The genomes of Darwin's primroses reveal chromosome-scale adaptive introgression and differential permeability of species boundaries.

Introgression is an important source of genetic variation that can determine species adaptation to environmental conditions. Yet, definitive evidence of the genomic and adaptive implications of introgression in nature remains scarce. The widespread hybrid zones of Darwin's primroses (Primula elatior, Primula veris, and Primula vulgaris) provide a unique natural laboratory for studying introgression in flowering plants and the varying permeability of species boundaries. Through analysis of 650 genomes, we provide evidence of an introgressed genomic region likely to confer adaptive advantage in conditions of soil toxicity. We also document unequivocal evidence of chloroplast introgression, an important precursor to species-wide chloroplast capture. Finally, we provide the first evidence that the S-locus supergene, which controls heterostyly in primroses, does not introgress in this clade. Our results contribute novel insights into the adaptive role of introgression and demonstrate the importance of extensive genomic and geographical sampling for illuminating the complex nature of species boundaries.

Effectiveness of Communication Strategies in the Management of Chronic Postsurgical Pain: Protocol for a Systematic Review and Meta-Analysis.

Purpose: To describe the details of a systematic review to assess the current evidence about the efficacy of communication strategies on the prevention of chronic postsurgical pain (CPSP). Methods: The protocol for this systematic review was based on the Cochrane Handbook methodology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) recommendations. A systematic search of the literature on electronic databases Medline, Embase, Cochrane Library, CINAHL, PsycINFO, and Web of Science (from the inception to 19 June 2022) was carried out using predefined search terms to identify relevant studies. This review will include randomized clinical trials or observational studies. The search strategy consisted of keywords and index terms related to "clinician", "communication" or "post-surgical pain". Inclusion criteria are as follows: randomized clinical trials or observational studies using a parallel group design that assess the efficacy of communication interventions in patients undergoing surgery and that assess pain and pain-related disability. We considered interventions that included any type of written, verbal, and non-verbal communication in combination with other interventions or without. Control groups may include no communication intervention or another intervention distinctly different. We excluded studies with follow-up duration of less than 3 months, patients aged <18 years, and studies for which no reviewer had language proficiency (eg, Chinese, Korean). Descriptive statistics will be used to summarize quantitative findings. Meta-analysis will only be considered if at least three studies used the same outcome with comparable interventions, as we expect a wide heterogeneity of study population and settings. Conclusion: This systematic review and meta-analysis will be an important source for clinicians and researchers to understand the influence of communication to prevent CPSP. Study Registration: This protocol is registered with the International Prospective Register of Systematic Reviews (PROSPERO). Registration number: CRD42021241596.

Dynamics of the Negative Discourse Toward COVID-19 Vaccines: Topic Modeling Study and an Annotated Data Set of Twitter Posts.

BACKGROUND: Since the onset of the COVID-19 pandemic, vaccines have been an important topic in public discourse. The discussions around vaccines are polarized, as some see them as an important measure to end the pandemic, and others are hesitant or find them harmful. A substantial portion of these discussions occurs openly on social media platforms. This allows us to closely monitor the opinions of different groups and their changes over time. OBJECTIVE: This study investigated posts related to COVID-19 vaccines on Twitter (Twitter Inc) and focused on those that had a negative stance toward vaccines. It examined the evolution of the percentage of negative tweets over time. It also examined the different topics discussed in these tweets to understand the concerns and discussion points of those holding a negative stance toward the vaccines. METHODS: A data set of 16,713,238 English tweets related to COVID-19 vaccines was collected, covering the period from March 1, 2020, to July 31, 2021. We used the scikit-learn Python library to apply a support vector machine classifier to identify the tweets with a negative stance toward COVID-19 vaccines. A total of 5163 tweets were used to train the classifier, of which a subset of 2484 tweets was manually annotated by us and made publicly available along with this paper. We used the BERTopic model to extract the topics discussed within the negative tweets and investigate them, including how they changed over time. RESULTS: We showed that the negativity with respect to COVID-19 vaccines has decreased over time along with the vaccine rollouts. We identified 37 topics of discussion and presented their respective importance over time. We showed that popular topics not only consisted of conspiratorial discussions, such as 5G towers and microchips, but also contained legitimate concerns around vaccination safety and side effects as well as concerns about policies. The most prevalent topic among vaccine-hesitant tweets was related to the use of messenger RNA and fears about its speculated negative effects on our DNA. CONCLUSIONS: Hesitancy toward vaccines existed before the COVID-19 pandemic. However, given the dimension of and circumstances surrounding the COVID-19 pandemic, some new areas of hesitancy and negativity toward COVID-19 vaccines have arisen, for example, whether there has been enough time for them to be properly tested. There is also an unprecedented number of conspiracy theories associated with them. Our study shows that even unpopular opinions or conspiracy theories can become widespread when paired with a widely popular discussion topic such as COVID-19 vaccines. Understanding the concerns, the discussed topics, and how they change over time is essential for policy makers and public health authorities to provide better in-time information and policies to facilitate the vaccination of the population in future similar crises.

Investigation and response to a large outbreak of leptospirosis in field workers in Lower Saxony, Germany.

Between June and August 2014, 45 cases of leptospirosis were notified among workers on two strawberry farms in North-West Germany. We describe the characteristics of the outbreak and the actions taken to prevent further cases. The activities of the local, federal and national public health and veterinary authorities included collection of case data, laboratory testing of human specimens and of small mammals trapped on the fields, investigation of weather data, as well as information provided to farmers, field workers, physicians and to the authorities in Poland and Romania. Of the 45 identified cases (median age 22, 60% male), 47% were hospitalized. Characteristic symptoms were fever ≥38.5°C, generalized muscle pain and an increase in renal or liver enzymes. Thirteen cases were laboratory confirmed by serological and/or molecular methods. ELISA tests for Leptospira IgG and IgM-antibodies were positive in those samples taken >5 days after hospitalization. The probable causative agent was identified as Leptospira kirschneri serovar Grippotyphosa. Leptospira-specific DNA was found in kidneys of 67% of 64 trapped small mammals and was further identified as Leptospira kirschneri multi locus sequence type 110. During the estimated time period of human infections, the affected region faced warm weather with heavy rainfalls. The results of this investigation are in accordance with the theory of a chain of infection from mice to field workers during warm and humid weather. In 2015, a campaign was initiated to inform physicians, farmers and workers to enhance prevention measures, such as the use of personal protective equipment and early consultation of physicians in case of illness. Since then, no further outbreak occurred.

Whole-genome analyses disentangle reticulate evolution of primroses in a biodiversity hotspot.

Biodiversity hotspots, such as the Caucasus mountains, provide unprecedented opportunities for understanding the evolutionary processes that shape species diversity and richness. Therefore, we investigated the evolution of Primula sect. Primula, a clade with a high degree of endemism in the Caucasus. We performed phylogenetic and network analyses of whole-genome resequencing data from the entire nuclear genome, the entire chloroplast genome, and the entire heterostyly supergene. The different characteristics of the genomic partitions and the resulting phylogenetic incongruences enabled us to disentangle evolutionary histories resulting from tokogenetic vs cladogenetic processes. We provide the first phylogeny inferred from the heterostyly supergene that includes all species of Primula sect. Primula. Our results identified recurrent admixture at deep nodes between lineages in the Caucasus as the cause of non-monophyly in Primula. Biogeographic analyses support the 'out-of-the-Caucasus' hypothesis, emphasizing the importance of this hotspot as a cradle for biodiversity. Our findings provide novel insights into causal processes of phylogenetic discordance, demonstrating that genome-wide analyses from partitions with contrasting genetic characteristics and broad geographic sampling are crucial for disentangling the diversification of species-rich clades in biodiversity hotspots.

Different molecular changes underlie the same phenotypic transition: Origins and consequences of independent shifts to homostyly within species.

The repeated transition from outcrossing to selfing is a key topic in evolutionary biology. However, the molecular basis of such shifts has been rarely examined due to lack of knowledge of the genes controlling these transitions. A classic example of mating system transition is the repeated shift from heterostyly to homostyly. Occurring in 28 angiosperm families, heterostyly is characterized by the reciprocal position of male and female sexual organs in two (or three) distinct, usually self-incompatible floral morphs. Conversely, homostyly is characterized by a single, self-compatible floral morph with reduced separation of male and female organs, facilitating selfing. Here, we investigate the origins of homostyly in Primula vulgaris and its microevolutionary consequences by integrating surveys of the frequency of homostyles in natural populations, DNA sequence analyses of the gene controlling the position of female sexual organs (CYPᵀ), and microsatellite genotyping of both progeny arrays and natural populations characterized by varying frequencies of homostyles. As expected, we found that homostyles displace short-styled individuals, but long-style morphs are maintained at low frequencies within populations. We also demonstrated that homostyles repeatedly evolved from short-styled individuals in association with different types of loss-of-function mutations in CYPᵀ. Additionally, homostyly triggers a shift to selfing, promoting increased inbreeding within and genetic differentiation among populations. Our results elucidate the causes and consequences of repeated transitions to homostyly within species, and the putative mechanisms precluding its fixation in P. vulgaris. This study represents a benchmark for future analyses of losses of heterostyly in other angiosperms.

Physiological acclimation of elk during population restoration in the Missouri Ozarks, USA.

Conservation translocations-the intentional movement of animals to restore populations-have increased over the past 30 years to halt and reverse species declines and losses. However, there are many challenges translocated animals face that should be considered for restoration programs to be successful. Understanding how long it takes for translocated animals to acclimate to these challenges and their new landscape is a critical component of post-release population management. Physiological measures such as hormone responses are increasingly used to assess animal responses and acclimation to disturbances including translocation. We determined the physiological acclimation period of elk (Cervus canadensis) translocated to the Missouri Ozarks, USA, as part of a restoration effort. From 2011 to 2013, we translocated 108 GPS-radio-collared elk from Kentucky, USA, to Missouri, USA, and collected faecal samples for glucocorticoid metabolite extraction to use as an indicator of physiological acclimation. We modelled the response of population-wide faecal glucocorticoid metabolites (fGCMs) across the initial 9 years of the restoration in response to days following release and additional site-specific covariates. Presence of white-tailed deer (Odocoileus virginianus) hunts and monthly precipitation levels were positively and negatively associated with fGCM levels, respectively. Concurrent with influences from site-specific conditions on the release landscape, fGCM levels declined following release. We identified a breakpoint in fGCM decline at ~42 days following translocation releases suggesting elk acclimated physiologically relatively quickly compared to other species. The fast physiological acclimation by Missouri elk suggests effective use of temporary post-release management efforts. Determining how quickly animals acclimate following translocations allows researchers to tailor post-release management plans to each species' needs, thus maximizing the success of future translocation efforts while minimizing costs.

Comparative Genomics Elucidates the Origin of a Supergene Controlling Floral Heteromorphism.

Supergenes are nonrecombining genomic regions ensuring the coinheritance of multiple, coadapted genes. Despite the importance of supergenes in adaptation, little is known on how they originate. A classic example of supergene is the S locus controlling heterostyly, a floral heteromorphism occurring in 28 angiosperm families. In Primula, heterostyly is characterized by the cooccurrence of two complementary, self-incompatible floral morphs and is controlled by five genes clustered in the hemizygous, ca. 300-kb S locus. Here, we present the first chromosome-scale genome assembly of any heterostylous species, that of Primula veris (cowslip). By leveraging the high contiguity of the P. veris assembly and comparative genomic analyses, we demonstrated that the S-locus evolved via multiple, asynchronous gene duplications and independent gene translocations. Furthermore, we discovered a new whole-genome duplication in Ericales that is specific to the Primula lineage. We also propose a mechanism for the origin of S-locus hemizygosity via nonhomologous recombination involving the newly discovered two pairs of CFB genes flanking the S locus. Finally, we detected only weak signatures of degeneration in the S locus, as predicted for hemizygous supergenes. The present study provides a useful resource for future research addressing key questions on the evolution of supergenes in general and the S locus in particular: How do supergenes arise? What is the role of genome architecture in the evolution of complex adaptations? Is the molecular architecture of heterostyly supergenes across angiosperms similar to that of Primula?

A rare 300 kilometer dispersal by an adult male white-tailed deer.

Despite the key roles that dispersal plays in individual animal fitness and meta-population gene flow, it remains one of the least understood behaviors in many species. In large mammalian herbivores, dispersals might span long distances and thereby influence landscape-level ecological processes, such as infectious disease spread. Here, we describe and analyze an exceptional long-distance dispersal by an adult white-tailed deer (Odocoileus virginianus) in the central United States. We also conducted a literature survey to compare the dispersal to previous studies. This dispersal was remarkable for its length, duration, and the life history stage of the dispersing individual. Dispersal is typical of juvenile deer seeking to establish postnatal home ranges, but this dispersal was undertaken by an adult male (age = 3.5). This individual dispersed ~300 km over a 22-day period by moving, on average, 13.6 km/day and achieving a straight-line distance of ~215 km, which was ~174 km longer than any other distance recorded for an adult male deer in our literature survey. During the dispersal, which occurred during the hunting season, the individual crossed a major river seven times, an interstate highway, a railroad, and eight state highways. Movements during the dispersal were faster (mean = 568.1 m/h) and more directional than those during stationary home range periods before and after the dispersal (mean = 56.9 m/h). Likewise, movements during the dispersal were faster (mean = 847.8 m/h) and more directional at night than during the day (mean = 166.4 m/h), when the individual frequently sheltered in forest cover. This natural history event highlights the unpredictable nature of dispersal and has important implications for landscape-level processes such as chronic wasting disease transmission in cervids. More broadly, our study underscores how integrating natural history observations with modern technology holds promise for understanding potentially high impact but rarely recorded ecological events.

Asymmetries of reproductive isolation are reflected in directionalities of hybridization: integrative evidence on the complexity of species boundaries.

The complex nature of species boundaries has been a central topic in evolutionary biology ever since Darwin. Despite numerous separate studies on reproductive isolation and hybridization, their relationship remains underinvestigated. Are the strengths and asymmetries of reproductive barriers reflected in the extent and directionalities of interspecific genetic exchange? We combined field, experimental, and molecular data to quantify strengths and asymmetries of sympatric reproductive barriers and hybridization between florally heteromorphic primroses. We also assessed whether generalist pollinators discriminate between different floral cues and contribute to reproductive isolation, a long-debated topic. Sympatric reproductive isolation is high but incomplete, and most phenotypic intermediates are genetic F1 hybrids, whereas backcrosses are rare, revealing low interspecific gene flow. Species integrity rests on multiple barriers, but ethological isolation is among the strongest, demonstrating that even generalist pollinators crucially contribute to the maintenance of species boundaries. Furthermore, reproductive barriers are weaker for Primula veris and short-styled plants, results corroborated by molecular data. Thus, in florally heteromorphic systems, both species- and morph-dependent asymmetries affect permeability of species boundaries. Our study illustrates how the interactions between complex floral syndromes and pollinators shape species boundaries in unique, previously undescribed ways.

Supergene evolution via stepwise duplications and neofunctionalization of a floral-organ identity gene.

Heterostyly represents a fascinating adaptation to promote outbreeding in plants that evolved multiple times independently. While l-morph individuals form flowers with long styles, short anthers, and small pollen grains, S-morph individuals have flowers with short styles, long anthers, and large pollen grains. The difference between the morphs is controlled by an S-locus "supergene" consisting of several distinct genes that determine different traits of the syndrome and are held together, because recombination between them is suppressed. In Primula, the S locus is a roughly 300-kb hemizygous region containing five predicted genes. However, with one exception, their roles remain unclear, as does the evolutionary buildup of the S locus. Here we demonstrate that the MADS-box GLOBOSA2 (GLO2) gene at the S locus determines anther position. In Primula forbesii S-morph plants, GLO2 promotes growth by cell expansion in the fused tube of petals and stamen filaments beneath the anther insertion point; by contrast, neither pollen size nor male incompatibility is affected by GLO2 activity. The paralogue GLO1, from which GLO2 arose by duplication, has maintained the ancestral B-class function in specifying petal and stamen identity, indicating that GLO2 underwent neofunctionalization, likely at the level of the encoded protein. Genetic mapping and phylogenetic analysis indicate that the duplications giving rise to the style-length-determining gene CYP734A50 and to GLO2 occurred sequentially, with the CYP734A50 duplication likely the first. Together these results provide the most detailed insight into the assembly of a plant supergene yet and have important implications for the evolution of heterostyly.

Size matters: Sample size assessments for chronic wasting disease surveillance using an agent-based modeling framework.

Epidemiological surveillance for many important wildlife diseases relies on samples obtained from hunter-harvested animals. Statistical methods used to calculate sample size requirements assume that the target population is randomly sampled, and therefore the samples are representative of the population. But hunter-harvested samples may not be representative of the population due to disease distribution heterogeneities (e.g. spatial clustering of infected individuals), and harvest-related non-random processes like regulations, hunter selectivity, variable land access, and uneven hunter distribution. Consequently, sample sizes necessary for detection of disease are underestimated and disease detection probabilities are overestimated, resulting in erroneous inferences about disease presence and distribution. We have developed a modeling framework to support the design of efficient disease surveillance programs for wildlife populations. The constituent agent-based models can incorporate real-world heterogeneities associated with disease distribution, harvest, and harvest-based sampling, and can be used to determine population-specific sample sizes necessary for prompt detection of important wildlife diseases like chronic wasting disease and bovine tuberculosis. The modeling framework and its application has been described in detail by Belsare et al. [1]. Here we describe how model scenarios were developed and implemented, and how model outputs were analyzed. The main objectives of this methods paper are to provide users the opportunity to a) assess the reproducibility of the published model results, b) gain an in-depth understanding of model analysis, and c) facilitate adaptation of this modeling framework to other regions and other wildlife disease systems.•The two agent-based models, MOOvPOP and MOOvPOPsurveillance, incorporate real-world heterogeneities underpinned by host characteristics, disease spread dynamics, and sampling biases in hunter-harvested deer.•The modeling framework facilitates iterative analysis of locally relevant disease surveillance scenarios, thereby facilitating sample size calculations for prompt and reliable detection of important wildlife diseases.•Insights gained from modeling studies can be used to inform the design of effective wildlife disease surveillance strategies.

An agent-based framework for improving wildlife disease surveillance: A case study of chronic wasting disease in Missouri white-tailed deer.

Epidemiological surveillance for important wildlife diseases often relies on samples obtained from hunter-harvested animals. A problem, however, is that although convenient and cost-effective, hunter-harvest samples are not representative of the population due to heterogeneities in disease distribution and biased sampling. We developed an agent-based modeling framework that i) simulates a deer population in a user-generated landscape, and ii) uses a snapshot of the in silico deer population to simulate disease prevalence and distribution, harvest effort and sampling as per user-specified parameters. This framework can incorporate real-world heterogeneities in disease distribution, hunter harvest and harvest-based sampling, and therefore can be useful in informing wildlife disease surveillance strategies, specifically to determine population-specific sample sizes necessary for prompt detection of disease. Application of this framework is illustrated using the example of chronic wasting disease (CWD) surveillance in Missouri's white-tailed deer (Odocoileus virginianus) population. We show how confidence in detecting CWD is grossly overestimated under the unrealistic, but standard, assumptions that sampling effort and disease are randomly and independently distributed. We then provide adjusted sample size recommendations based on more realistic assumptions. Wildlife agencies can use these open-access models to design their CWD surveillance. Furthermore, these models can be readily adapted to other regions and other wildlife disease systems.

Selecting a Medical School Advisor.

Having an advisor offers medical students many advantages, including increased likelihood of matching into their top choices. Interestingly, students who choose emergency medicine (EM) as a specialty are more likely to seek advising. However, finding and optimally utilizing an EM faculty advisor is often challenging for the medical student. In this article, we tackle the different ways to seek advising, including the 'virtual advisor program' implemented by the Society for Academic Emergency Medicine, the 'e-Advisor Program' instigated by the Clerkship Director in EM Group, the 'member exclusive mentorship program' of the Emergency Medicine Residency Association, as well as peer-based mentoring. More so, we discuss the consensus recommendations developed by the Student Advising Task Force to guide both students planning to apply to EM and their advisors to ensure high-caliber advising.

Evaluating the individuality of animal-habitat relationships.

Examining the ways in which animals use habitat and select resources to satisfy their life history requirements has important implications for ecology, evolution, and conservation. The advent of radio-tracking in the mid-20th century greatly expanded the scope of animal-habitat modeling. Thereafter, it became common practice to aggregate telemetry data collected on a number of tagged individuals and fit one model describing resource selection at the population level. This convention, however, runs the risk of masking important individuality in the nature of associations between animals and their environment. Here, we investigated the importance of individual variation in animal-habitat relationships via the study of a highly gregarious species. We modeled elk (Cervus elaphus) location data, collected from Global Positioning System (GPS) collars, using Bayesian discrete choice resource selection function (RSF) models. Using a high-performance computing cluster, we batch-processed these models at the level of each individual elk (n = 88) and evaluated the output with respect to: (a) the composition of parameters in the most supported models, (b) the estimates of the parameters featured in the global models, and (c) spatial maps of the predicted relative probabilities of use. We detected considerable individual variation across all three metrics. For instance, the most supported models varied with respect to parameter composition with a range of seven to 17 and an average of 14.4 parameters per individual elk. The estimates of the parameters featured in the global models also varied greatly across individual elk with little conformity detected across age or sex classes. Finally, spatial mapping illustrated stark differences in the predicted relative probabilities of use across individual elk. Our analysis identifies that animal-habitat relationships, even among the most gregarious of species, can be highly variable. We discuss the implications of our results for ecology and present some guiding principles for the development of RSF models at the individual-animal level.

Creating Safe Spaces: A Community Health Worker-Academic Partnered Approach to Addressing Intimate Partner Violence.

Intimate partner violence (IPV) is a persistent public health problem in the United States, with an estimated one in three women experiencing rape, physical violence, and/or stalking by an intimate partner within her lifetime. Non-Hispanic Black women disproportionately experience IPV, but there has been limited success in implementing culturally appropriate prevention programs and services for members of this population. Community health workers (CHWs) are trusted members of under-resourced communities who provide reliable health information and improve the cultural appropriateness of service delivery and may be a vital resource for developing new IPV interventions. Guided by the principles of community partnered participatory research, we developed the CHW-led Safe Spaces project, which aimed to establish a strong academic-community partnership to focus on issues related to experiences of IPV and the prevention of IPV in New Orleans. In this article, we describe the development of our partnership including the formation of an advisory board, creation of a broad-based stakeholder coalition, offering a community partnered participatory research training, conducting IPV education and outreach, and establishing a research agenda. Our processes are replicable and lessons learned may be relevant to other groups seeking to address IPV by leveraging the strengths of community-academic collaborations and CHWs.

MENINGEAL WORM ( PARELAPHOSTRONGYLUS TENUIS) AS A CAUSE OF MORTALITY IN THE RESTORED ELK ( CERVUS CANADENSIS) POPULATION IN MISSOURI, USA.

: Meningeal worm ( Parelaphostrongylus tenuis) is an important cause of mortality of elk ( Cervus canadensis) in populations in the eastern US and has been implicated in the failure of several restoration attempts. From 2011 to 2013, the Missouri Department of Conservation translocated 108 adult and yearling elk from Kentucky (US) to southern Missouri (US) to establish a free-ranging population. From release in spring 2011 through August 2015, we monitored 167 elk (adult, yearling, and calf) to determine causes of mortality. Of 78 mortalities, 26 (33%) were linked to meningeal worm based on necropsy results and/or observed behavior; this group included 19 elk with confirmed or suspected cases of meningeal worm infection that died of other proximate causes. Other important mortality sources included euthanasia ( n=11, 14%), emaciation ( n=7, 9%), and predation ( n=5, 6%). Eleven of the 26 (42%) meningeal worm-related mortalities were adults, and 22 (85%) were female. Meningeal worm was an important cause of mortality during the restoration of Missouri elk, potentially contributing to the loss of 16% of the monitored individuals. Greater mortality in adult female elk could reduce initial population growth by limiting reproductive output in the restored herd, especially given that females were disproportionately affected in Missouri. Because translocated Missouri elk undoubtedly were exposed to meningeal worm in Kentucky, our results could be explained by exposure to a different genetic strain of meningeal worm once in Missouri, loss of immune response due to translocation, increased dose of larval worms, or some unquantified factor.

Parasites driving host diversity: Incidence of disease correlated with Daphnia clonal turnover.

According to the Red Queen hypothesis, clonal diversity in asexual populations could be maintained by negative frequency-dependant selection by coevolving parasites. If common clones are selected against and rare clones gain a concomitant advantage, we expect that clonal turnover should be faster during parasite epidemics than between them. We tested this hypothesis exploring field data of the Daphnia-Caullerya host-parasite system. The clonal make-up and turnover of the Daphnia host population was tracked with high temporal resolution from 1998 until 2013, using first allozyme and later microsatellite markers. Significant differences in the clonal composition between random and infected subsamples of Daphnia populations were detected on six of seven tested occasions, confirming genetic specificity of the host-parasite interaction in this system. We used time series analysis to compare the rates of host clonal turnover to the incidence of parasitism, and found that Caullerya prevalence was significantly associated with microsatellite-based clonal turnover. As alternate hypotheses, we further tested whether turnover was related to a variety of biotic, abiotic, and host demographic parameters. Other significant correlates of turnover were cyanobacterial biomass and (weakly) temperature. Overall, parasitism seems to be a strong driver of host clonal turnover, in support of the Red Queen hypothesis.

The measure and mismeasure of reciprocity in heterostylous flowers.

The goal of biological measurement is to capture underlying biological phenomena in numerical form. The reciprocity index applied to heterostylous flowers is meant to measure the degree of correspondence between fertile parts of opposite sex on complementary (inter-compatible) morphs, reflecting the correspondence of locations of pollen placement on, and stigma contact with, pollinators. Pollen of typical heterostylous flowers can achieve unimpeded fertilization only on opposite-morph flowers. Thus, the implicit goal of this measurement is to assess the likelihood of 'legitimate' pollinations between compatible morphs, and hence reproductive fitness. Previous reciprocity metrics fall short of this goal on both empirical and theoretical grounds. We propose a new measure of reciprocity based on theory that relates floral morphology to reproductive fitness. This method establishes a scale based on adaptive inaccuracy, a measure of the fitness cost of the deviation of phenotypes in a population from the optimal phenotype. Inaccuracy allows the estimation of independent contributions of maladaptive bias (mean departure from optimum) and imprecision (within-population variance) to the phenotypic mismatch (inaccuracy) of heterostylous morphs on a common scale. We illustrate this measure using data from three species of Primula (Primulaceae).

Presence versus absence of CYP734A50 underlies the style-length dimorphism in primroses.

Heterostyly is a wide-spread floral adaptation to promote outbreeding, yet its genetic basis and evolutionary origin remain poorly understood. In Primula (primroses), heterostyly is controlled by the S-locus supergene that determines the reciprocal arrangement of reproductive organs and incompatibility between the two morphs. However, the identities of the component genes remain unknown. Here, we identify the Primula CYP734A50 gene, encoding a putative brassinosteroid-degrading enzyme, as the G locus that determines the style-length dimorphism. CYP734A50 is only present on the short-styled S-morph haplotype, it is specifically expressed in S-morph styles, and its loss or inactivation leads to long styles. The gene arose by a duplication specific to the Primulaceae lineage and shows an accelerated rate of molecular evolution. Thus, our results provide a mechanistic explanation for the Primula style-length dimorphism and begin to shed light on the evolution of the S-locus as a prime model for a complex plant supergene.