Eric C AndersonSouthwest Fisheries Science Center · Fisheries Ecology Division
Eric C Anderson
Ph.D.
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Introduction
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Publications
Publications (116)
Populations composed of individuals descended from multiple distinct genetic lineages often feature significant differences in phenotypic frequencies. We considered hatchery production of steelhead, the migratory anadromous form of the salmonid species Oncorhynchus mykiss, and investigated how differences among genetic lineages and environmental va...
Low‐coverage whole‐genome sequencing (WGS) is increasingly used for the study of evolution and ecology in both model and non‐model organisms; however, effective application of low‐coverage WGS data requires the implementation of probabilistic frameworks to account for the uncertainties in genotype likelihoods.
Here, we present a probabilistic frame...
Migration is driven by a combination of environmental and genetic factors, but many questions remain about those drivers. Potential interactions between genetic and environmental variants associated with different migratory phenotypes are rarely the focus of study. We pair low coverage whole genome resequencing with a de novo genome assembly to exa...
Life‐history variation is the raw material of adaptation, and understanding its genetic and environmental underpinnings is key to designing effective conservation strategies. We used large‐scale genetic pedigree reconstruction of anadromous steelhead trout ( Oncorhynchus mykiss ) from the Russian River, CA, USA, to elucidate sex‐specific patterns o...
Understanding the geographic linkages among populations across the annual cycle is an essential component for understanding the ecology and evolution of migratory species and for facilitating their effective conservation. While genetic markers have been widely applied to describe migratory connections, the rapid development of new sequencing method...
Understanding the geographic linkages among populations across the annual cycle is an essential component for understanding the ecology and evolution of migratory species and for facilitating their effective conservation. While genetic markers have been widely applied to describe migratory connections, the rapid development of new sequencing method...
Low-coverage whole genome sequencing (WGS) is increasingly used for the study of evolution and ecology in both model and non-model organisms; however, effective application of low-coverage WGS data requires the implementation of probabilistic frameworks to account for the uncertainties in genotype likelihood data. Here, we present a probabilistic f...
Hybridization between coastal cutthroat trout (Oncorhynchus clarkii clarkii) and steelhead (O. mykiss) was assessed in the Smith River, California. Individuals were categorized as pure or as one of 10 hybrid classes using 30 'diagnostic' single-nucleotide polymorphisms positioned on 26 separate chromosomes. Most of the individuals examined (n = 876...
The increasing feasibility of assembling large genomic datasets for non-model species presents both opportunities and challenges for applied conservation and management. A popular theme in recent studies is the search for large-effect loci that explain substantial portions of phenotypic variance for a key trait(s). If such loci can be linked to ada...
Global fisheries kill millions of seabirds annually through bycatch, but little is known about population‐level impacts, particularly in species that form metapopulations. U.S. North Pacific groundfish fisheries catch thousands of Northern Fulmars (Fulmarus glacialis rodgersii) each year, making fulmars the most frequently caught seabird in federal...
Genetic changes underlying adaptation vary greatly in terms of complexity and, within the same species, genetic responses to similar selective pressures may or may not be the same. We examine both complex (supergene) and simple (SNP) genetic variants occurring in populations of rainbow trout (Oncorhynchus mykiss) independently isolated from ocean a...
Identifying population genetic structure is useful for inferring evolutionary process and comparing the resulting structure with subspecies boundaries can aid in species management. The American Kestrel (Falco sparverius) is a widespread and highly diverse species with 17 total subspecies, only 2 of which are found north of U.S./Mexico border (F. s...
Global loss of biodiversity has placed new urgency on the need to understand factors regulating species response to rapid environmental change. While specialists are often less resilient to rapid environmental change than generalists, species‐level analyses may obscure the extent of specialization when locally adapted populations vary in climate to...
Unexpectedly simple
Chinook salmon are known to return to spawn at two distinct times of the year: spring and fall. Individuals that return during these times have generally been referred to as parts of distinct groups, or ecotypes, with traits specific to their timing and presumed divergence being caused by the lack of interbreeding. By looking at...
Inferring the evolutionary dynamics at play during the process of speciation by analysing the genomic landscape of divergence is a major pursuit in population genomics. However, empirical assessments of genomic landscapes under varying evolutionary scenarios that are known a priori are few, thereby limiting our ability to achieve this goal. Here we...
A goal of the genomic era is to infer the evolutionary dynamics at play during the process of speciation by analysing the genomic landscape of divergence. However, empirical assessments of genomic landscapes under varying evolutionary scenarios are few, limiting the ability to achieve this goal. Here we combine RAD-sequencing and individual-based s...
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Males and females often differ in their fitness optima for shared traits that have a shared genetic basis, leading to sexual conflict. Morphologically differentiated sex chromosomes can resolve this conflict and protect sexually antagonistic variation, but they accumulate deleterious mutations. However, how sexual conflict is resolved in species th...
The way that organisms diverge into reproductively isolated species is a major question in biology. The recent accumulation of genomic data provides promising opportunities to understand the genomic landscape of divergence, which describes the distribution of differences across genomes. Genomic areas of unusually high differentiation have been call...
1. The way that organisms diverge into reproductively isolated species is a major question in biology. The recent accumulation of genomic data provides promising opportunities to understand the genomic landscape of divergence, which describes the distribution of differences across genomes. Genomic areas of unusually high differentiation have been c...
Marine species with pelagic larvae typically exhibit little population structure, suggesting long distance dispersal and high gene flow. Directly quantifying dispersal of marine fishes is challenging but important, particularly for design of marine protected areas (MPAs). Here, we studied kelp rockfish (Sebastes atrovirens) sampled along ~25 km of...
Traits with different fitness optima in males and females cause sexual conflict when they have a shared genetic basis. Heteromorphic sex chromosomes can resolve this conflict and protect sexually antagonistic polymorphisms but accumulate deleterious mutations. However, many taxa lack differentiated sex chromosomes, and how sexual conflict is resolv...
Domestication is rife with episodes of interbreeding between cultured and wild populations, potentially challenging adaptive variation in the wild. In Atlantic salmon, Salmo salar, the number of domesticated individuals far exceeds wild individuals, and escape events occur regularly, yet evidence of the magnitude and geographic scale of interbreedi...
Hybridization between wild and escaped cultured Atlantic salmon (Salmo salar) can threaten the stability and persistence of locally adapted wild populations. Here we describe the development and validation of a genomic-based approach to quantify recent hybridization between escapee and wild salmon in the western Atlantic. Based on genome-wide singl...
Genetic stock identification (GSI) estimates stock proportions and individual assignments through comparison of genetic markers with reference populations. It is used widely in anadromous fisheries to estimate the impact of oceanic harvest on riverine populations. Here, we provide a formal, explicit description of Bayesian inference in the conditio...
New computational methods and next generation sequencing (NGS) approaches have enabled the use of thousands or hundreds of thousands of genetic markers to address previously intractable questions. The methods and massive marker sets present both new data analysis challenges and opportunities to visualize, understand, and apply population and conser...
Few regions have been more severely impacted by climate change in the USA than the Desert Southwest. Here, we use ecological genomics to assess the potential for adaptation to rising global temperatures in a widespread songbird, the willow flycatcher (Empidonax traillii), and find the endangered desert southwestern subspecies (E. t. extimus) most v...
Individual assignment and genetic mixture analysis are commonly utilized in contemporary wildlife and fisheries management. Although microsatellite loci provide unparalleled numbers of alleles per locus, their use in assignment applications is increasingly limited. However, next-generation sequencing, in conjunction with novel bioinformatic tools a...
The accelerating rate at which DNA sequence data is now generated by high-throughput sequencing instruments provides both opportunities and challenges for population genetic and ecological investigations of animals and plants. We show here how the common practice of calling genotypes from a single SNP per sequenced region ignores substantial additi...
Polyploid organisms pose substantial obstacles to genetic analysis, as molecular assay data are usually difficult to evaluate in a Mendelian framework. Green sturgeon (Acipenser medirostris) is a tetraploid species and is facing significant conservation challenges, including bycatch in ocean fisheries. We present here novel molecular genetic assays...
The ability to detect and characterize hybridization in nature has long been of interest to many fields of biology and often has direct implications for wildlife management and conservation. The capacity to identify the presence of hybridization, and quantify the numbers of individuals belonging to different hybrid classes, permits inference on the...
The little greenbul, a common rainforest passerine from sub-Saharan Africa, has been the subject of long-term evolutionary studies to understand the mechanisms leading to rainforest speciation. Previous research found morphological and behavioral divergence across rainforest-savanna transition zones (ecotones), and a pattern of divergence with gene...
The effective population size (N
e
) is a fundamental parameter in population genetics that determines the relative strength of selection and random genetic drift, the effect of migration, levels of inbreeding, and linkage disequilibrium. In many cases where it has been estimated in animals, N
e
is on the order of 10%-20% of the census size. In thi...
1.Identifying migratory connections across the annual cycle is important for studies of migrant ecology, evolution, and conservation. While recent studies have demonstrated the utility of high-resolution SNP-based genetic markers for identifying population-specific migratory patterns, the accuracy of this approach relative to other intrinsic taggin...
Results:
1) Unless simulated samples included large family groups together with a component of unrelated individuals, removing siblings generally reduced precision of Pand FST ; 2) Ne based on the linkage-disequilibrium method was largely unbiased using full random samples but became increasingly upwardly biased under aggressive purging of sibling...
Identifying migratory connections across the annual cycle is important for studies of migrant ecology, evolution, and conservation. While recent studies have demonstrated the utility of high-resolution SNP-based genetic markers for identifying population-specific migratory patterns, the accuracy of this approach relative to other intrinsic tagging...
Abstract—In 2-stage fishery sampling, abundance is often estimated by using a primary sampling gear and total abundance is then partitioned into groups of interest by applying data on composition derived from a secondary sampling gear. However, the literature is sparse on statistical properties of estimates of run composition. We examined the accur...
Hybridization among populations and species is a central theme in many areas of biology, and the study of hybridization has direct applicability to testing hypotheses about evolution, speciation, and genetic recombination, as well as having conservation, legal and regulatory implications. Yet, despite being a topic of considerable interest, the ide...
Bycatch of mid-trophic level anadromous fishes that connect marine and freshwater ecosystems is a growing conservation concern. Anadromous alewife (Alosa pseudoharengus) and blueback herring (A. aestivalis) are important components of coastal freshwater and marine food webs, but have experienced dramatic declines in the abundances of spawning adult...
Mark-recapture (MR) methods are commonly used to study wildlife populations. Taking advantage of modern genetics one can generalize from "recapture of self" to "recapture of closely-related kin". Abundance and other demographic parameters of adults can then be estimated using, if necessary, only samples from dead animals (live-release is optional)....
We develop a computational framework for addressing pedigree inference problems using small numbers (80-400) of single nucleotide polymorphisms (SNPs). Our approach relaxes the assumptions, which are commonly made, that sampling is complete with respect to the pedigree and that there is no genotyping error. It relies on representing the inferred pe...
Chinook salmon spawning was first reported in the 1980s in the Caterina River tributary of the Santa Cruz River basin of Patagonia, which drains into the Atlantic Ocean. A naturalized population now persists and its source has been debated. Chinook salmon from California populations was directly released into the Santa Cruz River in the early twent...
The ability to accurately determine the original source of invading species offers several powerful applications in invasive species ecology and management and may enable important information on the invading species in its native habitat. Lake Storsjøen in South-Central Nor-way was recently found to have been subjected to an illegal translocation...
We show that the algorithm in the program FLOCK (Duchesne & Turgeon 2009) can be interpreted as an estimation procedure based on a model essentially identical to the STRUCTURE (Pritchard et al. 2000) model with no admixture and non-correlated allele frequency priors. Rather than using MCMC, the FLOCK algorithm searches for the maximum-a-posteriori...
INTRODUCTION Recently, statistical geneticists have developed a number of model-based methods that use genetic data to infer the population of origin of the gene copies within an individual. In this chapter we focus on three of these methods which are known by the software that implements them: STRUCTURE (Pritchard et al. 2000), NEW HYBRIDS (Anders...
Steelhead Oncorhynchus mykiss are the most widespread of the Pacific salmonids Oncorhynchus spp. and are found in nearly all basins within their native range around the northern Pacific Rim. Here, we elucidate genetic population structure of steelhead in coastal basins from most of their coastal-California range using variation at 15 microsatellite...
Neotropical migratory birds are declining across the Western Hemisphere, but conservation efforts have been hampered by the inability to assess where migrants are most limited – the breeding grounds, migratory stopover sites, or wintering areas. A major challenge has been the lack of an efficient, reliable, and broadly applicable method for measuri...
Anadromous alewife (Alosa pseudoharengus) and blueback herring (A. aestivalis) are species of conservation concern across their ranges. Many populations are at historically low abundances, and bycatch in marine fisheries has been identified as a major threat to recovery efforts. Our prior research revealed that, for both species, genetically distin...
Neotropical migratory birds are declining across the Western Hemisphere, but conservation efforts have been hampered by the inability to assess where migrants are most limited–the breeding grounds, migratory stopover sites, or wintering areas. A major challenge has been the lack of an efficient, reliable, and broadly applicable method for connectin...
Chinook Salmon (Oncorhynchus tshawytscha) is an economically and ecologically important species, and populations from the west coast of North America are a major component of fisheries in the North Pacific Ocean. The anadromous life history strategy of this species generates populations (or stocks) that typically are differentiated from neighboring...
Next-generation sequencing has made it possible to begin asking questions about the process of divergence at the level of the genome. For example, recently there has been a debate around the role of ‘genomic islands of divergence’ (i.e. blocks of outlier loci) in facilitating the process of speciation-with-gene-flow. The Swainson's thrush, Catharus...
Abstract Managing weak stocks in mixed-stock fisheries often relies on proxies derived from data-rich indicator stocks, although there have been limited tests of the appropriateness of such proxies. For example, full cohort reconstruction of tagged Klamath River fall-run Chinook Salmon Oncorhynchus tshawytscha of northern California enables the use...
We develop a model based on the Dirichlet-compound multinomial distribution (CMD) and Ewens Sampling Formula to predict the fraction of SNP loci that will appear fixed for alternate alleles between two pooled samples drawn from the same underlying population. We apply this model to next generation sequencing (NGS) data from Baltic Sea herring recen...
Understanding life history traits is an important first step in formulating effective conservation and management strategies. The use of artificial propagation and supplementation as such a strategy can have numerous effects on the supplemented natural populations and minimizing life history divergence is crucial in minimizing these effects. Here,...
Parentage-based tagging (PBT) is a promising alternative to traditional coded-wire tag (CWT) methodologies for monitoring and evaluating hatchery stocks. This approach involves the genotyping of hatchery broodstock and uses parentage assignments to identify the origin and brood year of their progeny. In this study we empirically confirmed that fewe...
Parentage-based tagging (PBT) is a promising alternative to traditional coded-wire tag (CWT) methodologies for monitoring and evaluating hatchery stocks. This approach involves the genotyping of hatchery broodstock and uses parentage assignments to identify the origin and brood year of their progeny. In this study we empirically confirmed that fewe...
We show the software SOLOMON is improved by using the likelihood ratio instead of an ad hoc statistic.
Code: github.com/eriqande/solidmon/releases/tag/v0.1-bioinformatics
Contact: eric.anderson@noaa.gov
Ecological traits and sexual signals may both contribute to the process of ecological speciation. Here we investigate the roles of an ecological trait, seasonal migratory behaviour and a sexual trait, song, in restricting or directing gene flow across a migratory divide in the Swainson's thrush (Catharus ustulatus). We show that short-distance migr...
Once hunted to the brink of extinction, humpback whales (Megaptera novaeangliae) in the North Atlantic have recently been increasing in numbers. However, uncertain information on past abundance makes it difficult to assess the extent of the recovery in this species. While estimates of pre-exploitation abundance based upon catch data suggest the pop...
Abstract Advances in genotyping that allow tens of thousands of individuals to be genotyped at a moderate number of single nucleotide polymorphisms (SNPs) permit parentage inference to be pursued on a very large scale. The intergenerational tagging this capacity allows is revolutionizing the management of cultured organisms (cows, salmon, etc.) and...
Coho salmon (Oncorhynchus kisutch) populations at the southern extent of their range, in the Central California Coast (CCC) ESU, are in steep decline and are ESA-listed as Endangered. In recent years, the species has disappeared from numerous basins and streams, including most tributaries of the Russian River, and fish that remain show a high level...
More than five years ago we proposed a new way of using genetic data to track the origin and cohort of hatchery salmon called Parentage Based Tagging (PBT). The idea is relatively simple: at the time of spawning, tissue samples from hatchery broodstock are collected, genotyped, and entered into a parent data base. Subsequently, hatchery fish recove...
Chinook salmon is a valuable species for commercial and recreational fisheries in North America. Together with several rockfish species, it constitutes the most important target for marine recreational fisheries along the California Coast. During the last 30 years, a general decline of southern salmon stocks has been noticed, resulting in the recen...
Molecular evaluations of successful invaders are common, however studies of introduced species that have had limited invasion success, or have died out completely, are rare. We studied an introduced population of speckled dace (Rhinichthys osculus) from northern California, USA that has rapidly increased in abundance but remained restricted to a 25...
Pedigree reconstruction using genotypic markers has become an important tool for the study of natural populations. The nonstandard nature of the underlying statistical problems has led to the necessity of developing specialized statistical and computational methods. In this article, a new version of pedigree reconstruction tools (PRT 2.0) is presen...
The threatened Paiute cutthroat trout (Oncorhynchus clarkii seleniris, PCT) is endemic to Silver King Creek, California, USA, which was stocked with non-native trout beginning in 1930. Single nucleotide polymorphism (SNP) and microsatellite data reveal that the trout population in Silver King Creek is weakly structured and composed of introgressed...
It is well known that statistical classification procedures should be assessed using data that are separate from those used to train the classifier. This principle is commonly overlooked when the classification procedure in question is population assignment using a set of genetic markers that were chosen specifically on the basis of their allele fr...
Severe declines in megafauna worldwide illuminate the role of top predators in ecosystem structure. In the Antarctic, the Krill Surplus Hypothesis posits that the killing of more than 2 million large whales led to competitive release for smaller krill-eating species like the Antarctic minke whale. If true, the current size of the Antarctic minke wh...