RESUMO
Sex chromosomes are evolutionarily labile in many animals and sometimes fuse with autosomes, creating so-called neo-sex chromosomes. Fusions between sex chromosomes and autosomes have been proposed to reduce sexual conflict and to promote adaptation and reproductive isolation among species. Recently, advances in genomics have fuelled the discovery of such fusions across the tree of life. Here, we discovered multiple fusions leading to neo-sex chromosomes in the sapho subclade of the classical adaptive radiation of Heliconius butterflies. Heliconius butterflies generally have 21 chromosomes with very high synteny. However, the five Heliconius species in the sapho subclade show large variation in chromosome number ranging from 21 to 60. We find that the W chromosome is fused with chromosome 4 in all of them. Two sister species pairs show subsequent fusions between the W and chromosomes 9 or 14, respectively. These fusions between autosomes and sex chromosomes make Heliconius butterflies an ideal system for studying the role of neo-sex chromosomes in adaptive radiations and the degeneration of sex chromosomes over time. Our findings emphasize the capability of short-read resequencing to detect genomic signatures of fusion events between sex chromosomes and autosomes even when sex chromosomes are not explicitly assembled.
Assuntos
Borboletas , Evolução Molecular , Cromossomos Sexuais , Animais , Borboletas/genética , Cromossomos Sexuais/genética , Feminino , Masculino , Filogenia , Genômica/métodos , Sintenia , Cromossomos de Insetos/genética , Genoma de InsetoRESUMO
Geographical barriers like mountain ranges impede genetic exchange among populations, promoting diversification. The effectiveness of these barriers in limiting gene flow varies between lineages due to each species' dispersal modes and capacities. Our understanding of how the Andes orogeny contributes to species diversification comes from well-studied vertebrates and a few arthropods and plants, neglecting organisms unable to fly or walk long distances. Some arachnids, such as Gasteracantha cancriformis, have been hypothesized to disperse long distances via ballooning (i.e. using their silk to interact with the wind). Yet, we do not know how the environment and geography shape its genetic diversity. Therefore, we tested whether the Andes contributed to the diversification of G. cancriformis acting as an absolute or semi-permeable barrier to genetic connectivity between populations of this spider at opposite sides of the mountain range. We sampled thousands of loci across the distribution of the species and implemented population genetics, phylogenetic, and landscape genetic analyses. We identified two genetically distinct groups structured by the Central Andes, and a third less structured group in the Northern Andes that shares ancestry with the previous two. This structure is largely explained by the altitude along the Andes, which decreases in some regions, possibly facilitating cross-Andean dispersal and gene flow. Our findings support that altitude in the Andes plays a major role in structuring populations in South America, but the strength of this barrier can be overcome by organisms with long-distance dispersal modes together with altitudinal depressions.
Las barreras geográficas como las cordilleras montañosas impiden el intercambio genético entre poblaciones, promoviendo la diversificación. La efectividad de estas barreras para limitar el flujo genético varía entre linajes debido a los modos y capacidades de dispersión de cada especie. Nuestra comprensión de cómo la orogenia de los Andes contribuye a la diversificación de especies proviene de vertebrados y algunos artrópodos y plantas bien estudiados, descuidando a los organismos incapaces de volar o caminar grandes distancias. Se ha hipotetizado que algunas arañas, como Gasteracantha cancriformis, se dispersan a grandes distancias mediante la técnica de "ballooning" (es decir, utilizando su seda para interactuar con el viento). Sin embargo, no sabemos cómo el entorno y la geografía han dado forma a su diversidad genética. Por lo tanto, probamos si los Andes contribuyeron a la diversificación de G. cancriformis actuando como una barrera absoluta o permeable para la conectividad genética entre poblaciones de esta araña en lados opuestos de la cordillera. Muestreamos miles de loci a través de la distribución de la especie e implementamos análisis de genética de poblaciones, filogenéticos y de genética del paisaje. Identificamos dos grupos genéticamente distintos estructurados por los Andes Centrales, y un tercer grupo menos estructurado en los Andes del Norte que comparte ascendencia con los dos anteriores. Esta estructura se explica en gran medida por la altitud a lo largo de los Andes, que disminuye en algunas regiones, posiblemente facilitando la dispersión y el flujo genético a través de los Andes. Nuestros hallazgos apoyan que la altitud en los Andes juega un papel importante en la estructuración de las poblaciones en América del Sur, pero la fuerza de esta barrera puede ser superada por organismos con modos de dispersión a larga distancia junto con depresiones altitudinales.
Assuntos
Fluxo Gênico , Genética Populacional , Filogenia , Aranhas , Animais , Aranhas/genética , Variação Genética , Geografia , Altitude , América do SulRESUMO
Hybridization allows adaptations to be shared among lineages and may trigger the evolution of new species1,2. However, convincing examples of homoploid hybrid speciation remain rare because it is challenging to demonstrate that hybridization was crucial in generating reproductive isolation3. Here we combine population genomic analysis with quantitative trait locus mapping of species-specific traits to examine a case of hybrid speciation in Heliconius butterflies. We show that Heliconius elevatus is a hybrid species that is sympatric with both parents and has persisted as an independently evolving lineage for at least 180,000 years. This is despite pervasive and ongoing gene flow with one parent, Heliconius pardalinus, which homogenizes 99% of their genomes. The remaining 1% introgressed from the other parent, Heliconius melpomene, and is scattered widely across the H. elevatus genome in islands of divergence from H. pardalinus. These islands contain multiple traits that are under disruptive selection, including colour pattern, wing shape, host plant preference, sex pheromones and mate choice. Collectively, these traits place H. elevatus on its own adaptive peak and permit coexistence with both parents. Our results show that speciation was driven by introgression of ecological traits, and that speciation with gene flow is possible with a multilocus genetic architecture.
Assuntos
Borboletas , Introgressão Genética , Especiação Genética , Hibridização Genética , Locos de Características Quantitativas , Animais , Feminino , Masculino , Borboletas/anatomia & histologia , Borboletas/classificação , Borboletas/genética , Fluxo Gênico , Introgressão Genética/genética , Genoma de Inseto/genética , Preferência de Acasalamento Animal , Fenótipo , Pigmentação/genética , Locos de Características Quantitativas/genética , Isolamento Reprodutivo , Seleção Genética/genética , Especificidade da Espécie , Simpatria/genética , Asas de Animais/anatomia & histologia , Asas de Animais/metabolismoRESUMO
Introducción. Las duplicaciones gástricas son entidades congénitas poco frecuentes que se diagnostican principalmente en las etapas tempranas de la vida, y rara vez en pacientes adultos. El objetivo de este artículo fue presentar el caso de un adulto con esta patología, tratado exitosamente mediante cirugía. Caso clínico. Mujer de 26 años de edad con epigastralgia crónica refractaria a manejo médico, a quien durante endoscopia digestiva superior se le identificó una lesión quística sugestiva de tumor estromal gastrointestinal, confirmada por ultrasonido endoscópico. Resultados. Se realizó una resección quirúrgica laparoscópica asistida por endoscopia, con buena evolución postoperatoria. El estudio anatomo-patológico informó la presencia de un quiste de duplicación gástrica. Conclusiones. A pesar de las ayudas diagnósticas disponibles en la actualidad, esta patología representa un reto diagnóstico importante que, en muchas ocasiones solo puede ser confirmado mediante el estudio anatomo-patológico. En paciente asintomático, continúa la controversia entre observarlo o llevarlo a cirugía, por el riesgo de malignidad. Actualmente, el manejo de las duplicaciones gástricas en adultos se considera eminentemente quirúrgico. Las resecciones laparoscópicas y el uso de endoscopia intraoperatoria permiten garantizar la resección completa de la lesión, preservando la mayor cantidad de tejido sano adyacente y previniendo estenosis o deformidades gástricas que afecten su adecuado funcionamiento.
Introduction. Gastric duplications are rare congenital entities that are diagnosed primarily in early life, and rarely in adult patients. The objective of this article was to present the case of an adult with this pathology, successfully treated by surgery. Clinical case. A 26-year-old woman with chronic epigastralgia refractory to medical management, who during upper digestive endoscopy was identified with a cystic lesion suggestive of gastro-intestinal stromal tumor, confirmed by endoscopic ultrasound. Results. A laparoscopic surgical resection assisted by endoscopy was performed, with good postoperative evolution. The anatomopathological study reported the presence of a gastric duplication cyst. Conclusions. Despite the diagnostic adjuncts currently available, this pathology represents an important diagnostic challenge that, in many cases, can only be confirmed through pathology. In asymptomatic patients, the controversy continues between observing them or taking them to surgery due to the risk of malignancy. Currently, the management of gastric duplications in adults is considered eminently surgical. Laparoscopic resections and the use of intraoperative endoscopy ensure complete resection of the lesion, preserving the greatest amount of adjacent healthy tissue and preventing gastric stenosis or deformities that affect its proper functioning.
Assuntos
Humanos , Procedimentos Cirúrgicos do Sistema Digestório , Endoscopia Gastrointestinal , Gastroenteropatias , Estômago , Laparoscopia , EndossonografiaRESUMO
Visual preferences are important drivers of mate choice and sexual selection, but little is known of how they evolve at the genetic level. In this study, we took advantage of the diversity of bright warning patterns displayed by Heliconius butterflies, which are also used during mate choice. Combining behavioral, population genomic, and expression analyses, we show that two Heliconius species have evolved the same preferences for red patterns by exchanging genetic material through hybridization. Neural expression of regucalcin1 correlates with visual preference across populations, and disruption of regucalcin1 with CRISPR-Cas9 impairs courtship toward conspecific females, providing a direct link between gene and behavior. Our results support a role for hybridization during behavioral evolution and show how visually guided behaviors contributing to adaptation and speciation are encoded within the genome.
Assuntos
Borboletas , Proteínas de Ligação ao Cálcio , Visão de Cores , Genes de Insetos , Introgressão Genética , Preferência de Acasalamento Animal , Seleção Sexual , Animais , Feminino , Borboletas/genética , Borboletas/fisiologia , Proteínas de Ligação ao Cálcio/genética , Visão de Cores/genética , Genoma , Hibridização Genética , Seleção Sexual/genéticaRESUMO
Trichoderma species are known for their mycoparasitic activity against phytopathogenic fungi that cause significant economic losses in agriculture. During mycoparasitism, Trichoderma spp. recognize molecules produced by the host fungus and release secondary metabolites and hydrolytic enzymes to kill and degrade the host's cell wall. Here, we explored the participation of the Trichoderma atroviride RNAi machinery in the interaction with six phytopathogenic fungi of economic importance. We determined that both Argonaute-3 and Dicer-2 play an essential role during mycoparasitism. Using an RNA-Seq approach, we identified that perception, detox, and cell wall degradation depend on the T. atroviride-RNAi when interacting with Alternaria alternata, Rhizoctonia solani AG2, and R. solani AG5. Furthermore, we constructed a gene co-expression network that provides evidence of two gene modules regulated by RNAi, which play crucial roles in essential processes during mycoparasitism. In addition, based on small RNA-seq, we conclude that siRNAs regulate amino acid and carbon metabolism and communication during the Trichoderma-host interaction. Interestingly, our data suggest that siRNAs might regulate allorecognition (het) and transport genes in a cross-species manner. Thus, these results reveal a fine-tuned regulation in T. atroviride dependent on siRNAs that is essential during the biocontrol of phytopathogenic fungi, showing a greater complexity of this process than previously established.IMPORTANCEThere is an increasing need for plant disease control without chemical pesticides to avoid environmental pollution and resistance, and the health risks associated with the application of pesticides are increasing. Employing Trichoderma species in agriculture to control fungal diseases is an alternative plant protection strategy that overcomes these issues without utilizing chemical fungicides. Therefore, understanding the biocontrol mechanisms used by Trichoderma species to antagonize other fungi is critical. Although there has been extensive research about the mechanisms involved in the mycoparasitic capability of Trichoderma species, there are still unsolved questions related to how Trichoderma regulates recognition, attack, and defense mechanisms during interaction with a fungal host. In this work, we report that the Argonaute and Dicer components of the RNAi machinery and the small RNAs they process are essential for gene regulation during mycoparasitism by Trichoderma atroviride.
Assuntos
Hypocreales , Praguicidas , Plantas , Comunicação , Regulação Fúngica da Expressão GênicaRESUMO
Traits under divergent ecological selection that also function during mating can be important in maintaining species boundaries. Few studies have considered mutual mate choice, where both males and females base mating decisions on the same trait. Wing colouration in Heliconius butterflies evolved as a warning signal but also functions as a mating cue. We investigated the contribution of visual preference to assortative mating in an aposematic butterfly Heliconius cydno in the context of reproductive isolation with its sympatric, visually distinct relative Heliconius melpomene. Heliconius cydno have conspicuous white bands on their forewings, whereas those of H. melpomene are red in colour. We predicted that both sexes of H. cydno contributed to assortative mating by exhibiting visual preference towards conspecific wing colouration. We analysed published and new data from preference experiments, in which males were presented with conspecific and H. melpomene females. We also recorded female responses and mating outcomes in choice experiments, involving conspecific males with either the original white or artificially painted red forewing bands. Both sexes of H. cydno responded more positively towards the conspecific colouration, and males strongly preferred females of its own colours. In contrast, male colouration did not predict mating outcomes in female choice experiments. As courtships are initiated by males in butterflies, our findings suggest that female visual preference might be of secondary importance in H. cydno. Our data also suggest that the contribution of visual preference to reproductive isolation might be unequal between H. cydno and its sympatric relative H. melpomene.
Assuntos
Borboletas , Animais , Feminino , Masculino , Reprodução , Fenótipo , Isolamento Reprodutivo , SimpatriaRESUMO
Vertical gradients in microclimate, resource availability, and interspecific interactions are thought to underly stratification patterns in tropical insect communities. However, only a few studies have explored the adaptive significance of vertical space use during the early stages of reproductive isolation. We analysed flight-height variation across speciation events in Heliconius butterflies, representing parallel colonizations of high-altitude forest. We measured flight-height in wild H. erato venus and H. chestertonii, parapatric lowland and mountain specialists, respectively, and found that H. chestertonii consistently flies at a lower height. By comparing our data to previously published results for the ecologically equivalent H. e. cyrbia (lowland) and H. himera (high altitude), we found that the species flying closest to the ground are those that recently colonized high-altitude forests. We show that these repeated trends largely result from shared patterns of ecological selection producing parallel trait-shifts in H. himera and H. chestertonii. Although our results imply a signature of local adaptation, we did not find an association between resource distribution and flight-height in H. e. venus and H. chestertonii. We discuss how this pattern may be explained by variations in forest structure and microclimate. Overall, our findings underscore the importance of behavioural adjustments during early divergence mediated by altitude-shifts.
Assuntos
Borboletas , Animais , Altitude , FenótipoRESUMO
Introducción. El objetivo del estudio fue analizar el impacto del uso de la tomografía corporal total en la evaluación de los pacientes con trauma penetrante por proyectil de arma de fuego y hemodinámicamente inestables atendidos en un centro de referencia de trauma. Métodos. Se realizó un estudio analítico, retrospectivo, con base en un subanálisis del registro de la Sociedad Panamericana de Trauma Fundación Valle del Lili. Se incluyeron los pacientes con trauma penetrante por proyectil de arma de fuego atendidos entre 2018 y 2021. Se excluyeron los pacientes con trauma craneoencefálico severo, trauma leve y en condición in extremis. Resultados. Doscientos pacientes cumplieron los criterios de elegibilidad, 115 fueron estudiados con tomografía corporal total y se compararon con 85 controles. La mortalidad intrahospitalaria en el grupo de tomografía fue de 4/115 (3,5 %) vs 10/85 (12 %) en el grupo control. En el análisis multivariado se identificó que la tomografía no tenía asociación significativa con la mortalidad (aOR=0,46; IC95% 0,10-1,94). El grupo de tomografía tuvo una reducción relativa del 39 % en la frecuencia de cirugías mayores, con un efecto asociado en la disminución de la necesidad de cirugía (aOR=0,47; IC95% 0,22-0,98). Conclusiones. La tomografía corporal total fue empleada en el abordaje inicial de los pacientes con trauma penetrante por proyectil de arma de fuego y hemodinámicamente inestables. Su uso no se asoció con una mayor mortalidad, pero sí con una menor frecuencia de cirugías mayores.
Introduction. This study aims to assess the impact of whole-body computed tomography (WBCT) in the evaluation of patients with penetrating gunshot wounds (GSW) who are hemodynamically unstable and treated at a trauma referral center. Methods. An analytical, retrospective study was conducted based on a subanalysis of the Panamerican Trauma Society-FVL registry. Patients with GSW treated between 2018 and 2021 were included. Patients with severe cranioencephalic trauma, minor trauma, and those in extremis were excluded. Patients with and without WBCT were compared. The primary outcome was in-hospital mortality, and the secondary outcome was the frequency of major surgeries (thoracotomy, sternotomy, cervicotomy, and/or laparotomy) during initial care. Results. Two hundred eligible patients were included, with 115 undergoing WBCT and compared to 85 controls. In-hospital mortality in the WBCT group was 4/115 (3.5%) compared to 10/85 (12%) in the control group. Multivariate analysis showed that WBCT was not significantly associated to mortality (aOR: 0.46; 95% CI 0.10-1.94). The WBCT group had a relative reduction of 39% in the frequency of major surgeries, with an associated effect on reducing the need for surgery (aOR: 0.47; 95% CI 0.22-0.98). Conclusions. Whole-body computed tomography was employed in the initial management of patients with penetrating firearm projectile injuries and hemodynamic instability. The use of WBCT was not associated with mortality but rather with a reduction in the frequency of major surgery.
Assuntos
Humanos , Choque Hemorrágico , Ferimentos e Lesões , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único , Choque Traumático , Procedimentos Cirúrgicos Operatórios , Mortalidade HospitalarRESUMO
Introducción. La neoplasia colorrectal es una patología oncológica muy frecuente a nivel mundial y una de las causas más comunes de mortalidad por cáncer. La epidemiologia, diagnóstico y tratamiento han sido ampliamente estudiadas, mientras que los datos sobre la enfermedad metastásica siguen siendo escasos. El hígado es el órgano más comúnmente afectado y algunos estudios sugieren diferencias en sobrevida y resecabilidad según la localización del tumor primario. El objetivo de este estudio fue establecer el comportamiento y resecabilidad de neoplasias avanzadas colorrectales en dos hospitales de la ciudad de Medellín, Colombia. Métodos. Estudio analítico retrospectivo para identificar los patrones de las metástasis hepáticas y sus características en función de las diferencias clínicas, histológicas y endoscópicas del tumor colorrectal primario entre 2015 y 2020. Resultados. Se recolectaron 54 pacientes con neoplasia colorrectal y metástasis hepáticas, 21 (39 %) derechas y 33 (61 %) izquierdas. El número de metástasis promedio fue de 3,1 en tumores del lado derecho y de 2,4 del izquierdo y el tamaño promedio de cada lesión fue de 4,9 y 4,2 cm, respectivamente. La tasa de resecabilidad fue del 42 % en los tumores derechos y del 82 % en los izquierdos. Las lesiones metacrónicas presentaron una tasa de resecabilidad del 90 % y las sincrónicas del 61 %. Conclusión. En este estudio, las lesiones originadas en neoplasias primarias del colon izquierdo y las lesiones metacrónicas fueron factores pronósticos favorables para la resecabilidad, un factor que impacta en la sobrevida y el tiempo libre de enfermedad de estos pacientes.
Introduction. Colorectal tumor is the most frequent pathology worldwide and one of the most common causes of mortality attributed to cancer. Epidemiology, diagnosis and treatment have been extensively studied, while information on metastatic disease remains scarce, despite being the main cause of death. Some studies suggest differences in terms of survival and resectability according to the anatomical location of the primary tumor. The aim is to establish the behavior and resectability of advanced cancers in two high-complex hospitals in the city of Medellín, Colombia. Methods. Cross-sectional observational study from secondary sources of information based on a retrospective cohort, using available data from adult patients with colorectal cancer and liver metastases between 2015 and 2020. Results. Fifty-four patients with colorectal neoplasms and liver metastases were collected, of which 21 (39%) were on the right side. The average number of liver metastases was 3.1 on the right side and 2.4 on the left, and the average size of each metastatic lesion was 4.9 cm and 4.2 cm, respectively. The resectability rate was 42% in the right tumors and 82% in the left ones. Metachronous lesions had a resectability rate of 90% and synchronous ones 61%. Conclusion. The complete resectability of liver metastatic lesions is the only therapeutic alternative with impact, in terms of survival and disease-free time in these patients. The favorable prognostic factors for the resectability of these lesions in our study were those originating from left primary tumors and metachronous lesions, where less liver tumor involvement was evidenced
Assuntos
Humanos , Neoplasias Colorretais , Metástase Neoplásica , Metastasectomia , Hepatectomia , Neoplasias HepáticasRESUMO
Parallel evolution of morphological traits is widely reported, providing evidence for the role of local conditions in driving adaptive divergence. Comparatively, fewer studies have tested for parallelism in behavior, and it is less clear to what extent heritable behavioral shifts contribute to adaptive divergence. We exploit repeated incipient speciation across altitudinal gradients to explore behavior and physiology in Heliconius butterflies adapted to high-elevation. We performed common garden experiments with H. chestertonii, a high-altitude specialist from the Colombian Cordillera Occidental, and H. erato venus, a low-elevation proxy for the ancestral population, and compared our results to existing data for an equivalent Ecuadorian taxa-pair. Using broad-scale climatic data, we show that both pairs diverge across similar ecological gradients, confirmed using localized data loggers in the ranges of H. chestertonii and H. e. venus. We further show that H. chestertonii and H. e. venus have divergent activity patterns, attributable to different responses to microclimate, and life histories. Finally, we provide evidence for parallelism in these traits with H. himera and H. e. cyrbia. We propose that this is a result of selection associated with independent colonizations of high-altitude forests, emphasizing the importance of heritable behavioral and physiological adaptations during population divergence and speciation.
Assuntos
Borboletas , Animais , Borboletas/fisiologia , Especiação Genética , Fenótipo , FlorestasRESUMO
Heliconius butterflies are an ideal organism for studying ecology, behavior, adaptation, and speciation. These butterflies can be found in various locations and habitats in Central and South America, where they encounter and interact with different sources of pollen, nectar, and host plants. However, there is limited knowledge on how geographic and habitat variations affect the microbiota of these insects, and whether microbial associates play a role in their ability to exploit different habitats. To date, research on the microbial communities associated with Heliconius has mainly focused on host phylogenetic signal in microbiomes or microbiome characterization in specific communities of butterflies. In this study, we characterized the microbiomes of several species and populations of Heliconius from distant locations that represent contrasting environments. We found that the microbiota of different Heliconius species is taxonomically similar but vary in abundance. Notably, this variation is associated with a major geographic barrier-the Central Cordillera of Colombia. Additionally, we confirmed that this microbiota is not associated with pollen-feeding. Therefore, it seems likely that geography shapes the abundance of microbiota that the butterfly carries, but not the taxonomic diversity of the microbial community. Based on the current evidence, the bacterial microbiota associated with Heliconius does not appear to play a beneficial role for these butterflies.
Assuntos
Borboletas , Microbiota , Animais , Borboletas/microbiologia , Filogenia , Pólen , GeografiaRESUMO
Why warning patterns are so diverse is an enduring evolutionary puzzle. Because predators associate particular patterns with unpleasant experiences, an individual's predation risk should decrease as the local density of its warning pattern increases, promoting pattern monomorphism. Distasteful Heliconius butterflies are known for their diversity of warning patterns. Here, we explore whether interlocus sexual conflict can contribute to their diversification. Male Heliconius use warning patterns as mating cues, but mated females may suffer costs if this leads to disturbance, favouring novel patterns. Using simulations, we show that under our model conditions drift alone is unlikely to cause pattern diversification, but that sexual conflict can assist such a process. We also find that genetic architecture influences the evolution of male preferences, which track changes in warning pattern due to sexual selection. When male attraction imposes costs on females, this affects the speed at which novel pattern alleles increase. In two experiments, females laid fewer eggs with males present. However, although males in one experiment showed less interest in females with manipulated patterns, we found no evidence that female colouration mitigates sex-specific costs. Overall, male attraction to conspecific warning patterns may impose an unrecognized cost on Heliconius females, but further work is required to determine this experimentally.
Assuntos
Borboletas , Animais , Feminino , Masculino , Borboletas/genética , Comportamento Sexual Animal , Reprodução , Seleção Sexual , Evolução BiológicaRESUMO
Repeated evolution can provide insight into the mechanisms that facilitate adaptation to novel or changing environments. Here we study adaptation to altitude in two tropical butterflies, Heliconius erato and H. melpomene, which have repeatedly and independently adapted to montane habitats on either side of the Andes. We sequenced 518 whole genomes from altitudinal transects and found many regions differentiated between highland (~ 1200 m) and lowland (~ 200 m) populations. We show repeated genetic differentiation across replicate populations within species, including allopatric comparisons. In contrast, there is little molecular parallelism between the two species. By sampling five close relatives, we find that a large proportion of divergent regions identified within species have arisen from standing variation and putative adaptive introgression from high-altitude specialist species. Taken together our study supports a role for both standing genetic variation and gene flow from independently adapted species in promoting parallel local adaptation to the environment.
Assuntos
Borboletas , Adaptação Fisiológica/genética , Altitude , Animais , Borboletas/genética , Fenótipo , FilogeniaRESUMO
BACKGROUND: The evolutionary history of biodiversity in South America has been poorly studied in the seasonal dry tropical forest (SDTF). Species diversification in this ecosystem may have a twofold explanation. First, intermittent connections in the middle and late Pleistocene promoted species dispersal and/or genetic connectivity between lineages isolated in disjunct patches of forest. Second, allopatric speciation proceeded immediately after the formation and colonization of the SDTF in the Neogene. Here we studied the diversification of Psammolestes, a genus endemic of the SDTF and naturally infected with Trypanosoma cruzi (agent of Chagas disease), using a combination of phylogenetic, population genetics and niche model methods, and evaluated the reliability of the three morphospecies currently recognized. RESULTS: Our multilocus analyses recovered P. coreodes and P. tertius in a monophyletic clade sister to P. arthuri. Species delimitation tests recovered these lineages as different species despite the shared genetic variation observed between P. coreodes and P. tertius in five genes. Also, genetic variation of the genus clustered in three groups that were consistent with the three morphospecies. Our demographic model predicted a scenario of divergence in absence of gene flow, suggesting that mixed haplotypes may be the result of shared ancestral variation since the divergence of the subtropical-temperate species P. coreodes and P. tertius. In contrast, the tropical species P. arthuri was highly differentiated from the other two in all tests of genetic structure, and consistently, the Monmonier's algorithm identified a clear geographical barrier that separates this species from P. coreodes and P. tertius. CONCLUSIONS: We found three genetically structured lineages within Psammolestes that diverged in absence of gene flow in the late Miocene. This result supports a scenario of species formation driven by geographical isolation rather than by divergence in the face of gene flow associated with climatic oscillations in the Pleistocene. Also, we identified the Amazon basin as a climatic barrier that separates tropical from subtropical-temperate species, thus promoting allopatric speciation after long range dispersion. Finally, each species of Psammolestes occupies different climatic niches suggesting that niche conservatism is not crucial for species differentiation. These findings influence the current vector surveillance programs of Chagas disease in the region.
Assuntos
Doença de Chagas , Reduviidae , Triatominae , Animais , Doença de Chagas/genética , Ecossistema , Filogenia , Reprodutibilidade dos TestesRESUMO
In Heliconius butterflies, wing colour pattern diversity and scale types are controlled by a few genes of large effect that regulate colour pattern switches between morphs and species across a large mimetic radiation. One of these genes, cortex, has been repeatedly associated with colour pattern evolution in butterflies. Here we carried out CRISPR knockouts in multiple Heliconius species and show that cortex is a major determinant of scale cell identity. Chromatin accessibility profiling and introgression scans identified cis-regulatory regions associated with discrete phenotypic switches. CRISPR perturbation of these regions in black hindwing genotypes recreated a yellow bar, revealing their spatially limited activity. In the H. melpomene/timareta lineage, the candidate CRE from yellow-barred phenotype morphs is interrupted by a transposable element, suggesting that cis-regulatory structural variation underlies these mimetic adaptations. Our work shows that cortex functionally controls scale colour fate and that its cis-regulatory regions control a phenotypic switch in a modular and pattern-specific fashion.
Heliconius butterflies have bright patterns on their wings that tell potential predators that they are toxic. As a result, predators learn to avoid eating them. Over time, unrelated species of butterflies have evolved similar patterns to avoid predation through a process known as Müllerian mimicry. Worldwide, there are over 180,000 species of butterflies and moths, most of which have different wing patterns. How do genes create this pattern diversity? And do butterflies use similar genes to create similar wing patterns? One of the genes involved in creating wing patterns is called cortex. This gene has a large region of DNA around it that does not code for proteins, but instead, controls whether cortex is on or off in different parts of the wing. Changes in this non-coding region can act like switches, turning regions of the wing into different colours and creating complex patterns, but it is unclear how these switches have evolved. Butterfly wings get their colour from tiny structures called scales, which each have their own unique set of pigments. In Heliconius butterflies, there are three types of scales: yellow/white scales, black scales, and red/orange/brown scales. Livraghi et al. used a DNA editing technique called CRISPR to find out whether the cortex gene affects scale type. First, Livraghi et al. confirmed that deleting cortex turned black and red scales yellow. Next, they used the same technique to manipulate the non-coding DNA around the cortex gene to see the effect on the wing pattern. This manipulation turned a black-winged butterfly into a butterfly with a yellow wing band, a pattern that occurs naturally in Heliconius butterflies. The next step was to find the mutation responsible for the appearance of yellow wing bands in nature. It turns out that a bit of extra genetic code, derived from so-called 'jumping genes', had inserted itself into the non-coding DNA around the cortex gene, 'flipping' the switch and leading to the appearance of the yellow scales. Genetic information contains the instructions to generate shape and form in most organisms. These instructions evolve over millions of years, creating everything from bacteria to blue whales. Butterfly wings are visual evidence of evolution, but the way their genes create new patterns isn't specific to butterflies. Understanding wing patterns can help researchers to learn how genetic switches control diversity across other species too.
Assuntos
Borboletas/genética , Pigmentos Biológicos/genética , Asas de Animais/fisiologia , Animais , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Cor , FenótipoRESUMO
In this work, the affective state of users in virtual learning environments is assessed/recognized in terms of continuous arousal and valence dimensions, making use of multimodal information (audio, text and video), whenever any of these modalities are available. In general, virtual learning environments where these three modalities are all the time, are not common; at some moments only the video modality is available, while in others only text or/and video and/or audio. Different approaches using feature-level fusion and decision-level fusion are proposed for multimodal recognition with missing data. Recognizing according to available modalities is studied following the ideas of dropout from neural networks and of variable input length from recurrent neural networks. This proposal is innovative because it represents emotions in the continuous space, which is not common in virtual education; and makes use of the available modalities in a virtual environment in a given moment, which is very common in virtual learning environments because the people are not speaking or writing all the time.
RESUMO
Speciation is facilitated when traits under divergent selection also act as mating cues. Fluctuations in sensory conditions can alter signal perception independently of adaptation to the broader sensory environment, but how this fine-scale variation may constrain or promote behavioural isolation has received little attention. The warning patterns of Heliconius butterflies are under selection for aposematism and act as mating cues. Using computer vision, we extracted behavioural data from 1481 h of video footage, for 387 individuals. We show that the putative hybrid species H. heurippa and its close relative H. timareta linaresi differ in their response to divergent warning patterns, but that these differences are strengthened with increased local illuminance. Trials with live individuals reveal low-level assortative mating that is sufficiently explained by differences in visual attraction. Finally, results from hybrid butterflies are consistent with linkage between a major warning pattern gene and the corresponding behaviour, though the differences in behaviour we observe are unlikely to cause rapid reproductive isolation as predicted under a model of hybrid trait speciation. Overall, our results reveal that the contribution of ecological mating cues to reproductive isolation may depend on the immediate sensory conditions during which they are displayed to conspecifics.
Assuntos
Borboletas , Animais , Borboletas/genética , Especiação Genética , Fenótipo , Reprodução , Isolamento ReprodutivoRESUMO
PURPOSE: The purpose of this study was to examine the association of REBOA and mortality in a group of patients with penetrating trauma to the torso, treated in a level-I trauma center from Colombia. METHODS: In a retrospective cohort study, patients with penetrating trauma, requiring emergency surgery, and treated between 2014 and 2018, were included. The decision to use or not use REBOA during emergent surgery was based on individual surgeon's opinion. A propensity score (PS) was calculated after adjusting for age, clinical signs on admission (systolic blood pressure, cardiac rate, Glasgow coma scale), severe trauma in thorax and abdomen, and the presence of non-compressive torso hemorrhage. Subsequently, logistic regression for mortality was adjusted for the number of red blood cells (RBC) transfused within the first six hours after admission, injury severity score (ISS), and quintiles of PS. RESULTS: We included 345 patients; 28 of them (8.1%) were treated with REBOA. Crude mortality rates were 17.9% (5 patients) in REBOA group and 15.3% (48 patients) in control group (p = 0.7). After controlling for RBC transfused, ISS, and the PS, the odds of death in REBOA group was 78% lower than that in the control group (odds ratio [OR] 0.20, 95% confidence interval [95%CI] 0.05-0.77, p = 0.01). CONCLUSION: We found that, when compared to no REBOA use, patients treated with REBOA had lower risk-adjusted odds of mortality. These findings should be interpreted with caution and confirmed in future comparative studies, if possible.