Sclerocactus dawsoniae McGlaughlin & Naibauer (Cactaceae), a new species from western Colorado, is described. Sclerocactus dawsoniae is segregated from S. glaucus (K. Schum.) L. D. Benson, differing by having a smaller overall size, fewer spines per areole, an allopatric distribution, and substantial genetic differentiation.

IntroductionRecent advances in genetic data collection utilizing next-generation DNA sequencing technologies have the potential to greatly aid the taxonomic assessment of species of conservation concern, particularly species that have been difficult to describe using morphology alone. Accurate taxonomic descriptions aided by genetic data are essential to directing limited conservation resources to species most in need. Sclerocactus glaucus is a plant endemic to Western Colorado that is currently listed as Threatened under the Endangered Species Act (ESA). However, in 2023, the U. S. Fish and Wildlife Service proposed de-listing S. glaucus from the ESA due to recovery of the species. Previous research had found substantial genetic structure between populations in the northern part of the S. glaucus range relative to the majority of the species distribution.MethodsIn this study we utilized double-digest Restriction-site Associated DNA sequencing (RAD-seq) in order to better understand the genetic structure of S. glaucus.ResultsOur results indicate that S. glaucus contains two distinct evolutionary lineages that warrant recognition at the level of species, with what was previously described as S. glaucus North being recognized as Sclerocactus dawsoniae.DiscussionThe newly described S. dawsoniae has a limited estimated number of individuals, low levels of nucleotide diversity, a very narrow geographic range, and an uneven geographic distribution with most plants being found in a single management area, all of which supports continued direct conservation of this species. In contrast, S. glaucus has a large estimated minimum population size, a broad geographic range that includes numerous protected areas, and adequate levels of genetic diversity. Without further conservation action, a delisting decision for S. glaucus will simultaneously remove all Endangered Species Act protections for S. dawsoniae. The current work demonstrates the importance of having robust genetic datasets when planning conservation activities for species of concern. Moving forward, we recommend that government stakeholders prioritize supporting genetic studies of endangered species prior to making any changes to listing decisions.

Cannabis sativa L. is grown and marketed under a large number of named strains. Strains are often associated with phenotypic traits of interest to consumers, such as aroma and cannabinoid content. Yet genetic inconsistencies have been noted within named strains. We asked whether genetically inconsistent samples of a commercial strain also display inconsistent aroma profiles. We genotyped 32 samples using variable microsatellite regions to determine a consensus strain genotype and identify genetic outliers (if any) for four strains. Results were used to select 15 samples for olfactory testing. A genetic outlier sample was available for all but one strain. Aroma profiles were obtained by 55 sniff panelists using quantitative sensory evaluation of 40 odor descriptors. Within a strain, aroma descriptor frequencies for the genetic outlier were frequently at odds with those of the consensus samples. It appears that within-strain genetic differences are associated with differences in aroma profile. Because these differences were perceptible to untrained panelists, they may also be noticed by retail consumers. Our results could help the cannabis industry achieve better control of product consistency.

The National Institute on Drug Abuse (NIDA) is the sole producer of Cannabis for research purposes in the United States, including medical investigation. Previous research established that cannabinoid profiles in the NIDA varieties lacked diversity and potency relative to the Cannabis produced commercially. Additionally, microsatellite marker analyses have established that the NIDA varieties are genetically divergent form varieties produced in the private legal market. Here, we analyzed the genomes of multiple Cannabis varieties from diverse lineages including two produced by NIDA, and we provide further support that NIDA’s varieties differ from widely available medical, recreational, or industrial Cannabis . Furthermore, our results suggest that NIDA’s varieties lack diversity in the single-copy portion of the genome, the maternally inherited genomes, the cannabinoid genes, and in the repetitive content of the genome. Therefore, results based on NIDA’s varieties are not generalizable regarding the effects of Cannabis after consumption. For medical research to be relevant, material that is more widely used would have to be studied. Clearly, having research to date dominated by a single, non-representative source of Cannabis has hindered scientific investigation.

Currently in the United States, the sole licensed facility to cultivate Cannabis sativa L. for research purposes is the University of Mississippi, which is funded by the National Institute on Drug Abuse (NIDA). Studies researching Cannabis flower consumption rely on NIDA-supplied “research grade marijuana.” Previous research found that cannabinoid levels of NIDA-supplied Cannabis do not align with commercially available Cannabis. We sought to investigate the genetic identity of Cannabis supplied by NIDA relative to common categories within the species. This is the first genetic study to include “research grade marijuana” from NIDA. Samples (49) were assigned as Wild Hemp (feral; 6) and Cultivated Hemp (3), NIDA (2), CBD drug type (3), and high THC drug type subdivided into Sativa (11), Hybrid (14), and Indica (10). Ten microsatellites targeting neutral non-coding regions were used. Clustering and genetic distance analyses support a division between hemp and drug-type Cannabis. All hemp samples clustered genetically, but no clear distinction of Sativa, Hybrid, and Indica subcategories within retail marijuana samples was found. Interestingly, the two analyzed “research grade marijuana” samples obtained from NIDA were genetically distinct from most drug-type Cannabis available from retail dispensaries. Although the sample size was small, “research grade marijuana” provided for research is genetically distinct from most retail drug-type Cannabis that patients and patrons are consuming.

Public comfort with Cannabis (marijuana and hemp) has recently increased, resulting in previously strict Cannabis regulations now allowing hemp cultivation, medical use, and in some states, recreational consumption. There is a growing interest in the potential medical benefits of the various chemical constituents produced by the Cannabis plant. Currently, the University of Mississippi, funded through the National Institutes of Health/National Institute on Drug Abuse (NIH/NIDA), is the sole Drug Enforcement Agency (DEA) licensed facility to cultivate Cannabis for research purposes. Hence, most federally funded research where participants consume Cannabis for medicinal purposes relies on NIDA-supplied product. Previous research found that cannabinoid levels in research grade marijuana supplied by NIDA did not align with commercially available Cannabis from Colorado, Washington and California. Given NIDA chemotypes were misaligned with commercial Cannabis , we sought to investigate where NIDA’s research grade marijuana falls on the genetic spectrum of Cannabis groups. NIDA research grade marijuana was found to genetically group with Hemp samples along with a small subset of commercial drug-type Cannabis . A majority of commercially available drug-type Cannabis was genetically very distinct from NIDA samples. These results suggest that subjects consuming NIDA research grade marijuana may experience different effects than average consumers.

Abstract. The California Channel Islands are unique relative to other island chains due to their close proximity to the California mainland and the fact that individual islands, or groups of islands, vary in their distance to the mainland and other islands. This orientation raises questions about whether island taxa with widespread distributions form cohesive evolutionary units, or if they are actually composed of several distinct evolutionary entities, either derived from independent mainland-to-island colonization events or divergence due to prolonged allopatric isolation. The 4 northern islands are clustered in a line (6–8 km separation among islands), while the 4 southern islands are widely spaced (34–45 km separation among islands), which should impact the amount of gene flow and genetic connectivity among islands. We used nuclear microsatellite markers to examine the genetic structure and cohesion of 2 island shrubs, Acmispon dendroideus and A. argophyllus, which are widely distributed across the California Channel Islands. Both focal species contain varieties with multi-island distributions, with A. dendroideus exhibiting a greater distribution on the northern islands and A. argophyllus exhibiting a greater distribution on the southern islands. Substantial genetic divergence was observed for 2 single-island endemic varieties, A. dendroideus var. traskiae and A. agrophyllus var. niveus, confirming that allopatric isolation can lead to genetic divergence. The widespread Acmispon dendroideus var. dendroideus and single-island endemic A. dendroideus var. veatchii formed a cohesive evolutionary group that spans all 4 northern islands and 1 southern island, Santa Catalina, indicating that the northern and southern islands have been genetically linked in the past but do not display evidence of contemporary gene flow. In contrast, widespread A. argophyllus var. argenteus was composed of moderately distinct genetic groups on each of the 4 southern islands, with no evidence of recent gene flow among islands. These results demonstrate that isolation among islands has led to significant divergence among the southern islands, but that the commonly recognized split between northern and southern islands does not impact all taxa equally.

BACKGROUND:Unlike other plants, Cannabis sativa is excluded from regulation by the United States Department of Agriculture (USDA). Distinctive Cannabis varieties are ostracized from registration and therefore nearly impossible to verify. As Cannabis has become legal for medical and recreational consumption in many states, consumers have been exposed to a wave of novel Cannabis products with many distinctive names. Despite more than 2000 named strains being available to consumers, questions about the consistency of commercially available strains have not been investigated through scientific methodologies. As Cannabis legalization and consumption increases, the need to provide consumers with consistent products becomes more pressing. In this research, we examined commercially available, drug-type Cannabis strains using genetic methods to determine if the commonly referenced distinctions are supported and if samples with the same strain name are consistent when obtained from different facilities.METHODS:We developed ten de-novo microsatellite markers using the "Purple Kush" genome to investigate potential genetic variation within 30 strains obtained from dispensaries in three states. Samples were examined to determine if there is any genetic distinction separating the commonly referenced Sativa, Indica and Hybrid types and if there is consistent genetic identity found within strain accessions obtained from different facilities.RESULTS:Although there was strong statistical support dividing the samples into two genetic groups, the groups did not correspond to commonly reported Sativa/Hybrid/Indica types. The analyses revealed genetic inconsistencies within strains, with most strains containing at least one genetic outlier. However, after the removal of obvious outliers, many strains showed considerable genetic stability.CONCLUSIONS:We failed to find clear genetic support for commonly referenced Sativa, Indica and Hybrid types as described in online databases. Significant genetic differences within samples of the same strain were observed indicating that consumers could be provided inconsistent products. These differences have the potential to lead to phenotypic differences and unexpected effects, which could be surprising for the recreational user, but have more serious implications for patients relying on strains that alleviate specific medical symptoms.

Premise of the StudyClimate cycles of the Quaternary have impacted plants at a global scale, leaving behind a complex genetic legacy. Species of the northern Rocky Mountains of North America were exposed to more uniform glacial patterns than the central and southern ranges, where synergistic relationships between temperature and precipitation caused differences in the timing and extent of glacier onset. We examined the genetic impacts of climate oscillations on Calochortus gunnisonii (Liliaceae) in the central and southern Rocky Mountains. MethodsPopulations were sampled from disjunct mountain ranges across the basins of Wyoming and northern and central Colorado. Allelic data from nuclear microsatellites and plastid sequences (trnV-ndhC, petA-psbJ, and rpl16) were used to examine patterns of genetic structure between and among populations along the southern Rocky Mountain corridor. Key ResultsWe infer considerable population structure concordant with mountain range of origin. Clustering analysis supports separate north and south genetic clusters on either side of major basins in Wyoming, suggesting that populations were maintained in two distinct refugia. Additionally, populations within the Sierra Madre Range of southern Wyoming show localized, divergent genetic signal indicative of a third potential glacial refugium. By contrast, recent genetic admixture is observed in the Laramie, Medicine Bow, and Front ranges, where population expansion from glacial refugia has likely occurred. ConclusionsWe conclude that during climate cycles of the Quaternary, C. gunnisonii experienced periods of population expansion and reduction, habitat fragmentation, isolation in three or more refugia, and admixture mirroring genetic impacts of other southern Rocky Mountains organisms.

California Channel Island buckwheats are important components of scrub communities on the Channel Islands. A long history of overgrazing by introduced herbivores on San Clemente Island has contributed to scrub vegetation loss and population declines in 2 endemic island taxa, Eriogonum giganteum var. formosum and E. grande var. grande. Since herbivore removal, Eriogonum species, which are early colonizers of disturbed habitats, have been increasing across the island. These increases are thought to facilitate further recovery of the native flora because the shrubs act as nurse plants and improve the soil profile for other native species. We genotyped individuals from both taxa on San Clemente Island with 6-9 polymorphic microsatellite loci to estimate levels of genetic variability and structure and to detect any genetic impacts that could be attributable to demographic bottlenecks and subsequent early recoveries. Both taxa were characterized by low diversity across the island. Observed heterozygosities ranged from 0.021 to 0.337 ((x) over bar = 0.188), and most populations were fixed for a single allele at several loci. Additionally, Bayesian estimates of inbreeding were high (0.107-0.477;(x) over bar = 0.295) in most populations. Overall there was little evidence of genetic structure among E. grande var. grande sampling locations; we inferred 1-3 distinct genetic clusters within the taxon, depending on the analysis. In contrast, we inferred consistent genetic differentiation within E. giganteum var. forrnosurn, which generally has lower observed population sizes than E. grande var. grande. Both E. giganteum var. formosum and E. grande var. grande on San Clemente Island have low neutral genetic diversity compared to other island endemics, suggesting that the introduced herbivores contributed to the genetic effects of severe population bottlenecks and that the long-term viabilities of the taxa may be compromised by low genetic diversities. If this pattern is common among San Clemente Island native shrubs, more active management of the recovering populations may be warranted.

DNA barcoding is a simple technique used to develop a large-scale system of classification that is broadly applicable across a wide variety of taxa. DNA-based analysis of snake venoms can provide a system of classification independent of currently accepted taxonomic relationships by generating DNA barcodes specific to each venom sample. DNA purification from dried snake venoms has previously required large amounts of starting material, has resulted in low yields and inconsistent amplification, and was possible with front-fanged snakes only. Here, we present a modified DNA extraction protocol applied to venoms of both front- and rear-fanged snakes that requires significantly less starting material (1 mg) and yields sufficient amounts of DNA for successful PCR amplification of regions commonly used for DNA barcoding.

PREMISE OF THE STUDY:Taxa inhabiting the California Channel Islands exhibit variation in their degree of isolation, but few studies have considered patterns across the entire archipelago. We studied phylogeography of insular Acmispon argophyllus and A. dendroideus to determine whether infraspecific taxa are genetically divergent and to elucidate patterns of diversification across these islands.METHODS:DNA sequences were collected from nuclear (ADH) and plastid genomes (rpL16, ndhA, psbD-trnT) from >450 samples on the Channel Islands and California. We estimated population genetic diversity and structure, phylogenetic patterns among populations, and migration rates, and tested for population growth.KEY RESULTS:Populations of northern island A. argophyllus var. niveus are genetically distinct from conspecific populations on southern islands. On the southern islands, A. argophyllus var. argenteus populations on Santa Catalina are phylogenetically distinct from populations of var. argenteus and var. adsurgens on the other southern islands. For A. dendroideus, we found the varieties to be monophyletic. Populations of A. dendroideus var. traskiae on San Clemente are genetically differentiated from other conspecific populations, whereas populations on the northern islands and Santa Catalina show varying degrees of gene flow. Evidence of population growth was found in both species.CONCLUSIONS:Oceanic barriers between islands have had a strong influence on population genetic structure in both Acmispon species, although the species have differing phylogeographic patterns. This study provides a contrasting pattern of dispersal on a near island system that does not follow a strict stepping-stone model, commonly found on isolated island systems.

This study revisits the hypothesis that dispersal to California's Channel Islands follows a stepping-stone pattern from mainland California, based on earlier work indicating that the floras conform to classic island-biogeographic expectations. A re-examination of data incorporating the directions of prevailing and seasonal Santa Ana winds greatly strengthens the power of the model to explain levels of endemism in the Channel Island floras, and suggests the importance of aoelian processes for island colonization. Regression analysis of percent endemism in the native flora against distances measured along the axis of winds improves the r(2) from 0.099 to 0.482. The endemic species that flower in the dry season as a percent of the native flora of the islands is also strongly related to these revised source distances (r(2) = 0.665). Furthermore, the native floras of the southern islands are nested subsets of the floras of the northern islands, and angiosperm flowering peaks during the dry season, providing seed for seasonally based dispersal. These results suggest that the northern islands may have served as a source of colonists for the southern islands, and that the pattern of aeolian inputs into an island system should be considered in other plant biogeographic studies.

The relative roles of chance colonization and subsequent gene flow in the development of insular endemic biotas have been extensively studied in remote oceanic archipelagos, but are less well characterized on nearshore island systems. The current study investigated patterns of colonization and divergence between and within two wild buckwheat species (Polygonaceae), Eriogonum arborescens and E. giganteum, endemic to the California Channel Islands to determine whether geographical isolation is driving diversification. Using plastid and nuclear sequence data and microsatellite allele frequencies, we determined that gene flow in these Eriogonum spp. is restricted by isolation. The data suggest that successful colonization of and gene flow among the islands are infrequent. Colonization appears to have followed a stepping-stone model that is consistent with a north-to-south pattern across the islands. This colonization pattern coupled with relatively little post-colonization inter-island gene flow, particularly among southern islands, has generated a pattern of more divergent lineages on the isolated southern islands. These results run counter to the general expectation that all islands close to a continental source should receive a high level of gene flow. Finally, management recommendations focused on protecting the lineages from loss of private alleles and the erosion of the remaining genetic diversity are offered.

Natural interspecific hybridization within plants is relatively common and plays an important evolutionary role. Hybridization between rare and common taxa is of concern due to questions of protection status related to hybrids. However, field based identification of hybrid plants can be challenging. Sclerocactus glaucus (Cactaceae), the Colorado hookless cactus, is protected under the Endangered Species Act and has a small range around Grand Junction, Colorado, where populations are threatened by anthropogenic activities. Field biologists frequently observe S. glaucus populations containing individuals with hooked spines that are thought to be either hybrids or individuals of a closely related, parapatrically distributed species, Sclerocactus parviflorus. We used 13 nuclear microsatellites and two chloroplast DNA sequence regions to examine genetic diversity and structure within S. glaucus and potential hybridization with S. parviflorus. The two species were found to be genetically distinct based on microsatellites (average F-ST = 0.14 among species) and chloroplast sequence data (no shared haplotypes among species). Evidence of minimal hybridization was documented (5.7 % of sampled S. glaucus individuals with > 10 % S. parviflorus signal). Hybrid individuals did not show a clear geographic or morphological pattern. Sclerocactus glaucus populations contained significant genetic structure falling into north and south groups associated with two separate river drainages. Overall, genetic integrity of sampled S. glaucus populations is intact, with relatively high diversity (H-o = 0.47, H-e = 0.66) and low levels of inbreeding (F-IS = 0.28), indicating management should focus on protecting existing populations and preventing movement of material among genetically distinct regions.

PREMISE OF THE STUDY: Investigations of recently derived and edaphically (soil) defined plant systems have provided insight into important mechanisms of ecological divergence. We investigated the impact of edaphic adaptation on recent divergence between two Colorado Plateau endemics: the gypsum facultative Oreocarya revealii (Boraginaceae) and its more generalist sister species O. paradoxa. We assessed morphological stability, genetic identity, and soil chemistry to determine whether O. revealii is a distinct lineage edaphically adapted from O. paradoxa, as has been described in the literature.METHODS: We genotyped 21 populations throughout the ranges of both species using 11 microsatellite markers and three plastid regions (trnL-F, trnT-L, trnQ-rps16) for haplotype analysis. We compared these data with soil chemistry (Ca and S concentrations, indicating gypsum levels), location, and morphological identity of populations.KEY RESULTS: Soil chemistry failed to explain genetic or morphological identity in either taxon. Haplotype analysis suggests ancestral variation in the more geographically restricted O. revealii, along with regional geographic isolation. A discontinuity was identified between the morphological and genetic identity in several populations, suggesting incomplete lineage sorting and the nonfixation of identifying morphological traits.CONCLUSIONS: Oreocarya revealii is unlikely to have arisen via edaphic selection, because soil chemistry of population sites, morphology of individuals, and genetic identity are not strongly correlated. The nonfixation of identifying traits is likely a result of recent divergence in this system, and the potentiality of such discrepancies should be considered when investigating recently diversified gypsum-associated groups.

Premise of the study: Microsatellite primers were designed for Calochortus gunnisonii (Liliaceae), a montane lily species of the central and southern Rocky Mountains, using next-generation DNA sequencing. The markers will be used to investigate population structure, genetic diversity, and demographic history.Methods and Results: Thirteen polymorphic microsatellite loci were isolated from C. gunnisonii using Illumina MiSeq nextgeneration DNA sequencing and bioinformatic screening. The mean number of alleles per locus ranged from 4.15 to 5.92 (avg. = 4.97). Observed and expected heterozygosity ranged from 0.077 to 0.871 and 0.213 to 0.782, respectively. The primers were also tested for cross-species amplification value with C. flexuosus, C. nuttallii, C. kennedyi var. kennedyi, and C. subalpinus.Conclusions: These primers will be useful for genetic and evolutionary studies across C. gunnisonii's range within the southern and central Rocky Mountains. Furthermore, these markers have proven valuable for cross-species amplifications within Calochortus

Sibara filifolia (Brassicaceae), Santa Cruz Island Rock Cress, an endangered annual plant endemic to the California Channel Islands which was presumed extinct for nearly 50 years, is currently known from only a few small patches on San Clemente Island (SCl) and Santa Catalina Island (SCa). In addition to protecting extant populations, recovery efforts have included ex situ seed collections to hedge against stochastic population losses. We examined genetic diversity and population structure in the wild and the effect of sampling intensity on the genetic diversity of ex situ seed collections using 13 species-specific microsatellite loci. Much of the genetic variation on each island consisted of rare alleles; 33 % (SCl) or 56 % (SCa) of the non-fixed alleles occurred at frequencies ≤0.05. Patches on SCl were genetically depauperate (mean HO = 0.002) compared to patches on SCa (mean HO = 0.344). One patch on SCl was genetically distinct, while the remaining four patches were genetically indistinguishable. The three patches on SCa were genetically distinct from those on SCl, but not from one another. Simulated sampling for the ex situ seed collections found that 10 individuals was sufficient to capture 90 % of the diversity for normalized measures (NE, HO, and HE) in a depauperate (SCl) population, while 30 individuals was necessary in a diverse (SCa) population. However, sampling 125 (SCl) or 60 (SCa) individuals was necessary to capture 90 % of all the alleles present. These findings indicate that theoretical guidelines for ex situ seed collections that recommend targeting 50 individuals per population overestimate the sampling effort required to adequately preserve common alleles, but may underestimate the effort necessary to capture most alleles in wild populations.