Repeated loss of the ability of a wild pepper disease resistance gene to function at high temperatures suggests that thermoresistance is a costly trait.

Specificity in plant-pathogen gene-for-gene (GFG) interactions is determined by the recognition of pathogen proteins by the products of plant resistance (R) genes. The evolutionary dynamics of R genes in plant-virus systems is poorly understood. We analyse the evolution of the L resistance locus to tobamoviruses in the wild pepper Capsicum annuum var. glabriusculum (chiltepin), a crop relative undergoing incipient domestication. The frequency, and the genetic and phenotypic diversity, of the L locus was analysed in 41 chiltepin populations under different levels of human management over its distribution range in Mexico. The frequency of resistance was lower in Cultivated than in Wild populations. L-locus genetic diversity showed a strong spatial structure with no isolation-by-distance pattern, suggesting environment-specific selection, possibly associated with infection by the highly virulent tobamoviruses found in the surveyed regions. L alleles differed in recognition specificity and in the expression of resistance at different temperatures, broad-spectrum recognition of P0 + P1 pathotypes and expression above 32°C being ancestral traits that were repeatedly lost along L-locus evolution. Overall, loss of resistance co-occurs with incipient domestication and broad-spectrum resistance expressed at high temperatures has apparent fitness costs. These findings contribute to understand the role of fitness trade-offs in plant-virus coevolution.

Landscape genetics of the tropical willow Salix humboldtiana: influence of climate, salinity, and orography in an altitudinal gradient.

PREMISE: Gene flow in riparian ecosystems is influenced by landscape features such as orography, climate, and salinity. The downstream increase in genetic diversity (DIGD) hypothesis states that the unidirectionality of the watercourse causes an accumulation of genetic diversity toward downstream populations, while upstream populations are more structured and less diverse, especially in water-dispersed organisms. METHODS: We used chloroplast and nuclear microsatellites to characterize genetic diversity, structure, and gene flow patterns among populations of Salix humboldtiana across an elevation and salinity gradient on three rivers (Actopan, Antigua, and Blanco) in Mexico. We used optimization of resistance surface methods to determine whether genetic distances between populations are correlated with landscape features. RESULTS: Positive FIS values evidenced biparental inbreeding in some populations, particularly at higher elevations where lower niche availability constrains colonization and persistence. Four genetic groups were distinguished, corresponding to populations on the Actopan and Antigua rivers and upstream and downstream on the Blanco, but with high admixture between populations on the Actopan and Antigua rivers. Higher gene flow rates were found among proximate populations on the same river than among different rivers. Genetic diversity increased toward the river mouths, in support of the DIGD hypothesis, probably due to greater niche availability and larger population size. Differences among rivers in precipitation patterns and salinity, as well as geographic distance, were significant predictors of gene flow. CONCLUSIONS: Our results depict that the DIGD and gene flow patterns in S. humboldtiana result from the complex interaction among physiography, climate, river salinity, and life-history traits of the species.

Contemporary evolution of maize landraces and their wild relatives influenced by gene flow with modern maize varieties.

Mexico is recognized as the center of origin and domestication of maize. Introduction of modern maize varieties (MVs) into Mexico raised concerns regarding the possible effects of gene flow from MVs into maize landraces (LRs) and their wild relatives (WRs), teosintes. However, after more than 60 y from the release of the first MVs, the impact of the sympatry with LRs and their WRs has not been explored with genetic data. In this work, we assessed changes in the genomes of 7 maize LRs and 2 WR subspecies from collections spanning over 70 y. We compared the genotypes obtained by genotyping by sequencing (GBS) for LRs and WRs before and after the adoption of MVs, and observed introgression from sympatric MVs into LRs and into the WR Zea mays ssp. mexicana sampled after the year 2000. We also found a decrease in the paired divergence index (FST ) between MV-LR and MV-WR over the same time frame. Moreover, we determined that LR genetic diversity increased after 2000, probably as a result of gene flow from MVs introduced in the 1990s. Our findings allowed us to identify ongoing changes in the domesticated and wild maize genetic pools, and concur with previous works that have evaluated short-term gene flow from MVs into LRs in other crops. Our approach represents a useful tool for tracking evolutionary change in wild and domesticated genetic resources, as well as for developing strategies for their conservation.

Dispersal limitations and long-term persistence drive differentiation from haplotypes to communities within a tropical sky-island: Evidence from community metabarcoding.

Neutral theory proposes that dispersal stochasticity is one of the main drivers of local diversity. Haplotypes-level genetic variation can now be efficiently sampled from across whole communities, thus making it possible to test neutral predictions from the genetic to species-level diversity, and higher. However, empirical data is still limited, with the few studies to date coming from temperate latitudes. Here, we focus on a tropical mountain within the Transmexican Volcanic Belt to evaluate spatially fine-scale patterns of arthropod community assembly to understand the role of dispersal limitation and landscape features as drivers of diversity. We sampled whole-communities of arthropods for eight orders at a spatial scale ranging from 50 m to 19 km, using whole community metabarcoding. We explored multiple hierarchical levels, from individual haplotypes to lineages at 0.5, 1.5, 3, 5, and 7.5% similarity thresholds, to evaluate patterns of richness, turnover, and distance decay of similarity with isolation-by-distance and isolation-by-resistance (costs to dispersal given by landscape features) approaches. Our results showed that distance and altitude influence distance decay of similarity at all hierarchical levels. This holds for arthropod groups of contrasting dispersal abilities, but with different strength depending on the spatial scale. Our results support a model where local-scale differentiation mediated by dispersal constraints, combined with long-term persistence of lineages, is an important driver of diversity within tropical sky islands.

Phylogenomics and molecular species delimitation reveals great cryptic diversity of leaf-toed geckos (Phyllodactylidae: Phyllodactylus), ancient origins, and diversification in Mexico.

We utilize the efficient GBS technique to obtain thousands of nuclear loci and SNPs to reconstruct the evolutionary history of Mexican leaf-toed geckos (Phyllodactylus). Through the incorporation of unprecedented sampling for this group of geckos, in combination with genomic data analysis, we generate mostly consistent phylogenetic hypotheses using two approaches: supermatrix and coalescent-based inference. All topologies depict three, mutually exclusive major clades. Clade I comprises P. bordai and all species closer to P. bordai than to any other Phyllodactylus. Clade II comprises P. nocticolus and all species closer to P. nocticolus than to any other Phyllodactylus. Clade III comprises P. tuberculosus and all species closer to P. tuberculosus than to any other Phyllodactylus. Analyses estimate the age for the most recent common ancestor of Phyllodactylus in the Eocene (~43 mya), and the ancestors of each major clade date to the Eocene-Oligocene transition (32-36 mya). This group includes one late-Eocene lineage (P. bordai), Oligocene lineages (P. paucituberculatus, P. delcampi), but also topological patterns that indicate a recent radiation occurred during the Pleistocene on islands in the Gulf of California. The wide spatial and temporal scale indicates a complex and unique biogeographic history for each major clade. The 33 species delimited by BPP and stepping-stone BFD*coalescent based genomic approaches reflect this history. This diversity delimited for Mexican leaf-toed geckos demonstrates a vast underestimation in the number of species based on morphological data alone.

Anthropogenic disturbances jeopardize biodiversity conservation within tropical rainforest reserves.

Anthropogenic disturbances affecting tropical forest reserves have been documented, but their ecological long-term cumulative effects are poorly understood. Habitat fragmentation and defaunation are two major anthropogenic threats to the integrity of tropical reserves. Based on a long-term (four decades) study, we document how these disturbances synergistically disrupt ecological processes and imperil biodiversity conservation and ecosystem functioning at Los Tuxtlas, the northernmost tropical rainforest reserve in the Americas. Deforestation around this reserve has reduced the reserve to a medium-sized fragment (640 ha), leading to an increased frequency of canopy-gap formation. In addition, hunting and habitat loss have caused the decline or local extinction of medium and large herbivores. Combining empirical, experimental, and modeling approaches, we support the hypothesis that such disturbances produced a demographic explosion of the long-lived (≈120 y old, maximum height of 7 m) understory palm Astrocaryum mexicanum, whose population has increased from 1,243-4,058 adult individuals per hectare in only 39 y (annual growth rate of ca 3%). Faster gap formation increased understory light availability, enhancing seed production and the growth of immature palms, whereas release from mammalian herbivory and trampling increased survival of seedlings and juveniles. In turn, the palm's demographic explosion was followed by a reduction of tree species diversity, changing forest composition, altering the relative contribution of trees to forest biomass, and disrupting litterfall dynamics. We highlight how indirect anthropogenic disturbances (e.g., palm proliferation) on otherwise protected areas threaten tropical conservation, a phenomenon that is currently eroding the planet's richest repositories of biodiversity.

Human Management of a Wild Plant Modulates the Evolutionary Dynamics of a Gene Determining Recessive Resistance to Virus Infection.

This work analyses the genetic variation and evolutionary patterns of recessive resistance loci involved in matching-allele (MA) host-pathogen interactions, focusing on the pvr2 resistance gene to potyviruses of the wild pepper Capsicum annuum glabriusculum (chiltepin). Chiltepin grows in a variety of wild habitats in Mexico, and its cultivation in home gardens started about 25 years ago. Potyvirus infection of Capsicum plants requires the physical interaction of the viral VPg with the pvr2 product, the translation initiation factor eIF4E1. Mutations impairing this interaction result in resistance, according to the MA model. The diversity of pvr2/eIF4E1 in wild and cultivated chiltepin populations from six biogeographical provinces in Mexico was analysed in 109 full-length coding sequences from 97 plants. Eleven alleles were found, and their interaction with potyvirus VPg in yeast-two-hybrid assays, plus infection assays of plants, identified six resistance alleles. Mapping resistance mutations on a pvr2/eIF4E1 model structure showed that most were around the cap-binding pocket and strongly altered its surface electrostatic potential, suggesting resistance-associated costs due to functional constraints. The pvr2/eIF4E1 phylogeny established that susceptibility was ancestral and resistance was derived. The spatial structure of pvr2/eIF4E1 diversity differed from that of neutral markers, but no evidence of selection for resistance was found in wild populations. In contrast, the resistance alleles were much more frequent, and positive selection stronger, in cultivated chiltepin populations, where diversification of pvr2/eIF4E1 was higher. This analysis of the genetic variation of a recessive resistance gene involved in MA host-pathogen interactions in populations of a wild plant show that evolutionary patterns differ according to the plant habitat, wild or cultivated. It also demonstrates that human management of the plant population has profound effects on the diversity and the evolution of the resistance gene, resulting in the selection of resistance alleles.

Long-term in situ persistence of biodiversity in tropical sky islands revealed by landscape genomics.

Tropical mountains are areas of high species richness and endemism. Two historical phenomena may have contributed to this: (i) fragmentation and isolation of habitats may have promoted the genetic differentiation of populations and increased the possibility of allopatric divergence and speciation and (ii) the mountain areas may have allowed long-term population persistence during global climate fluctuations. These two phenomena have been studied using either species occurrence data or estimating species divergence times. However, only few studies have used intraspecific genetic data to analyse the mechanisms by which endemism may emerge at the microevolutionary scale. Here, we use landscape analysis of genomic SNP data sampled from two high-elevation plant species from an archipelago of tropical sky islands (the Trans-Mexican Volcanic Belt) to test for population genetic differentiation, synchronous demographic changes and habitat persistence. We show that genetic differentiation can be explained by the degree of glacial habitat connectivity among mountains and that mountains have facilitated the persistence of populations throughout glacial/interglacial cycles. Our results support the ongoing role of tropical mountains as cradles for biodiversity by uncovering cryptic differentiation and limits to gene flow.

Evolution of Trichobaris (Curculionidae) in relation to host plants: Geometric morphometrics, phylogeny and phylogeography.

The family Curculionidae (Coleoptera), the "true" weevils, have diversified tightly linked to the evolution of flowering plants. Here, we aim to assess diversification at a lower taxonomic level. We analyze the evolution of the genus Trichobaris in association with their host plants. Trichobaris comprises eight to thirteen species; their larvae feed inside the fruits of Datura spp. or inside the stem of wild and cultivated species of Solanaceae, such as potato, tobacco and tomato. We ask the following questions: (1) does the rostrum of Trichobaris species evolve according to the plant tissue used to oviposit, i.e., shorter rostrum to dig in stems and longer to dig in fruits? and (2) does Trichobaris diversify mainly in relation to the use of Datura species? For the first question, we estimated the phylogeny of Trichobaris based on four gene sequences (nuclear 18S and 28S rRNA genes and mitochondrial 16S rRNA and COI genes). Then, we carried out morphogeometric analyses of the Trichobaris species using 75 landmarks. For the second question, we calibrated a COI haplotype phylogeny using a constant rate of divergence to infer the diversification time of Trichobaris species, and we traced the host plant species on the haplotype network. We performed an ancestral state reconstruction analysis to infer recent colonization events and conserved associations with host plant species. We found that ancestral species in the Trichobaris phylogeny use the stem of Solanum plants for oviposition and display weak sexual dimorphism of rostrum size, whereas other, more recent species of Trichobaris display sexual dimorphism in rostrum size and use the fruits of Datura species, and a possible reversion to use the stem of Solanaceae was detected in one Trichobaris species. The use of Datura species by Trichobaris species is widely distributed on haplotype networks and restricted to Trichobaris species that originated ca. 5 ±â€¯1.5 Ma. Given that the origin of Trichobaris is estimated to be ca. 6 ±â€¯1.5 Ma, it is likely that Datura has played a role in its diversification.

Multi-locus phylogenetics, lineage sorting, and reticulation in Pinus subsection Australes.

PREMISE OF THE STUDY: Both incomplete lineage sorting and reticulation have been proposed as causes of phylogenetic incongruence. Disentangling these factors may be most difficult in long-lived, wind-pollinated plants with large population sizes and weak reproductive barriers. METHODS: We used solution hybridization for targeted enrichment and massive parallel sequencing to characterize low-copy-number nuclear genes and high-copy-number plastomes (Hyb-Seq) in 74 individuals of Pinus subsection Australes, a group of ~30 New World pine species of exceptional ecological and economic importance. We inferred relationships using methods that account for both incomplete lineage sorting and reticulation. KEY RESULTS: Concatenation- and coalescent-based trees inferred from nuclear genes mainly agreed with one another, but they contradicted the plastid DNA tree in recovering the Attenuatae (the California closed-cone pines) and Oocarpae (the egg-cone pines of Mexico and Central America) as monophyletic and the Australes sensu stricto (the southern yellow pines) as paraphyletic to the Oocarpae. The plastid tree featured some relationships that were discordant with morphological and geographic evidence and species limits. Incorporating gene flow into the coalescent analyses better fit the data, but evidence supporting the hypothesis that hybridization explains the non-monophyly of the Attenuatae in the plastid tree was equivocal. CONCLUSIONS: Our analyses document cytonuclear discordance in Pinus subsection Australes. We attribute this discordance to ancient and recent introgression and present a phylogenetic hypothesis in which mostly hierarchical relationships are overlain by gene flow.

Appropriate homoplasy metrics in linked SSRs to predict an underestimation of demographic expansion times.

BACKGROUND: Homoplasy affects demographic inference estimates. This effect has been recognized and corrective methods have been developed. However, no studies so far have defined what homoplasy metrics best describe the effects on demographic inference, or have attempted to estimate such metrics in real data. Here we study how homoplasy in chloroplast microsatellites (cpSSR) affects inference of population expansion time. cpSSRs are popular markers for inferring historical demography in plants due to their high mutation rate and limited recombination. RESULTS: In cpSSRs, homoplasy is usually quantified as the probability that two markers or haplotypes that are identical by state are not identical by descent (Homoplasy index, P). Here we propose a new measure of multi-locus homoplasy in linked SSR called Distance Homoplasy (DH), which measures the proportion of pairwise differences not observed due to homoplasy, and we compare it to P and its per cpSSR locus average, which we call Mean Size Homoplasy (MSH). We use simulations and analytical derivations to show that, out of the three homoplasy metrics analyzed, MSH and DH are more correlated to changes in the population expansion time and to the underestimation of that demographic parameter using cpSSR. We perform simulations to show that Approximate Bayesian Computation (ABC) can be used to obtain reasonable estimates of MSH and DH. Finally, we use ABC to estimate the expansion time, MSH and DH from a chloroplast SSR dataset in Pinus caribaea. To our knowledge, this is the first time that homoplasy has been estimated in population genetic data. CONCLUSIONS: We show that MSH and DH should be used to quantify how homoplasy affects estimates of population expansion time. We also demonstrate how ABC provides a methodology to estimate homoplasy in population genetic data.

Molecular systematics, species delimitation and diversification patterns of the Phyllodactylus lanei complex (Gekkota: Phyllodactylidae) in Mexico.

The description of cryptic gecko species worldwide has revealed both that many putative species are, in fact, conformed by a complex of morphologically conserved species that are genetically distinct and highly divergent, and that gecko species diversity could be underestimated. The taxonomy and species delimitation of geckos belonging to the genus Phyllodactylus is still controversial, 16 of which are distributed in Mexico and 13 are endemic. Although the large morphological variation shown by the Phyllodactylus species from Mexico has been amply documented, little is known about their genetic diversity and evolutionary relationships, and much less regarding cryptic speciation. Here, we included the most comprehensive sampling of populations and species of the Phyllodactylus lanei complex distributed in Mexico, and applied an analytical approach that included probabilistic phylogenetic analyses, jointly with species delimitation methods and Bayesian putative species validation analysis. Our results suggest the existence of 10 lineages within the complex, supporting the existence of cryptic species, and in great contrast with the current taxonomic proposal that includes only four subspecies. The most recent common ancestor (MRCA) for the P. lanei clade originated on the Early Eocene (∼54Mya), along the southern coasts of Mexico, followed by the highest diversification of the complex MRCA during the Eocene (34-56Mya). Lineages subsequently dispersed and diversified towards the northwest, and the diversification process ended with the most recent lineages inhabiting two islands on the coasts of Nayarit (Miocene; 5.5-23Mya). Our results highlight three vicariant events associated with the evolution of the lineages, two of them intimately related to the formation of the Sierra Madre del Sur and the Transmexican Volcanic Belt mountain ranges, main geographic barriers that isolated and facilitated the divergence and speciation in this group of geckos. Finally, we propose that there are 10 species in the P. lanei complex, from which four represent taxonomic changes and six are new species and require a formal description. We acknowledge that more analyses, including a detailed evaluation of morphological characters and use of more unlinked nuclear loci with enough variability, are needed to further support their taxonomic description.

Phylogeography of specialist weevil Trichobaris soror: a seed predator of Datura stramonium.

Can the genetic structure of a specialist weevil be explained by the geological history of their distribution zone? We analyze the genetic variation of the weevil Trichobaris soror, a specialist seed predator of Datura stramonium, in order to address this question. For the phylogeographic analysis we used the COI gene, and assessed species identity in weevil populations through geometric morphometric approach. In total, we found 53 haplotypes in 413 samples, whose genetic variation supports the formation of three groups: (1) the Transmexican Volcanic Belt (TVB group), (2) the Sierra Madre Sur (SMS group) and (3) the Balsas Basin (BB group). The morphometric analysis suggests that BB group is probably not T. soror. Our results have two implications: first, the phylogeographic pattern of T. soror is explained by both the formation of the geological provinces where it is currently distributed and the coevolution with its host plant, because the TVB and SMS groups could be separated due to the discontinuity of altitude between the geological provinces, but the recent population expansion of TVB group and the high frequency of only one haplotype can be due to specialization to the host plant. Second, we report a new record of a different species of weevil in BB group parasitizing D. stramonium fruits.

Effect of biodiversity changes in disease risk: exploring disease emergence in a plant-virus system.

The effect of biodiversity on the ability of parasites to infect their host and cause disease (i.e. disease risk) is a major question in pathology, which is central to understand the emergence of infectious diseases, and to develop strategies for their management. Two hypotheses, which can be considered as extremes of a continuum, relate biodiversity to disease risk: One states that biodiversity is positively correlated with disease risk (Amplification Effect), and the second predicts a negative correlation between biodiversity and disease risk (Dilution Effect). Which of them applies better to different host-parasite systems is still a source of debate, due to limited experimental or empirical data. This is especially the case for viral diseases of plants. To address this subject, we have monitored for three years the prevalence of several viruses, and virus-associated symptoms, in populations of wild pepper (chiltepin) under different levels of human management. For each population, we also measured the habitat species diversity, host plant genetic diversity and host plant density. Results indicate that disease and infection risk increased with the level of human management, which was associated with decreased species diversity and host genetic diversity, and with increased host plant density. Importantly, species diversity of the habitat was the primary predictor of disease risk for wild chiltepin populations. This changed in managed populations where host genetic diversity was the primary predictor. Host density was generally a poorer predictor of disease and infection risk. These results support the dilution effect hypothesis, and underline the relevance of different ecological factors in determining disease/infection risk in host plant populations under different levels of anthropic influence. These results are relevant for managing plant diseases and for establishing conservation policies for endangered plant species.

Histologic, metabolomic, and transcriptomic differences in fir trees from a peri-urban forest under chronic ozone exposure.

Urbanization modifies ecosystem conditions and evolutionary processes. This includes air pollution, mostly as tropospheric ozone (O3), which contributes to the decline of urban and peri-urban forests. A notable case are fir (Abies religiosa) forests in the peripheral mountains southwest of Mexico City, which have been severely affected by O3 pollution since the 1970s. Interestingly, some young individuals exhibiting minimal O3-related damage have been observed within a zone of significant O3 exposure. Using this setting as a natural experiment, we compared asymptomatic and symptomatic individuals of similar age (≤15 years old; n = 10) using histologic, metabolomic, and transcriptomic approaches. Plants were sampled during days of high (170 ppb) and moderate (87 ppb) O3 concentration. Given that there have been reforestation efforts in the region, with plants from different source populations, we first confirmed that all analyzed individuals clustered within the local genetic group when compared to a species-wide panel (Admixture analysis with ~1.5K SNPs). We observed thicker epidermis and more collapsed cells in the palisade parenchyma of needles from symptomatic individuals than from their asymptomatic counterparts, with differences increasing with needle age. Furthermore, symptomatic individuals exhibited lower concentrations of various terpenes (ß-pinene, ß-caryophylene oxide, α-caryophylene, and ß-α-cubebene) than asymptomatic trees, as evidenced through GC-MS. Finally, transcriptomic analyses revealed differential expression for 13 genes related to carbohydrate metabolism, plant defense, and gene regulation. Our results indicate a rapid and contrasting phenotypic response among trees, likely influenced by standing genetic variation and/or plastic mechanisms. They open the door to future evolutionary studies for understanding how O3 tolerance develops in urban environments, and how this knowledge could contribute to forest restoration.

La urbanización altera tanto las condiciones del ecosistema como los procesos evolutivos, siendo la contaminación del aire, principalmente el ozono troposférico (O3), un factor que contribuye al declive de los bosques urbanos y periurbanos. Un ejemplo destacado son los bosques de oyamel (Abies religiosa) en las montañas periféricas al suroeste de la Ciudad de México, que han sufrido graves afectaciones por la contaminación de O3 desde la década de 1970. Resulta curioso observar que algunos individuos jóvenes presentan un daño mínimo relacionado con el O3 dentro de zonas con una exposición significativa a este contaminante. Aprovechando este entorno como un experimento natural, hemos comparado individuos asintomáticos y sintomáticos de edad similar (≤15 años; n = 10) mediante enfoques histológicos, metabolómicos y transcriptómicos. Las muestras de plantas se recolectaron durante días con concentraciones altas (170 ppb) y moderadas (87 ppb) de O3. Dado que se han llevado a cabo esfuerzos de reforestación en la región con plantas de diferentes poblaciones, primero confirmamos que todos los individuos analizados se organizaron dentro del grupo genético local en comparación con un amplio panel poblacional de esta misma especie (Análisis de Admixture con ~1.5 K SNPs). Observamos una epidermis más gruesa y más células colapsadas en el parénquima en empalizada de las agujas de los individuos sintomáticos que de sus contrapartes asintomáticas, y estas diferencias aumentaban con la edad de la aguja. Además, los individuos sintomáticos exhibieron concentraciones más bajas de varios terpenos (ß­pineno, óxido de ß­cariofileno, α­cariofileno y ß­α­cubebeno) que los árboles asintomáticos, según se evidenció mediante GC­MS. Por último, los análisis transcriptómicos revelaron una expresión diferencial para trece genes relacionados con el metabolismo de carbohidratos, la defensa de plantas y la regulación génica. Nuestros resultados indican una respuesta fenotípica rápida y contrastante entre los árboles, probablemente influenciada por la variación genética presente y/o mecanismos plásticos. Estos hallazgos abren la puerta a futuros estudios evolutivos para comprender cómo se desarrolla la tolerancia al O3 en entornos urbanos y cómo este conocimiento podría contribuir a la restauración forestal.

Decentralization and Integration of Advanced Cardiac Care for the World's Poorest Billion Through the PEN-Plus Strategy for Severe Chronic Non-Communicable Disease.

Rheumatic and congenital heart disease, cardiomyopathies, and hypertensive heart disease are major causes of suffering and death in low- and lower middle-income countries (LLMICs), where the world's poorest billion people reside. Advanced cardiac care in these counties is still predominantly provided by specialists at urban tertiary centers, and is largely inaccessible to the rural poor. This situation is due to critical shortages in diagnostics, medications, and trained healthcare workers. The Package of Essential NCD Interventions - Plus (PEN-Plus) is an integrated care model for severe chronic noncommunicable diseases (NCDs) that aims to decentralize services and increase access. PEN-Plus strategies are being initiated by a growing number of LLMICs. We describe how PEN-Plus addresses the need for advanced cardiac care and discuss how a global group of cardiac organizations are working through the PEN-Plus Cardiac expert group to promote a shared operational strategy for management of severe cardiac disease in high-poverty settings.

Correction: Decentralization and Integration of Advanced Cardiac Care for the World's Poorest Billion Through the PEN-Plus Strategy for Severe Chronic Non-Communicable Disease.

[This corrects the article DOI: 10.5334/gh.1313.].

Genetic, morphological, geographical and ecological approaches reveal phylogenetic relationships in complex groups, an example of recently diverged pinyon pine species (Subsection Cembroides).

Elucidating phylogenetic relationships and species boundaries within complex taxonomic groups is challenging for intrinsic and extrinsic (i.e., technical) reasons. Mexican pinyon pines are a complex group whose phylogenetic relationships and species boundaries have been widely studied but poorly resolved, partly due to intrinsic ecological and evolutionary features such as low morphological and genetic differentiation caused by recent divergence, hybridization and introgression. Extrinsic factors such as limited sampling and difficulty in selecting informative molecular markers have also impeded progress. Some of the Mexican pinyon pines are of conservation concern but others may remain unprotected because the species boundaries have not been established. In this study we combined approaches to resolve the phylogenetic relationships in this complex group and to establish species boundaries in four recently diverged taxa: P. discolor, P. johannis, P. culminicola and P. cembroides. We performed phylogenetic analyses using the chloroplast markers matK and psbA-trnH as well as complete and partial chloroplast genomes of species of Subsection Cembroides. Additionally, we performed a phylogeographic analysis combining genetic data (18 chloroplast markers), morphological data and geographical data to define species boundaries in four recently diverged taxa. Ecological divergence was supported by differences in climate among localities for distinct genetic lineages. Whereas the phylogenetic analysis inferred with matK and psbA-trnH was unable to resolve the relationships in this complex group, we obtained a resolved phylogeny with the use of the chloroplast genomes. The resolved phylogeny was concordant with a haplotype network obtained using chloroplast markers. In species with potential for recent divergence, hybridization or introgression, nonhierarchical network-based approaches are probably more appropriate to protect against misclassification due to incomplete lineage sorting. The boundaries among genetic lineages were delimited by the inclusion of morphological, geographical and ecological data in the haplotype network. These multiple lines of evidence help to assign species boundaries in this complex group. P. johannis, P. discolor, P. culminicola and P. cembroides are different species based on their genetic, morphological and ecological niche differences. We suggest a reevaluation of the conservation status of these species considering the information generated in this study.

Genetic variation in the Cytb gene of human cerebral Taenia solium cysticerci recovered from clinically and radiologically heterogeneous patients with neurocysticercosis.

Neurocysticercosis (NC) is a clinically and radiologically heterogeneous parasitic disease caused by the establishment of larval Taenia solium in the human central nervous system. Host and/or parasite variations may be related to this observed heterogeneity. Genetic differences between pig and human-derived T. solium cysticerci have been reported previously. In this study, 28 cysticerci were surgically removed from 12 human NC patients, the mitochondrial gene that encodes cytochrome b was amplified from the cysticerci and genetic variations that may be related to NC heterogeneity were characterised. Nine different haplotypes (Ht), which were clustered in four haplogroups (Hg), were identified. Hg 3 and 4 exhibited a tendency to associate with age and gender, respectively. However, no significant associations were found between NC heterogeneity and the different T. solium cysticerci Ht or Hg. Parasite variants obtained from patients with similar NC clinical or radiological features were genetically closer than those found in groups of patients with a different NC profile when using the Mantel test. Overall, this study establishes the presence of genetic differences in the Cytb gene of T. solium isolated from human cysticerci and suggests that parasite variation could contribute to NC heterogeneity.

Helmet Shape and Phylogeography of the Treehopper Membracis mexicana.

Membracis mexicana (Hemiptera: Membracidae) is distributed in four biogeographic provinces of Mexico. Field observations indicate that there are different forms of this species, but the distribution of the phenotype and the genetic variation of this species have not been clarified. The aim of this study was to quantify the phenotypic and genetic variation of M. mexicana and determine whether the configuration of biogeographic provinces impacts the distribution of this variation. To achieve this, we analyzed 307 photographs using 19 landmarks and geometric morphometrics to quantify the phenotypic variation in helmets. We sequenced five molecular markers for 205 individuals to describe the phylogeographic pattern. As a result, we identified three morphological configurations of the helmet of M. mexicana and two genetic lineages. The morphotypes are (1) a large and wide helmet with small dorsal spots, (2) a small and narrow helmet with large dorsal spots, and (3) a small and narrow helmet with small spots. Genetic lineages are distributed in southeast and western Mexico. The western lineage corresponds to two helmet morphotypes (1 and 2) and the southeast lineage to morphotype 3. We found that the larger helmets correspond to the western lineage and are distributed in Trans-Mexican Volcanic Belt and Pacific lowlands provinces, whereas the smallest helmets correspond to the southeast lineage and are present in the Veracruzan and Yucatan Peninsula provinces.