Mosaic of Somatic Mutations in Earth's Oldest Living Organism, Pando.

Understanding how mutations arise and spread through individuals and populations is fundamental to evolutionary biology. Most organisms have a life cycle with unicellular bottlenecks during reproduction. However, some organisms like plants, fungi, or colonial animals can grow indefinitely, changing the manner in which mutations spread throughout both the individual and the population.

Phenotypic Variation in Phytochemical Defense of Trembling Aspen in Western North America: Genetics, Development, and Geography.

Trembling aspen (Populus tremuloides) is arguably the most important deciduous tree species in the Intermountain West of North America. There, as elsewhere in its range, aspen exhibits remarkable genetic variation in observable traits such as morphology and phenology. In contrast to Great Lakes populations, however, relatively little is known about phytochemical variation in western aspen.

Genotypic variation rather than ploidy level determines functional trait expression in a foundation tree species in the presence and absence of environmental stress.

Background And Aims: At the population level, genetic diversity is a key determinant of a tree species' capacity to cope with stress. However, little is known about the relative importance of the different components of genetic diversity for tree stress responses. We compared how two sources of genetic diversity, genotype and cytotype (i.

Polyploidy and growth-defense tradeoffs in natural populations of western quaking Aspen.

Polyploidy, the expression of more than two sets of chromosomes, is common in plants, and is thought to influence plant trait expression and drive plant species evolution. The degree to which polyploidy influences interactions among physiological processes such as growth and defense in natural populations through its effect on phenotypic variability is poorly understood. We link broad plant genotypic features (including polyploidy) to phenotypic expression of growth and chemical defense in natural populations of quaking aspen (Populus tremuloides) to examine patterns in resource allocation that might drive growth-defense tradeoffs.

Remote sensing of cytotype and its consequences for canopy damage in quaking aspen.

Mapping geographic mosaics of genetic variation and their consequences via genotype x environment interactions at large extents and high resolution has been limited by the scalability of DNA sequencing. Here, we address this challenge for cytotype (chromosome copy number) variation in quaking aspen, a drought-impacted foundation tree species. We integrate airborne imaging spectroscopy data with ground-based DNA sequencing data and canopy damage data in 391 km of southwestern Colorado.

Cytotype and genotype predict mortality and recruitment in Colorado quaking aspen (Populus tremuloides).

Species responses to climate change depend on environment, genetics, and interactions among these factors. Intraspecific cytotype (ploidy level) variation is a common type of genetic variation in many species. However, the importance of intraspecific cytotype variation in determining demography across environments is poorly known.

Genotyping-by-sequencing and ecological niche modeling illuminate phylogeography, admixture, and Pleistocene range dynamics in quaking aspen ().

is the widest-ranging tree species in North America and an ecologically important component of mesic forest ecosystems displaced by the Pleistocene glaciations. Using phylogeographic analyses of genome-wide SNPs (34,796 SNPs, 183 individuals) and ecological niche modeling, we inferred population structure, ploidy levels, admixture, and Pleistocene range dynamics of , and tested several historical biogeographical hypotheses. We found three genetic lineages located mainly in coastal-Cascades (cluster 1), east-slope Cascades-Sierra Nevadas-Northern Rockies (cluster 2), and U.

Low offspring survival in mountain pine beetle infesting the resistant Great Basin bristlecone pine supports the preference-performance hypothesis.

The preference-performance hypothesis states that ovipositing phytophagous insects will select host plants that are well-suited for their offspring and avoid host plants that do not support offspring performance (survival, development and fitness). The mountain pine beetle (Dendroctonus ponderosae), a native insect herbivore in western North America, can successfully attack and reproduce in most species of Pinus throughout its native range. However, mountain pine beetles avoid attacking Great Basin bristlecone pine (Pinus longaeva), despite recent climate-driven increases in mountain pine beetle populations at the high elevations where Great Basin bristlecone pine grows.

Repurposing environmental DNA samples-detecting the western pearlshell () as a proof of concept.

Information on the distribution of multiple species in a common landscape is fundamental to effective conservation and management. However, distribution data are expensive to obtain and often limited to high-profile species in a system. A recently developed technique, environmental DNA (eDNA) sampling, has been shown to be more sensitive than traditional detection methods for many aquatic species.

Reproductive isolation and environmental adaptation shape the phylogeography of mountain pine beetle (Dendroctonus ponderosae).

Chromosomal rearrangement can be an important mechanism driving population differentiation and incipient speciation. In the mountain pine beetle (MPB, Dendroctonus ponderosae), deletions on the Y chromosome that are polymorphic among populations are associated with reproductive incompatibility. Here, we used RAD sequencing across the entire MPB range in western North America to reveal the extent of the phylogeographic differences between Y haplotypes compared to autosomal and X-linked loci.

Detection of individual ploidy levels with genotyping-by-sequencing (GBS) analysis.

Ploidy levels sometimes vary among individuals or populations, particularly in plants. When such variation exists, accurate determination of cytotype can inform studies of ecology or trait variation and is required for population genetic analyses. Here, we propose and evaluate a statistical approach for distinguishing low-level ploidy variants (e.

Phylogeny of the most species-rich freshwater bivalve family (Bivalvia: Unionida: Unionidae): Defining modern subfamilies and tribes.

Freshwater mussels of the order Unionida are key elements of freshwater habitats and are responsible for important ecological functions and services. Unfortunately, these bivalves are among the most threatened freshwater taxa in the world. However, conservation planning and management are hindered by taxonomic problems and a lack of detailed ecological data.

Defense traits in the long-lived Great Basin bristlecone pine and resistance to the native herbivore mountain pine beetle.

Mountain pine beetle (MPB, Dendroctonus ponderosae) is a significant mortality agent of Pinus, and climate-driven range expansion is occurring. Pinus defenses in recently invaded areas, including high elevations, are predicted to be lower than in areas with longer term MPB presence. MPB was recently observed in high-elevation forests of the Great Basin (GB) region, North America.

Genotyping-by-sequencing for Populus population genomics: an assessment of genome sampling patterns and filtering approaches.

Continuing advances in nucleotide sequencing technology are inspiring a suite of genomic approaches in studies of natural populations. Researchers are faced with data management and analytical scales that are increasing by orders of magnitude. With such dramatic advances comes a need to understand biases and error rates, which can be propagated and magnified in large-scale data acquisition and processing.

Imaging spectroscopy links aspen genotype with below-ground processes at landscape scales.

Fine-scale biodiversity is increasingly recognized as important to ecosystem-level processes. Remote sensing technologies have great potential to estimate both biodiversity and ecosystem function over large spatial scales. Here, we demonstrate the capacity of imaging spectroscopy to discriminate among genotypes of Populus tremuloides (trembling aspen), one of the most genetically diverse and widespread forest species in North America.

Widespread triploidy in Western North American aspen (Populus tremuloides).

We document high rates of triploidy in aspen (Populus tremuloides) across the western USA (up to 69% of genets), and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species), climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our evidence suggests that these phenomena are unlikely to be significant contributors to our observed patterns.

Spatial genetic structure of the mountain pine beetle (Dendroctonus ponderosae) outbreak in western Canada: historical patterns and contemporary dispersal.

Environmental change has a wide range of ecological consequences, including species extinction and range expansion. Many studies have shown that insect species respond rapidly to climatic change. A mountain pine beetle epidemic of record size in North America has led to unprecedented mortality of lodgepole pine, and a significant range expansion to the northeast of its historic range.

Genetic structuring in the freshwater mussel Anodonta corresponds with major hydrologic basins in the western United States.

Freshwater mussels (unionids) are increasingly recognized as important providers of ecosystem services, yet are among the most endangered fauna in the world. Because unionids are generally sessile and require specific fish hosts for development and dispersal, they are particularly vulnerable to habitat degradation. Surprisingly, little is known about the distribution of genetic diversity in freshwater mussels and this gap has a negative impact on taxonomy, monitoring, conservation and ecological research in these species.

Isolation and characterization of microsatellite loci in the western pearlshell mussel, Margaritifera falcata (Gould).

Ten microsatellite loci were isolated from the western pearlshell, Margaritifera falcata (Gould, 1850) and characterized in populations from Washington and Montana, USA. We also assessed eight microsatellite loci developed in M. margaritifera, two of which showed utility.

Isolation and characterization of microsatellite loci in western North American Anodonta species.

We have developed and characterized 13 microsatellite loci from a group of Anodonta species in western North America, and demonstrated their utility in populations representing two major clades in this genus. Allelic diversity and polymorphic information content were high for all loci, although these characteristics varied across populations. Deviations from Hardy-Weinberg genotypic ratios were not detected, although the estimated frequency of null alleles was high in one population for one locus.

Isolation of microsatellite loci from the coqui frog, Eleutherodactylus coqui.

Thirteen microsatellite loci were isolated from the coqui frog (Eleutherodactylus coqui) and optimized for future research. The loci were screened across 37 individuals from two Puerto Rican populations. Loci were variable with the number of alleles per locus ranging from three to 38.