Giant Sequoia Biogeography (original) (raw)
Related papers
2017
During this century, climate warming and altered precipitation patterns will lead to habitat changes that may be beneficial to some long-lived tree species and detrimental to others. Paleoendemics, with limited and disjunct distributions will face the greatest challenges, as migration rates will be too slow to keep pace with rapid environmental change and populations at the receding edges are eroded through mal-adaption. Giant sequoia (Sequoiadendron giganteum (Lindl.) Buchholz) is an iconic Sierra Nevada tree species with populations that tend to be small and highly fragmented (particularly in the northern range), making them especially vulnerable to environmental change. Maintenance of genetic variation is an important determinant of population persistence that, in part, depends on gene flow within and between populations. The research presented here describes: 1) the distribution of genetic diversity among population pairs distributed across the range of giant sequoia, and 2) the...
Ecology and evolution, 2016
Mediterranean ecosystems comprise a high proportion of endemic taxa whose response to climate change will depend on their evolutionary origins. In the California flora, relatively little attention has been given to the evolutionary history of paleoendemics from a molecular perspective, yet they number among some of the world's most iconic plant species. Here, we address questions of demographic change in Sequoiadendron giganteum (giant sequoia) that is restricted to a narrow belt of groves in the Sierra Nevada Mountains. We ask whether the current distribution is a result of northward colonization since the last glacial maximum (LGM), restriction of a broader range in the recent past (LGM) or independent colonizations in the deeper past. Genetic diversity at eleven microsatellite loci decreased with increasing latitude, but partial regressions suggested this was a function of smaller population sizes in the north. Disjunct populations north of the Kings River were divergent from...
A Reference Genome Sequence for Giant Sequoia
G3 Genes|Genomes|Genetics
The giant sequoia (Sequoiadendron giganteum) of California are massive, long-lived trees that grow along the U.S. Sierra Nevada mountains. Genomic data are limited in giant sequoia and producing a reference genome sequence has been an important goal to allow marker development for restoration and management. Using deep-coverage Illumina and Oxford Nanopore sequencing, combined with Dovetail chromosome conformation capture libraries, the genome was assembled into eleven chromosome-scale scaffolds containing 8.125 Gbp of sequence. Iso-Seq transcripts, assembled from three distinct tissues, was used as evidence to annotate a total of 41,632 protein-coding genes. The genome was found to contain, distributed unevenly across all 11 chromosomes and in 63 orthogroups, over 900 complete or partial predicted NLR genes, of which 375 are supported by annotation derived from protein evidence and gene modeling. This giant sequoia reference genome sequence represents the first genome sequenced in ...
2015
1. Is genetic diversity at neutral markers partitioned evenly among populations of giant sequoia? If so, does the architecture of diversity follow the common model for long-lived outcrossing woody species in which most genetic diversity is held within populations and population differentiation is low. The consequences of such a genetic architecture are that conservation strategies can be focused at the level of the species and not of individual populations. Hypothesis: Due to small population sizes, particularly in the northern range of giant sequoia, genetic diversity has been lost and populations have diverged through the stochastic effects of genetic drift. 2. Is there evidence of deep lineage divergence among populations consistent with long separation of population lineages, or is divergence among populations low suggesting that contemporary populations are the result of colonization from single source populations? If divergence is deep, this would suggest that different lineag...
The American Midland Naturalist, 2011
We developed a suite of tetranucleotide microsatellite loci and applied them to a study of genetic variation across the geographic range of coast redwood [Sequoia sempervirens (D. Don) Endl.]. The objectives of the study were to determine if the microsatellite loci could provide useful information on genetic diversity in this hexaploid species and to investigate earlier reports of divergent lineages within coast redwood. The microsatellite loci were highly variable, yielding a total of 142 alleles. Up to six alleles were detected in each individual consistent with the ploidy of coast redwood and suggesting that parental genomes must have been at least partially homologous. This does not rule out autoployploidy in the evolution of the redwood genome. We treated the microsatellite alleles as presence-absence data and we also estimated full genotypes assuming peak intensities varied with allele dosage. Both types of analyses revealed similar trends. Variation within the 17 watersheds sampled, explained most of the genetic diversity, with less than 4% of the variation attributable to watersheds. Our data showed a weak divergence between more or less continuous populations north of 36.8uN (the Sonoma-Mendocino county border) and disjunct populations south of this latitude. This is further north than indicated from earlier studies of marker systems that would be under selection and may reflect a demographic break. In view of the importance of clonal growth, we suggest that redwood may have difficulty adapting to new climatic conditions or of migrating into displaced habitats with anticipated climate change. Furthermore, the southern lineage of populations is likely to be at greatest risk and is therefore of conservation priority.
Forests
Research Highlights: Patterns of dispersal shape the distribution and temporal development of genetic diversity both within and among populations. In an era of unprecedented environmental change, the maintenance of extant genetic diversity is crucial to population persistence. Background and Objectives: We investigate patterns of pollen dispersal and spatial genetic structure within populations of giant sequoia (Sequoiadendron giganteum). Materials and Methods: The leaf genotypes of established trees from twelve populations were used to estimate the extent of spatial genetic structure within populations, as measured by the Sp statistic. We utilized progeny arrays from five populations to estimate mating parameters, the diversity of the pollen pool, and characteristics of pollen dispersal. Results: Our research indicates that giant sequoia is predominantly outcrossing, but exhibits moderate levels of bi-parental inbreeding (0.155). The diversity of the pollen pool is low, with an ave...
2015
Whereas polyploidy is common and an important evolutionary factor in most land plant lineages it is a real rarity in gymnosperms. Coast redwood (Sequoia sempervirens) is the only hexaploid conifer and one of just two naturally polyploid conifer species. Numerous hypotheses about the mechanism of polyploidy in Sequoia and parental genome donors have been proffered over the years, primarily based on morphological and cytological data, but it remains unclear how Sequoia became polyploid and why this lineage overcame an apparent gymnosperm barrier to whole-genome duplication (WGD). We sequenced transcriptomes and used phylogenetic inference, Bayesian concordance analysis, and paralog age distributions to resolve relationships among gene copies in hexaploid coast redwood and its close relatives. Our data show that hexaploidy in the coast redwood lineage is best explained by autopolyploidy or, if there was allopolyploidy, this was restricted to within the Californian redwood clade. We fou...
PLOS ONE, 2020
Coast redwood (Sequoia sempervirens) naturally growing in southern Oregon and northern California is one of the few conifer tree species that are polyploid. Despite its unique ecological and economic importance, its population genetic structure is still insufficiently studied. To obtain additional data on its population genetic structure we genotyped 317 samples collected from populations in California (data set C) and 144 trees growing in a provenance trial in France (data set F) using 12 nuclear (five random nuclear genomic nSSRs and seven expressed sequence tag EST-SSRs) and six chloroplast (cpSSRs) microsatellite or simple sequence repeat (SSR) markers, respectively. These data sets were also used as reference to infer the origin of 147 coast redwood trees growing in Germany (data set G). Coast redwood was introduced to Europe, including Germany as an ornamental species, decades ago. Due to its fast growth and high timber quality, it could be considered as a potential commercial...
Microsatellite markers in coast redwood (Sequoia sempervirens)
Molecular Ecology Notes, 2004
Five polymorphic microsatellite markers are described for coast redwood, a hexaploid conifer. Dinucleotide (three), trinucleotide (one) and tetranucleotide (one) repeat loci were isolated from a genomic plasmid library and amplified in a test population of 25 secondgrowth redwoods. There were three to 11 alleles per locus and observed heterozygosities ranged from 0.00 to 0.80. The nonheterozygous locus (a CTTA repeat) is probably of chloroplast origin and may have potential as a marker for paternal inheritance.