Evolutionary walks through flower colour space driven by gene expression in Petunia and allies (Petunieae).

The structure and function of biochemical and developmental pathways determine the range of accessible phenotypes, which are the substrate for evolutionary change. Accordingly, we expect that observed phenotypic variation across species is strongly influenced by pathway structure, with different phenotypes arising due to changes in activity along pathway branches. Here, we use flower colour as a model to investigate how the structure of pigment pathways shapes the evolution of phenotypic diversity. We focus on the phenotypically diverse Petunieae clade in the nightshade family, which contains ca 180 species of Petunia and related genera, as a model to understand how flavonoid pathway gene expression maps onto pigment production. We use multivariate comparative methods to estimate co-expression relationships between pathway enzymes and transcriptional regulators, and then assess how expression of these genes relates to the major axes of variation in floral pigmentation. Our results indicate that coordinated shifts in gene expression predict transitions in both total anthocyanin levels and pigment type, which, in turn, incur trade-offs with the production of UV-absorbing flavonol compounds. These findings demonstrate that the intrinsic structure of the flavonoid pathway and its regulatory architecture underlies the accessibility of pigment phenotypes and shapes evolutionary outcomes for floral pigment production.

Genetic potential for changes in breeding systems: Predicted and observed trait changes during artificial selection for male and female allocation in a gynodioecious species.

PREMISE: Evolution of separate sexes from hermaphroditism often proceeds through gynodioecy, but genetic constraints on this process are poorly understood. Genetic (co-)variances and between-sex genetic correlations were used to predict evolutionary responses of multiple reproductive traits in a sexually dimorphic gynodioecious species, and predictions were compared with observed responses to artificial selection. METHODS: Schiedea (Caryophyllaceae) is an endemic Hawaiian lineage with hermaphroditic, gynodioecious, subdioecious, and dioecious species. We measured genetic parameters of Schiedea salicaria and used them to predict evolutionary responses of 18 traits in hermaphrodites and females in response to artificial selection for increased male (stamen) biomass in hermaphrodites or increased female (carpel, capsule) biomass in females. Observed responses over two generations were compared with predictions in replicate lines of treatments and controls. RESULTS: In only two generations, both stamen biomass in hermaphrodites and female biomass in females responded markedly to direct selection, supporting a key assumption of models for evolution of dioecy. Other biomass traits, pollen and ovule numbers, and inflorescence characters important in wind pollination evolved indirectly in response to selection on sex allocation. Responses generally followed predictions from multivariate selection models, with some responses unexpectedly large due to increased genetic correlations as selection proceeded. CONCLUSIONS: Results illustrate the power of artificial selection and utility of multivariate selection models incorporating sex differences. They further indicate that pollen and ovule numbers and inflorescence architecture could evolve in response to selection on biomass allocation to male versus female function, producing complex changes in plant phenotype as separate sexes evolve.

How to approach the study of syndromes in macroevolution and ecology.

Syndromes, wherein multiple traits evolve convergently in response to a shared selective driver, form a central concept in ecology and evolution. Recent work has questioned the existence of some classic syndromes, such as pollination and seed dispersal syndromes. Here, we discuss some of the major issues that have afflicted research into syndromes in macroevolution and ecology. First, correlated evolution of traits and hypothesized selective drivers is often relied on as the only evidence for adaptation of those traits to those hypothesized drivers, without supporting evidence. Second, the selective driver is often inferred from a combination of traits without explicit testing. Third, researchers often measure traits that are easy for humans to observe rather than measuring traits that are suited to testing the hypothesis of adaptation. Finally, species are often chosen for study because of their striking phenotypes, which leads to the illusion of syndromes and divergence. We argue that these issues can be avoided by combining studies of trait variation across entire clades or communities with explicit tests of adaptive hypotheses and that taking this approach will lead to a better understanding of syndrome-like evolution and its drivers.

Transcription Factors Evolve Faster Than Their Structural Gene Targets in the Flavonoid Pigment Pathway.

Dissecting the relationship between gene function and substitution rates is key to understanding genome-wide patterns of molecular evolution. Biochemical pathways provide powerful systems for investigating this relationship because the functional role of each gene is often well characterized. Here, we investigate the evolution of the flavonoid pigment pathway in the colorful Petunieae clade of the tomato family (Solanaceae). This pathway is broadly conserved in plants, both in terms of its structural elements and its MYB, basic helix-loop-helix, and WD40 transcriptional regulators, and its function has been extensively studied, particularly in model species of petunia. We built a phylotranscriptomic data set for 69 species of Petunieae to infer patterns of molecular evolution across pathway genes and across lineages. We found that transcription factors exhibit faster rates of molecular evolution (dN/dS) than their targets, with the highly specialized MYB genes evolving fastest. Using the largest comparative data set to date, we recovered little support for the hypothesis that upstream enzymes evolve slower than those occupying more downstream positions, although expression levels do predict molecular evolutionary rates. Although shifts in floral pigmentation were only weakly related to changes affecting coding regions, we found a strong relationship with the presence/absence patterns of MYB transcripts. Intensely pigmented species express all three main MYB anthocyanin activators in petals, whereas pale or white species express few or none. Our findings reinforce the notion that pathway regulators have a dynamic history, involving higher rates of molecular evolution than structural components, along with frequent changes in expression during color transitions.

Changing occupational roles for the young adult with cancer: A longitudinal case study.

INTRODUCTION: Young adulthood is a period of rapid occupational role development. While the impact of a cancer diagnosis at this time is likely to be substantial, little research has addressed this topic. The aims of this study were to gain insights into the impact of cancer on occupational roles throughout the cancer disease trajectory, from diagnosis to the palliative stage, for one young person. METHODS: A longitudinal case study design was used. Five semi-structured interviews, layered with photo elicitation, were conducted over 3 years. Qualitative data were analysed thematically. RESULTS: Three themes emerged: the adjusted plan, establishing rules, and damage control and self-preservation. Challenges impacting participation in, and meaning of, and the occupational roles themselves shifted over time. CONCLUSION: Findings provide knowledge of occupational adaptation, and the reconstruction of occupational role identity and participation, of the young adult living with cancer along the disease trajectory.

Occupational therapy in oncology palliative care for adolescents and young adults: Perspectives of Australian occupational therapists.

INTRODUCTION: Palliative Care Australia suggests current needs (emotional wellbeing, understanding of cancers impact on relationships, everyday activities, and life milestones) for adolescent and young adults in palliative care are unmet due to a lack of age-specific palliative care facilities in Australia. This includes the provision of occupational therapy that can impact these unmet needs. Although the occupational therapy role in palliative care has been documented, little is known about existing occupational therapy services or occupational needs for young people with palliative care needs. The aims of this study were to obtain occupational therapists insights of working with this population in Australia regarding (1) gaps in palliative care services for this population; (2) facilitators and challenges to providing occupational therapy for this group; and (3) perceived occupational needs of young people living with a life-limiting cancer diagnosis. METHODS: Using snowball sampling, an online survey was distributed to occupational therapists with experience working in palliative cancer care with adolescents and young adults. Available for 6 weeks, the survey included demographic, work history, and service delivery questions. Forced-choice questions were summarised descriptively, and content analysis was used to analyse free-text data. RESULTS: Eleven completed surveys were returned. Overall, therapists perceived current palliative care services for this population within Australia to be lacking. Two gaps emerged: age-appropriate facilities and gaps in provision of psycho-social and occupational therapy services. Funding, lack of knowledge of the occupational therapy role, and professional confidence were highlighted as challenges to practice. Main occupational needs related to maintenance of as "normal" a life as possible: maintaining occupational role engagement, continuing connection with others, and being heard regarding their occupational needs. CONCLUSION: Findings suggest a need for service changes, including custom-designed facilities, improved funding, training and mentoring, to support age-appropriate and occupation-focussed care for the young person in cancer-specific palliative care.

Occupational therapy intervention for cancer patients following hospital discharge: How and when should we intervene? A systematic review.

INTRODUCTION: Advances in cancer treatment over the last decade have led to increased survival rates. As a result, survivors are living longer with and beyond cancer, often with greater levels of morbidity. Occupational therapists, with their focus on remedial and compensatory strategies to improve function and participation, are well suited to assess and intervene with this population. Despite this, little research exists to demonstrate the efficacy of interventions and value of the occupational therapy role. This systematic review aimed to review how and when occupational therapists provide services for adult patients with cancer and identify where they add the most value. METHODS: A systematic search was conducted of six electronic databases. Eligible studies reported on occupational therapy interventions targeting management of cancer symptoms, rehabilitation or environmental modifications for adult cancer patients discharged from acute hospital services. Data extraction and quality assessment were undertaken by two reviewers. Narrative synthesis summarised the attributes and treatment outcomes of each intervention. RESULTS: Nine articles were included from a total of 309 articles retrieved. Eight different interventions were reported for people with cancer (n = 531). Small sample sizes and methodological quality precluded any formal analysis; however, intervention components that showed positive results were person-centred, individualised and included regular monitoring and flexibility in care, with input from multidisciplinary health professionals. Therapists also need to reflect upon the optimal duration of interventions and selection of outcome measures that specifically match intervention components. CONCLUSION: Despite inconclusive support of any particular type of intervention, this systematic review identified several successful intervention components for occupational therapists working with people with or beyond cancer. Overall, findings suggest that monitored tailored programmes compensating for fluctuations in a patient's condition have efficacy to improve patient outcomes and should be considered when delivering intervention with patients post hospital discharge.

Return to work and cancer: Perspectives of occupational therapists.

INTRODUCTION: Progress in the early detection, diagnosis, and treatment of cancer has translated into more people in Australia living with and beyond cancer. Therefore, there is a larger number of people returning to work following cancer treatment while managing ongoing symptoms of cancer, and side effects of treatment. The purpose of this study was to explore the facilitators and barriers for return to work for someone with cancer, from the perspective of occupational therapists. METHOD: This study used a qualitative descriptive design. Participants were recruited via key contacts within the industry and relevant interest groups, and included eight occupational therapists with experience supporting someone with cancer to return to work. Data were collected in semi-structured in-depth Interviews which were audio recorded, transcribed verbatim, and analysed thematically. FINDINGS: Two main themes were developed; expectations of the cancer experience versus reality, and vulnerability during return to work. Occupational therapists perceived that the person with cancer, employers, family members, co-workers, and society underestimate the impact of ongoing cancer symptoms on return to work. Return to work was challenging as survivors face unexpected challenges due to ongoing fatigue, cognitive difficulties, or psychological factors. Fear of relapse, concerns regarding disclosure affecting how people with cancer are perceived at work, and worries of leaving the high levels of professional support during treatment, also affected return to work. CONCLUSION: Findings from this study may contribute to occupational therapists and people with cancer setting realistic expectations for the return to work experience. Furthermore, it may provide support for occupational therapists to work more effectively with their clients to facilitate a smoother transition back to work as a cancer survivor.

Cancer care and occupational therapy: A scoping review.

INTRODUCTION: Cancer can disrupt participation in everyday activities, suggesting a place for occupational therapy; however, there is a need to articulate the nature, scope and available evidence supporting the occupational therapy role within cancer care. In this scoping review, we identify the breadth of practice and evidence for occupational therapy in cancer care, across all stages of the disease trajectory (diagnosis to palliation/survivorship) throughout the lifespan. METHODS: Five electronic databases were searched in June 2018, for English language articles. Key words were: cancer care, OR oncolog*, OR oncologic care, OR neoplasms, OR cancer survivors, OR terminal cancer, OR cancer rehabilitation, AND occupational therap*. No date restrictions were imposed. Included were: all styles of literature including grey literature, all types of cancers and all age brackets. There were no restrictions on place of origin of papers. Following the Arksey and O'Malley (2006; International Journal of Social Research Methodology, 8: 19-32) framework for scoping reviews, the first author screened titles and abstracts, and all three authors reviewed sets of the included articles. Conflicts were discussed until consensus was reached. RESULTS: After evaluating 305 titles and abstracts and 111 full-text articles, 89 papers were retained. Articles included research studies (n = 43), reviews (n = 15), grey literature (n = 16), practice analyses (n = 14) and an editorial (n = 1). The occupational therapy roles described were diverse, but largely descriptive in nature, with little evidence of outcomes from treatment. Furthermore, the majority of papers addressed adult populations, with few considering children, adolescents or young adults. Most papers focused on specific stages of the disease, and none addressed the disease along its full trajectory. CONCLUSION: Despite identifying a diverse range of occupational therapy roles in cancer care throughout the disease trajectory and across the lifespan, the need for professional discourse and research within our profession was highlighted. This was particularly evident for adolescents and young adults with cancer.

Developmental control of convergent floral pigmentation across evolutionary timescales.

BACKGROUND: Convergent phenotypic evolution has been widely documented across timescales, from populations, to species, to major lineages. The extent to which convergent phenotypes arise from convergent genetic and developmental mechanisms remains an open question, although studies to-date reveal examples of both similar and different underlying mechanisms. This variation likely relates to a range of factors, including the genetic architecture of the trait and selective filtering of mutations over time. Here we focus on floral pigmentation, and examine the degree of developmental convergence between white-flowered lineages and white morphs within pigmented species. RESULTS: Using the model clade Iochrominae, we find that white morphs and white-flowered species are biochemically convergent, sharing an absence of colorful anthocyanin pigments. Regression analyses suggest that the expression levels of upstream genes are the strongest drivers of total pigmentation across species, although white species also show sharp down-regulation of the downstream genes. The white morphs do not share this pattern and present overall expression profiles more similar to the pigmented species. CONCLUSIONS: These results suggest that the mechanisms underlying variation within populations differ from those which give rise to fixed differences between species. Future work will aim to uncover the genetic changes responsible for this developmental non-convergence.

Convergent Evolution at the Pathway Level: Predictable Regulatory Changes during Flower Color Transitions.

The predictability of evolution, or whether lineages repeatedly follow the same evolutionary trajectories during phenotypic convergence remains an open question of evolutionary biology. In this study, we investigate evolutionary convergence at the biochemical pathway level and test the predictability of evolution using floral anthocyanin pigmentation, a trait with a well-understood genetic and regulatory basis. We reconstructed the evolution of floral anthocyanin content across 28 species of the Andean clade Iochrominae (Solanaceae) and investigated how shifts in pigmentation are related to changes in expression of seven key anthocyanin pathway genes. We used phylogenetic multivariate analysis of gene expression to test for phenotypic and developmental convergence at a macroevolutionary scale. Our results show that the four independent losses of the ancestral pigment delphinidin involved convergent losses of expression of the three late pathway genes (F3'5'h, Dfr, and Ans). Transitions between pigment types affecting floral hue (e.g., blue to red) involve changes to the expression of branching genes F3'h and F3'5'h, while the expression levels of early steps of the pathway are strongly conserved in all species. These patterns support the idea that the macroevolution of floral pigmentation follows predictable evolutionary trajectories to reach convergent phenotype space, repeatedly involving regulatory changes. This is likely driven by constraints at the pathway level, such as pleiotropy and regulatory structure.

Correction to: Open-label pilot for treatment targeting gut dysbiosis in myalgic encephalomyelitis/chronic fatigue syndrome: neuropsychological symptoms and sex comparisons.

The original version of this article [1], published on 6 February 2018, contains a mistake in the 'Conclusions' section. The corrected version of the affected sentence is given below and the corrected part is marked in bold.

Open-label pilot for treatment targeting gut dysbiosis in myalgic encephalomyelitis/chronic fatigue syndrome: neuropsychological symptoms and sex comparisons.

BACKGROUND: Preliminary evidence suggests that the enteric microbiota may play a role in the expression of neurological symptoms in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Overlapping symptoms with the acute presentation of D-lactic acidosis has prompted the use of antibiotic treatment to target the overgrowth of species within the Streptococcus genus found in commensal enteric microbiota as a possible treatment for neurological symptoms in ME/CFS. METHODS: An open-label, repeated measures design was used to examine treatment efficacy and enable sex comparisons. Participants included 44 adult ME/CFS patients (27 females) from one specialist medical clinic with Streptococcus viable counts above 3.00 × 105 cfu/g (wet weight of faeces) and with a count greater than 5% of the total count of aerobic microorganisms. The 4-week treatment protocol included alternate weeks of Erythromycin (400 mg of erythromycin as ethyl succinate salt) twice daily and probiotic (D-lactate free multistrain probiotic, 5 × 1010 cfu twice daily). 2 × 2 repeated measures ANOVAs were used to assess sex-time interactions and effects across pre- and post-intervention for microbial, lactate and clinical outcomes. Ancillary non-parametric correlations were conducted to examine interactions between change in microbiota and clinical outcomes. RESULTS: Large treatment effects were observed for the intention-to-treat sample with a reduction in Streptococcus viable count and improvement on several clinical outcomes including total symptoms, some sleep (less awakenings, greater efficiency and quality) and cognitive symptoms (attention, processing speed, cognitive flexibility, story memory and verbal fluency). Mood, fatigue and urine D:L lactate ratio remained similar across time. Ancillary results infer that shifts in microbiota were associated with more of the variance in clinical changes for males compared with females. CONCLUSIONS: Results support the notion that specific microorganisms interact with some ME/CFS symptoms and offer promise for the therapeutic potential of targeting gut dysbiosis in this population. Streptococcus spp. are not the primary or sole producers of D-lactate. Further investigation of lactate concentrations are needed to elucidate any role of D-lactate in this population. Concurrent microbial shifts that may be associated with clinical improvement (i.e., increased Bacteroides and Bifidobacterium or decreased Clostridium in males) invite enquiry into alternative strategies for individualised treatment. Trial Registration Australian and New Zealand Clinical Trial Registry (ACTRN12614001077651) 9th October 2014. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=366933&isReview=true.

Examining clinical similarities between myalgic encephalomyelitis/chronic fatigue syndrome and D-lactic acidosis: a systematic review.

BACKGROUND: The pursuit for clarity in diagnostic and treatment pathways for the complex, chronic condition of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) continues. This systematic review raises a novel question to explore possible overlapping aetiology in two distinct conditions. Similar neurocognitive symptoms and evidence of D-lactate producing bacteria in ME/CFS raise questions about shared mechanisms with the acute condition of D-lactic acidosis (D-la). METHODS: D-la case reports published between 1965 and March 2016 were reviewed for episodes describing both neurological symptoms and high D-lactate levels. Fifty-nine D-la episodes were included in the qualitative synthesis comparing D-la symptoms with ME/CFS diagnostic criteria. A narrative review of D-la mechanisms and relevance for ME/CFS was provided. RESULTS: The majority of neurological disturbances reported in D-la episodes overlapped with ME/CFS symptoms. Of these, the most frequently reported D-la symptoms were motor disturbances that appear more prominent during severe presentations of ME/CFS. Both patient groups shared a history of gastrointestinal abnormalities and evidence of bacterial dysbiosis, although only preliminary evidence supported the role of lactate-producing bacteria in ME/CFS. LIMITATIONS: Interpretation of results are constrained by both the breadth of symptoms included in ME/CFS diagnostic criteria and the conservative methodology used for D-la symptom classification. Several pathophysiological mechanisms in ME/CFS were not examined. CONCLUSIONS: Shared symptomatology and underlying microbiota-gut-brain interactions raise the possibility of a continuum of acute (D-la) versus chronic (ME/CFS) presentations related to D-lactate absorption. Measurement of D-lactate in ME/CFS is needed to effectively evaluate whether subclinical D-lactate levels affect neurological symptoms in this clinical population.

Support for the microgenderome invites enquiry into sex differences.

The microgenderome defines the interaction between microbiota, sex hormones and the immune system. Our recent research inferred support for the microgenderome by showing sex differences in microbiota-symptom associations in a clinical sample of patients with myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS). This addendum expands upon the sex-specific pattern of associations that were observed. Interpretations are hypothesized in relation to genera versus species-level analyses and D-lactate theory. Evidence of sex-differences invites future research to consider sex comparisons in microbial function even when microbial abundance is statistically similar. Pairing assessment of clinical symptoms with microbial culture, DNA sequencing and metabolomics methods will help advance our current understandings of the role of the microbiome in health and disease.

Support for the Microgenderome: Associations in a Human Clinical Population.

The 'microgenderome' provides a paradigm shift that highlights the role of sex differences in the host-microbiota interaction relevant for autoimmune and neuro-immune conditions. Analysis of cross-sectional self-report and faecal microbial data from 274 patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) suggests that commensal gut microorganisms may play both protective and deleterious roles in symptom expression. Results revealed significant sex-specific interactions between Firmicutes (Clostridium, Streptococcus, Lactobacillus and Enterococcus) and ME/CFS symptoms (including neurological, immune and mood symptoms), regardless of compositional similarity in microbial levels across the sexes. Extending animal studies, we provide support for the microgenderome in a human clinical population. Applied and mechanistic research needs to consider sex-interactions when examining the composition and function of human microbiota.

Measure for measure: comparing morphological and biomass traits for sex allocation in two gynodioecious species.

PREMISE OF THE STUDY: Sex allocation models assume male and female traits are measured in a common currency, allocation traits show heritability, and tradeoffs between investment in the two sexual functions occur. The potential for model predictions and genetic parameters to depend on the currency used is not well understood, despite frequent use of measures not in a common currency. • METHODS: We analyzed the relationship between common currency (biomass of carpels, seeds, and stamens) measures and morphological measures (numbers of ovules, seeds, and pollen) in Schiedea salicaria (12-13% females) and S. adamantis (39% females), two closely related gynodioecious species. Additionally, we compared heritabilities and genetic correlations for male and female allocation between these two types of measures. • KEY RESULTS: Ovule, seed, and pollen number show greater sexual dimorphism in S. adamantis than in S. salicaria. Most but not all morphological traits and analogous biomass traits are highly correlated with a linear relationship. Narrow-sense heritabilities based on the two methods are often similar, but higher for ovule number than carpel mass and lower for anther number than stamen mass in S. adamantis. Neither trait type shows negative genetic correlations between male and female function. • CONCLUSIONS: Both trait types show greater sexual dimorphism in S. adamantis, and significant heritabilities suggest that morphological traits will continue to evolve with breeding system changes. Although most relationships between morphological and biomass traits are linear, curvilinear relationships for two traits suggest that caution is warranted if morphological and common currency traits are used interchangeably in fitness gain curves.

Genetic variation and covariation in floral allocation of two species of Schiedea with contrasting levels of sexual dimorphism.

The evolution of sexual dimorphism depends in part on the additive genetic variance-covariance matrices within females, within males, and across the sexes. We investigated quantitative genetics of floral biomass allocation in females and hermaphrodites of gynodioecious Schiedea adamantis (Caryophyllaceae). The G-matrices within females (G(f)), within hermaphrodites (G(m)), and between sexes (B) were compared to those for the closely related S. salicaria, which exhibits a lower frequency of females and less-pronounced sexual dimorphism. Additive genetic variation was detected in all measured traits in S. adamantis, with narrow-sense heritability from 0.34-1.0. Female allocation and floral size traits covaried more tightly than did those traits with allocation to stamens. Between-sex genetic correlations were all <1, indicating sex-specific expression of genes. Common principal-components analysis detected differences between G(f) and G(m) , suggesting potential for further independent evolution of the sexes. The two species of Schiedea differed in G(m) and especially so in G(f) , with S. adamantis showing greater genetic variation in capsule mass and tighter genetic covariation between female allocation traits and flower size in females. Despite greater sexual dimorphism in S. adamantis, genetic correlations between the two sexes (standardized elements of B) were similar to correlations between sexes in S. salicaria.

Sexually dimorphic inflorescence traits in a wind-pollinated species: heritabilities and genetic correlations in Schiedea adamantis (Caryophyllaceae).

Sexual dimorphism may be especially pronounced in wind-pollinated species because they lack the constraints of biotically pollinated species that must present their pollen and stigmas in similar positions to ensure pollen transfer. Lacking these constraints, the sexes of wind-pollinated species may diverge in response to the different demands of pollen dispersal and receipt, depending on the magnitude of genetic correlations preventing divergence between sexes. Patterns of sexual dimorphism and genetic variation were investigated for inflorescence traits in Schiedea adamantis (Caryophyllaceae), a species well adapted to wind-pollination, and compared to S. salicaria, a species with fewer adaptations to wind pollination. For S. adamantis, dimorphism was pronounced for inflorescence condensation and its components, including lateral flower number and pedicel length. Within sexes, genetic correlations between traits may constrain the relative shape of the inflorescence. Correlations detected across sexes may retard the evolution of sexual dimorphism in inflorescence structure, including features favoring enhanced dispersal and receipt of pollen. Despite genetic correlations across sexes, common principal components analysis showed that genetic variance-covariance matrices (G matrices) differed significantly between the sexes, in part because of greater genetic variation for flower number in hermaphrodites than in females. G matrices also differed between closely related S. adamantis and S. salicaria, indicating the potential for divergent evolution of inflorescence structure despite general similarities in morphology and pollination biology.

Genetic variation of ecophysiological traits in two gynodioecious species of Schiedea (Caryophyllaceae).

Evolution of dimorphic breeding systems may involve changes in ecophysiological traits as well as floral morphology because of greater resource demands on females. Differences between related species suggest that ecophysiological traits should be heritable, and species with higher female frequencies should show greater sexual differentiation. We used modified partial diallel crossing designs to estimate narrow-sense heritabilities and genetic correlations of sex-specific ecophysiological and morphological traits in closely related gynodioecious Schiedea salicaria (13% females) and Schiedea adamantis (39% females). In S. salicaria, hermaphrodites and females differed in photosynthetic rate and specific leaf area (SLA). Narrow-sense heritabilities were significant for stomatal conductance, SLA and inflorescence number in hermaphrodites, and for SLA and inflorescence number in females. Schiedea adamantis had no sexual dimorphism in measured traits; stomatal conductance, stem number and inflorescence number were heritable in females, and stem number was heritable in hermaphrodites. In both species, significant genetic correlations of traits between sexes were rare, indicating that traits can evolve independently in response to sex-differential selection. Significant genetic correlations were detected between certain traits within sexes of both species. Low heritability of some ecophysiological traits may reflect low additive genetic variability or high phenotypic plasticity in these traits.