species. We also determined that despite being sequestered for decades, the landlocked population continues to harbour genetic variation associated with a migratory life history and ATPase activity. Furthermore, we demonstrate the utility of genotyping-by-sequencing and how RAD-tag SNP data can be readily compared between studies to investigate migration within this species.


Subject(s)
Animal Migration , Oncorhynchus mykiss/genetics , Animals , Base Sequence , Chromosome Mapping , Female , Genetic Markers , Genetic Variation , Genome-Wide Association Study , Genotype , High-Throughput Nucleotide Sequencing , Male , Northwestern United States , Polymorphism, Single Nucleotide , Quantitative Trait Loci , Sequence Analysis, DNA
13.
Mol Ecol ; 22(11): 2898-916, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23205767

ABSTRACT

Unlike most anadromous fishes that have evolved strict homing behaviour, Pacific lamprey (Entosphenus tridentatus) seem to lack philopatry as evidenced by minimal population structure across the species range. Yet unexplained findings of within-region population genetic heterogeneity coupled with the morphological and behavioural diversity described for the species suggest that adaptive genetic variation underlying fitness traits may be responsible. We employed restriction site-associated DNA sequencing to genotype 4439 quality filtered single nucleotide polymorphism (SNP) loci for 518 individuals collected across a broad geographical area including British Columbia, Washington, Oregon and California. A subset of putatively neutral markers (N = 4068) identified a significant amount of variation among three broad populations: northern British Columbia, Columbia River/southern coast and 'dwarf' adults (F(CT) = 0.02, P ≪ 0.001). Additionally, 162 SNPs were identified as adaptive through outlier tests, and inclusion of these markers revealed a signal of adaptive variation related to geography and life history. The majority of the 162 adaptive SNPs were not independent and formed four groups of linked loci. Analyses with matsam software found that 42 of these outlier SNPs were significantly associated with geography, run timing and dwarf life history, and 27 of these 42 SNPs aligned with known genes or highly conserved genomic regions using the genome browser available for sea lamprey. This study provides both neutral and adaptive context for observed genetic divergence among collections and thus reconciles previous findings of population genetic heterogeneity within a species that displays extensive gene flow.


Subject(s)
Adaptation, Physiological/genetics , Gene Flow , Lampreys/genetics , Animals , Base Sequence , Genetic Variation , Genetics, Population , Genomics , Genotype , Geography , High-Throughput Nucleotide Sequencing , Pacific Ocean , Phylogeny , Polymorphism, Single Nucleotide , Sequence Analysis, DNA
14.
Mol Ecol Resour ; 13(2): 276-88, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23253773

ABSTRACT

The Lahontan cutthroat trout (Oncorhynchus clarkii henshawi) is threatened by habitat destruction, over-harvest and hybridization with nonnative trout. Currently, three Geographic Management Units (GMUs) are recognized within the taxon. Here, we describe a suite of 68 single-nucleotide polymorphism (SNP) genetic markers for use in the study and management of Lahontan cutthroat trout and a closely related subspecies, the Paiute cutthroat trout (O. c. seleneris). These include markers variable within the two subspecies (n = 35), diagnostic for the two subspecies (n = 23) and diagnostic for Yellowstone cutthroat trout (O. c. bouvieri) and other closely related subspecies (n = 10). Sixty-three markers were discovered by Sanger sequencing of 171 EST loci in an ascertainment panel including Lahontan cutthroat trout from four populations representing all GMUs. Five markers were identified in a secondary sequencing effort with a single population of Lahontan cutthroat trout. TaqMan assays were validated on six Lahontan cutthroat trout populations and a diverse panel of other trout. Over 90% of the markers variable in Lahontan cutthroat trout were polymorphic in at least two populations, and 66% were variable within all three GMUs. All Lahontan diagnostic markers were also fixed for the Lahontan allele in Paiute cutthroat trout. Most of the Yellowstone diagnostic markers can also be used for this purpose in other cutthroat trout subspecies. This is the first set of SNP markers to be developed for Lahontan cutthroat trout, and will be an important tool for conservation and management.


Subject(s)
Conservation of Natural Resources/methods , Genetic Markers , Oncorhynchus/genetics , Animals , Expressed Sequence Tags , Fish Proteins/genetics , Genomics , Genotype , Oncorhynchus/classification , Polymorphism, Single Nucleotide
15.
Mol Ecol Resour ; 11 Suppl 1: 20-30, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21429160

ABSTRACT

Single-nucleotide polymorphisms (SNPs) have potential for broad application in population and conservation genetics, but availability of these markers is limited in many nonmodel species. In this study, genomic and expressed sequence tagged (EST) sequences from closely related salmonids (Chinook salmon and rainbow trout) were used to design primers for amplification and sequencing of sockeye (Oncorhynchus nerka) and coho (Oncorhynchus kisutch) salmon DNA for SNP discovery. One hundred and six primer sets were designed and tested for amplification in each species. An ascertainment panel of 32 diverse individuals from each species was used as template for PCR amplification and Sanger sequencing. In total, 21,647 bases of consensus sequence were screened in sockeye salmon and 20,784 bases in coho salmon with 93 and 149 SNP sites identified, respectively. Sixty-four SNP sites were chosen for assay development, and 54 of the assays were validated by comparison with genotype and sequence data (O. nerka = 23; O. kisutch = 31). These validated SNP assays along with 142 other available SNP assays [O. nerka = 103 (126 total); O. kisutch = 30 (61 total)] were used to genotype collections of O. nerka (N = 5) and O. kisutch (N = 4) from various sites in the Columbia River to evaluate the utility of these markers in this region. Results from factorial correspondence analysis indicate that these SNP markers are capable of distinguishing O. nerka populations, but O. kisutch collections were less distinct because of their common ancestry.


Subject(s)
Oncorhynchus kisutch/genetics , Polymorphism, Single Nucleotide , Salmon/genetics , Animals , Consensus Sequence , DNA Primers , Expressed Sequence Tags , Genotype , Northwestern United States , Rivers , Sequence Analysis, DNA
16.
Mol Ecol ; 19(21): 4622-37, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20880387

ABSTRACT

Natural populations that evolve under extreme climates are likely to diverge because of selection in local environments. To explore whether local adaptation has occurred in redband trout (Oncorhynchus mykiss gairdneri) occupying differing climate regimes, we used a limited genome scan approach to test for candidate markers under selection in populations occurring in desert and montane streams. An environmental approach to identifying outlier loci, spatial analysis method and linear regression of minor allele frequency with environmental variables revealed six candidate markers (P < 0.01). Putatively neutral markers identified high genetic differentiation among desert populations relative to montane sites, likely due to intermittent flows in desert streams. Additionally, populations exhibited a highly significant pattern of isolation by temperature (P< 0.0001) and those adapted to the same environment had similar allele frequencies across candidate markers, indicating selection for differing climates. These results imply that many genes are involved in the adaptation of redband trout to differing environments, and selection acts to reinforce localization. The potential to predict genetic adaptability of individuals and populations to changing environmental conditions may have profound implications for species that face extensive anthropogenic disturbances.


Subject(s)
Adaptation, Physiological/genetics , Environment , Genetic Variation , Oncorhynchus mykiss/genetics , Selection, Genetic , Animals , Ecosystem , Evolution, Molecular , Gene Frequency , Genetics, Population , Genotype , Idaho , Polymorphism, Single Nucleotide
17.
J Hered ; 101(1): 107-12, 2010.
Article in English | MEDLINE | ID: mdl-19773392

ABSTRACT

Heat shock proteins (Hsps) are induced in response to high temperatures and other stressors, and sequence variation plays a role in regulation of expression of these genes. In this study, we investigated the sequence variation in the 3 major classes of Hsps (Hsp90, Hsp70, and low-molecular weight Hsp) within and among 3 cold-water fish species of Oncorhynchus (Oncorhynchus clarki, Oncorhynchus mykiss, and Oncorhynchus tshawytscha) with variable life history and thermal tolerance characteristics. Sequences collectively totaled 4556 bp across 9 gene fragments and 198 single nucleotide polymorphisms and 43 indel sites were observed among species. Within species, sequence variation was much lower for O. clarki than the other 2 species. Sequence variation within and among species was high in cis-regulatory regions that are potentially involved in transcription of Hsps under variable stressors. Our results indicate that Hsp genes may be locally adapted in O. clarki, whereas higher Hsp polymorphism is necessary for O. mykiss and O. tshawytscha and variation at the sequence level may have important evolutionary consequences for these species. Further studies are needed to determine the association of observed sequence variation with the regulation of Hsps and performance of fish under stress.


Subject(s)
Heat-Shock Proteins/genetics , Oncorhynchus/genetics , 3' Untranslated Regions , Animals , Base Sequence , DNA Primers , Polymorphism, Single Nucleotide
18.
Mol Ecol Resour ; 9(1): 318-22, 2009 Jan.
Article in English | MEDLINE | ID: mdl-21564638

ABSTRACT

Thirty-two individuals representing coastal and inland populations of steelhead and rainbow trout (Oncorhynchus mykiss) were sequenced at 18 expressed sequence tags and nine microsatellite loci to identify single nucleotide polymorphisms. A total of 98 polymorphisms were discovered during the screen and 22 were developed into 5' exonuclease assays (Taqman assays). Genotypes from TaqMan assays were compared to sequence data from individuals in the ascertainment panel to confirm proper allele designations. A larger number of samples (n = 192) from six regions were tested with the validated assays. Per-locus F(ST) values ranged from 0.001 to 0.414.

19.
Mol Ecol Resour ; 9(6): 1460-6, 2009 Nov.
Article in English | MEDLINE | ID: mdl-21564933

ABSTRACT

This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium dahliae, Wasmannia auropunctata, and Zygochlamys patagonica. These loci were cross-tested on the following species: Chaetodon baronessa, Falco columbarius, Falco eleonorae, Falco naumanni, Falco peregrinus, Falco subbuteo, Didelphis aurita, Gracilinanus microtarsus, Marmosops paulensis, Monodelphis Americana, Odontesthes hatcheri, Podocarpus grayi, Podocarpus lawrencei, Podocarpus smithii, Portunus pelagicus, Syngnathus acus, Syngnathus typhle,Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvauceli and Verticillium albo-atrum. This article also documents the addition of nine sequencing primer pairs and sixteen allele specific primers or probes for Oncorhynchus mykiss and Oncorhynchus tshawytscha; these primers and assays were cross-tested in both species.

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