Divergent sensory and immune gene evolution in sea turtles with contrasting demographic and life histories.

Sea turtles represent an ancient lineage of marine vertebrates that evolved from terrestrial ancestors over 100 Mya. The genomic basis of the unique physiological and ecological traits enabling these species to thrive in diverse marine habitats remains largely unknown. Additionally, many populations have drastically declined due to anthropogenic activities over the past two centuries, and their recovery is a high global conservation priority. We generated and analyzed high-quality reference genomes for the leatherback (Dermochelys coriacea) and green (Chelonia mydas) turtles, representing the two extant sea turtle families. These genomes are highly syntenic and homologous, but localized regions of noncollinearity were associated with higher copy numbers of immune, zinc-finger, and olfactory receptor (OR) genes in green turtles, with ORs related to waterborne odorants greatly expanded in green turtles. Our findings suggest that divergent evolution of these key gene families may underlie immunological and sensory adaptations assisting navigation, occupancy of neritic versus pelagic environments, and diet specialization. Reduced collinearity was especially prevalent in microchromosomes, with greater gene content, heterozygosity, and genetic distances between species, supporting their critical role in vertebrate evolutionary adaptation. Finally, diversity and demographic histories starkly contrasted between species, indicating that leatherback turtles have had a low yet stable effective population size, exhibit extremely low diversity compared with other reptiles, and harbor a higher genetic load compared with green turtles, reinforcing concern over their persistence under future climate scenarios. These genomes provide invaluable resources for advancing our understanding of evolution and conservation best practices in an imperiled vertebrate lineage.

Breathing Air and Living Underwater: Molecular Evolution of Genes Related to Antioxidant Response in Cetaceans and Pinnipeds.

Cetaceans and pinnipeds are lineages of mammals that have independently returned to the aquatic environment, acquiring varying degrees of dependence on it while sharing adaptations for underwater living. Here, we focused on one critical adaptation from both groups, their ability to withstand the ischemia and reperfusion experienced during apnea diving, which can lead to the production of reactive oxygen species (ROS) and subsequent oxidative damage. Previous studies have shown that cetaceans and pinnipeds possess efficient antioxidant enzymes that protect against ROS. In this study, we investigated the molecular evolution of key antioxidant enzyme genes (CAT, GPX3, GSR, PRDX1, PRDX3, and SOD1) and the ROS-producing gene XDH, in cetaceans and pinnipeds lineages. We used the ratio of non-synonymous (dN) to synonymous (dS) substitutions as a measure to identify signatures of adaptive molecular evolution in these genes within and between the two lineages. Additionally, we performed protein modeling and variant impact analyzes to assess the functional consequences of observed mutations. Our findings revealed distinct selective regimes between aquatic and terrestrial mammals in five of the examined genes, including divergences within cetacean and pinniped lineages, between ancestral and recent lineages and between crowns groups. We identified specific sites under positive selection unique to Cetacea and Pinnipedia, with one site showing evidence of convergent evolution in species known for their long and deep-diving capacities. Notably, many sites under adaptive selection exhibited radical changes in amino acid properties, with some being damaging mutations in human variations, but with no apparent detrimental impacts on aquatic mammals. In conclusion, our study provides insights into the adaptive changes that have occurred in the antioxidant systems of aquatic mammals throughout their evolutionary history. We observed both distinctive features within each group of Cetacea and Pinnipedia and instances of convergence. These findings highlight the dynamic nature of the antioxidant system in response to challenges of the aquatic environment and provide a foundation for further investigations into the molecular mechanisms underlying these adaptations.

Integrative species delimitation uncovers hidden diversity within the Pithecopus hypochondrialis species complex (Hylidae, Phyllomedusinae) and its phylogeography reveals Plio-Pleistocene connectivity among Neotropical savannas.

Despite their limited vagility and pronounced habitat heterogeneity in the tropics, many anuran species have unexpectedly extensive geographic ranges. One prominent example of this phenomenon is Pithecopus hypochondrialis, which is found in the Cerrado, Guianan savanna, and Llanos domains, as well as isolated tracts of savanna and open habitat within the Amazon Forest. The present study employs an integrative species delimitation approach to test the hypothesis that P. hypochondrialis is in fact a species complex. We also reconstruct the relationships among the lineages delimited here and other Pithecopus species. In this study, we employ Ecological Niche Modelling (ENM) and spatiotemporal phylogeographic reconstruction approaches to evaluate a multitude of scenarios of connectivity across the Neotropical savannas. We identified three divergent lineages, two of which have been described previously. The lineages were allocated to a lowland Pithecopus clade, although the relationships among these lineages are weakly supported. Both the ENM and the phylogeographic reconstruction highlight the occurrence of periods of connectivity among the Neotropical savannas over the course of the Pliocene and Pleistocene epochs. These processes extended from eastern Amazonia to the northern coast of Brazil. The findings of the present study highlight the presence of hidden diversity within P. hypochondrialis, and reinforce the need for a comprehensive taxonomic review. These findings also indicate intricate and highly dynamic patterns of connectivity across the Neotropical savannas that date back to the Pliocene.

Molecular Footprints on Osmoregulation-Related Genes Associated with Freshwater Colonization by Cetaceans and Sirenians.

The genetic basis underlying adaptive physiological mechanisms has been extensively explored in mammals after colonizing the seas. However, independent lineages of aquatic mammals exhibit complex patterns of secondary colonization in freshwater environments. This change in habitat represents new osmotic challenges, and additional changes in key systems, such as the osmoregulatory system, are expected. Here, we studied the selective regime on coding and regulatory regions of 20 genes related to the osmoregulation system in strict aquatic mammals from independent evolutionary lineages, cetaceans, and sirenians, with representatives in marine and freshwater aquatic environments. We identified positive selection signals in genes encoding the protein vasopressin (AVP) in mammalian lineages with secondary colonization in the fluvial environment and in aquaporins for lineages inhabiting the marine and fluvial environments. A greater number of sites with positive selection signals were found for the dolphin species compared to the Amazonian manatee. Only the AQP5 and AVP genes showed selection signals in more than one independent lineage of these mammals. Furthermore, the vasopressin gene tree indicates greater similarity in river dolphin sequences despite the independence of their lineages based on the species tree. Patterns of distribution and enrichment of Transcription Factors in the promoter regions of target genes were analyzed and appear to be phylogenetically conserved among sister species. We found accelerated evolution signs in genes ACE, AQP1, AQP5, AQP7, AVP, NPP4, and NPR1 for the fluvial mammals. Together, these results allow a greater understanding of the molecular bases of the evolution of genes responsible for osmotic control in aquatic mammals.

A phylogenetic review of cancer resistance highlights evolutionary solutions to Peto's Paradox.

Cancer is a genetic disease present in all complex multicellular lineages. Finding ways to eliminate it is a goal of a large part of the scientific community and nature itself. Early, scientists realized that the cancer incidence at the species level was not related to the number of cells or lifespan, a phenomenon called Peto's Paradox. The interest in resolving this paradox triggered a growing interest in investigating the natural strategies for cancer suppression hidden in the animal's genomes. Here, we gathered information on the main mechanisms that confer resistance to cancer, currently described for lineages that have representatives with extended longevity and large body sizes. Some mechanisms to reduce or evade cancer are common and shared between lineages, while others are species-specific. The diversity of paths that evolution followed to face the cancer challenge involving coding, regulatory, and structural aspects of genomes is astonishing and much yet lacks discovery. Multidisciplinary studies involving oncology, ecology, and evolutionary biology and focusing on nonmodel species can greatly expand the frontiers of knowledge about cancer resistance in animals and may guide new promising treatments and prevention that might apply to humans.

Latitudinal diversity gradient and cetaceans from the perspective of MHC genes.

Pathogen diversity is a key source of selective pressure on immune system genes, shaping molecular evolution mainly on widely distributed or migratory organisms such as cetaceans. Here, we investigated the effects of latitudinal span migration, different biomes occupation, and pathogen-mediated selection on MHC DQB locus divergence on cetaceans. We applied some evolutionary genetics methods using a dataset of 15 species and 121 sequences, and we found a trend on greater MHC divergence on tropical species when compared with either temperate or migratory species. In addition, oceanic cetaceans exhibit greater MHC divergence. Here, we show that, despite there was a correlation between the diversity of MHC DQB alleles with the distribution of organisms, the pattern of diversity found is not completely explained by pathogenic pressure, suggesting that other factors must be investigated for a better understanding of the processes related to the diversity of MHC in cetaceans.

Cryptic diversity in Brazilian endemic monkey frogs (Hylidae, Phyllomedusinae, Pithecopus) revealed by multispecies coalescent and integrative approaches.

Even though Brazil is the world leader in amphibian diversity, a significant part of its richness remains unknown or hidden under cryptic taxa. Here, we used model-based species delimitation in an integrative taxonomic approach, by gathering molecular and morphometric data to assess cryptic taxa within the monkey frogs Pithecopus rohdei, from the Atlantic Forest, and P. megacephalus, from campos rupestres ecosystem. We sampled one mitochondrial, five nuclear loci, and 18 morphometric variables. Using species-delimitation methods with genetic and morphometric data, we recovered five divergent lineages within P. rohdei and no cryptic lineages were recovered for P. megacephalus. Morphometric data show differentiation only for one of the candidate species revealed by the delimitation approaches, suggesting that individuals from Doce River basin constitute a putative species for formal taxonomic description. The time-calibrated mtDNA tree shows that P. rohdei complex lineages began to diverge in late Miocene. However, dates from the multilocus species tree are more recent, occurring in Pleistocene, and suggesting their persistence in refuges of forest and sky islands within the Atlantic Forest biome. The existence of cryptic taxa within P. rohdei is, therefore, relevant for planning conservation strategies for this species complex in the Atlantic Forest biodiversity hotspot.

The molecular evolution of genes previously associated with large sizes reveals possible pathways to cetacean gigantism.

Cetaceans are a group of aquatic mammals with the largest body sizes among living animals, including giant representatives such as blue and fin whales. To understand the genetic bases of gigantism in cetaceans, we performed molecular evolutionary analyses on five genes (GHSR, IGF2, IGFBP2, IGFBP7, and EGF) from the growth hormone/insulin-like growth factor axis, and four genes (ZFAT, EGF, LCORL, and PLAG1) previously described as related to the size of species evolutionarily close to cetaceans, such as pigs, cows, and sheep. Our dataset comprised 19 species of cetaceans, seven of which are classified as giants because they exceed 10 m in length. Our results revealed signs of positive selection in genes from the growth hormone/insulin-like growth factor axis and also in those related to body increase in cetacean-related species. In addition, pseudogenization of the EGF gene was detected in the lineage of toothless cetaceans, Mysticeti. Our results suggest the action of positive selection on gigantism in genes that act both in body augmentation and in mitigating its consequences, such as cancer suppression when involved in processes such as division, migration, and cell development control.

The evolutionary history of manatees told by their mitogenomes.

The manatee family encompasses three extant congeneric species: Trichechus senegalensis (African manatee), T. inunguis (Amazonian manatee), and T. manatus (West Indian manatee). The fossil record for manatees is scant, and few phylogenetic studies have focused on their evolutionary history. We use full mitogenomes of all extant manatee species to infer the divergence dates and biogeographical histories of these species and the effect of natural selection on their mitogenomes. The complete mitochondrial genomes of T. inunguis (16,851 bp), T. senegalensis (16,882 bp), and T. manatus (16,882 bp), comprise 13 protein-coding genes, 2 ribosomal RNA genes (rRNA - 12S and 16S), and 22 transfer RNA genes (tRNA), and (D-loop/CR). Our analyses show that the first split within Trichechus occurred during the Late Miocene (posterior mean 6.56 Ma and 95% HPD 3.81-10.66 Ma), followed by a diversification event in the Plio-Pleistocene (posterior mean 1.34 Ma, 95% HPD 0.1-4.23) in the clade composed by T. inunguis and T. manatus; T. senegalensis is the sister group of this clade with higher support values (pp > 0.90). The branch-site test identified positive selection on T. inunguis in the 181st position of the ND4 amino acid gene (LRT = 6.06, p = 0.0069, BEB posterior probability = 0.96). The ND4 gene encodes one subunit of the NADH dehydrogenase complex, part of the oxidative phosphorylation machinery. In conclusion, our results provide novel insight into the evolutionary history of the Trichechidae during the Late Miocene, which was influenced by geological events, such as Amazon Basin formation.

The role of selection in the evolution of marine turtles mitogenomes.

Sea turtles are the only extant chelonian representatives that inhabit the marine environment. One key to successful colonization of this habitat is the adaptation to different energetic demands. Such energetic requirement is intrinsically related to the mitochondrial ability to generate energy through oxidative phosphorylation (OXPHOS) process. Here, we estimated Testudines phylogenetic relationships from 90 complete chelonian mitochondrial genomes and tested the adaptive evolution of 13 mitochondrial protein-coding genes of sea turtles to determine how natural selection shaped mitochondrial genes of the Chelonioidea clade. Complete mitogenomes showed strong support and resolution, differing at the position of the Chelonioidea clade in comparison to the turtle phylogeny based on nuclear genomic data. Codon models retrieved a relatively increased dN/dS (ω) on three OXPHOS genes for sea turtle lineages. Also, we found evidence of positive selection on at least three codon positions, encoded by NADH dehydrogenase genes (ND4 and ND5). The accelerated evolutionary rates found for sea turtles on COX2, ND1 and CYTB and the molecular footprints of positive selection found on ND4 and ND5 genes may be related to mitochondrial molecular adaptation to stress likely resulted from a more active lifestyle in sea turtles. Our study provides insight into the adaptive evolution of the mtDNA genome in sea turtles and its implications for the molecular mechanism of oxidative phosphorylation.

Efecto de talleres de técnica de cepillado monitoreados y supervisados con la técnica "ver-repetir" sobre higiene oral en niños con discapacidad auditiva

Introducción. La salud bucodental de poblaciones vulnerables como aquellas con discapacidad auditiva se enfrenta a barreras de salud por la falta de habilidad para la comunicación resultando en una alta prevalencia de caries, enfermedad periodontal y pérdida dentaria. Objetivo. Disminuir el Índice de O´Leary posterior a talleres de técnica de cepillado monitoreados y supervisados con la técnica "ver-repetir". Materiales y Métodos. Estudio de intervención en estudiantes de una escuela para personas con discapacidad auditiva de Asunción-Paraguay, durante el 2022-2023. Los participantes recibieron entrenamiento de cepillado con la técnica de Bass en modelos y maquetas previo a cada sesión de cepillado. En cada sesión se proveyó a cada participante de cepillo y pasta dental. Se instruyó a padres y maestros para fomentar la técnica en el hogar y en la escuela. Se estableció el Índice de O´Leary previa aplicación de una sustancia reveladora de placa bacteriana. Resultados. Participaron del estudio, 46 niñas y 25 varones entre 4 a 13 años; 12 con dentición temporaria, 41 mixta y 18 permanente. Se realizaron 11 sesiones, siendo 8 la mediana de participación. El índice de O´leary fue al inicio 81,86% ± 26,09% que se redujo significativamente a 11,69% ± 3,94%; en el 100% se redujo a menos de 25%. Los primeros molares permanentes inicialmente cariados fueron restaurados y permanecieron sin recidivas hasta el final. Conclusión. La cantidad de placa bacteriana oral en niños con discapacidad auditiva se puede mantener bajo control siguiendo estrategias de higiene que sean supervisadas y monitoreadas.

Introduction. The oral health of vulnerable populations such as the hearing-impaired face barriers due to lack of communication skills resulting in a high prevalence of caries, periodontal disease and tooth loss. Objective. To decrease O'Leary index after monitored and supervised brushing technique workshops with the "see-repeat" technique. Materials and Methods. Intervention study in students of a school for people with hearing disabilities in Asunción-Paraguay, during 2022-2023. The participants received brushing training with the Bass technique on models and mock-ups prior to each brushing session. In each session, each participant was provided with a toothbrush and toothpaste. Parents and teachers were instructed to promote the technique at home and at school. The O'Leary Index was established after applying a substance that reveals bacterial plaque. Results. 46 girls and 25 boys between 4 and 13 years old participated in the study; 12 with temporary teeth, 41 mixed and 18 permanent. 11 sessions were held, with a median participation of 8. The O'leary index was 81.86% ± 26.09% at the beginning, which was significantly reduced to 11.69% ± 3.94%; in 100% it was reduced to less than 25%. The initially decayed first permanent molars were restored and remained recurrence-free until the end. Conclusion. The amount of oral bacterial plaque in hearing impaired children can be kept under control by following hygiene strategies that are supervised and monitored.

Prevalencia del desarrollo de entesofito en la Protuberancia Occipital Externa en población de paraguayos / Prevalence of enthesophyte development in External Occipital Protuberance in Paraguayan population

Introducción.La Protuberancia Occipital Externa (POE) es una superficie convexa y lisa que tradicionalmente no presenta ningún tipo de irregularidades. La aparición de un entesofito en individuos ha llamado la atención de los investigadores. Objetivo.Determinar la prevalencia, longitud, edad y sexo de una exostosis en forma de gancho desarrollada a nivel de la POE. Metodología.Estudio observacional descriptivo realizado en radiografías laterales de cráneo de individuos jóvenes. De 5065 radiografías, 4017 radiografías cumplieron con los criterios. Se procedió a la detección de la presencia de un gancho óseo en la POE y su medición. Resultados.Se incluyeron personas de ambos sexos entre 13 a 45 años: 2902 mujeres y 1115 varones. De las 4017 radiografías observadas, el 67% presentó la excrecencia en la POE, con rangos desde 5 a 24 mm en longitud, 511 tenían una longitud de 5 mm o mayor, 903 entre 9 a 12 mm de longitud y 253 de 13 a 24mm. Se observó enmayor proporción en el sexo masculino que el femenino(68% vs 32%). En los individuos de 40 años y más, solo un paciente de sexo masculino mostró la presencia del entesofito. Conclusión.Se ha encontrado una alta frecuencia del desarrollo de una protuberancia ósea a nivel del POE en jóvenes y adultos jóvenesde sexo masculino. Este es el primer estudio de este tipo realizado en la población del Paraguay. Para comprender la razón del desarrollo de esta excrecencia ósea, es necesario ampliar el área de investigación. Palabras Clave:ganchos óseos;protuberancia; exostosis; entesopatía.

Introduction.The external occipital protuberance (EOP) is a smooth convex surface which commonly does not present any type of irregularities. The development of an enthesophyte in young population has attracted the attention of researchers. Objective.To determine the prevalence, size, age, and sex of individuals with bony projections that resembles a hook developed in EOP. Methodology.Descriptive observational study. 5065 lateral skull x-rays were observed. 4017 fulfilled all the criteria. The x-rays were reviewed for the presence of a bony excrescence in EOP, and they were measured. Results. From a both sexes population between 13 to 45 years old 2902 were female and 1115 were male. 67% X-rays presented the enthesophyte ranging from 5 ­24mm in length. 511 out of 1667 had an enthesophyte at or above 5 mm. There were 903 patients with an enthesophyte ranging from 9 ­12 mm in length and 254 had the protuberance ranging from 13 ­24 mm. Statistically significant range of 68% vs 32% between males and females were observed. From individuals of 40 years and above, just 1 male patient out of 32 showedthe enthesophyte. Conclusion.Significant association with the development of a bony protuberance at the POE in young and young adult male population has been found. This is the first study of this type in Paraguayan individuals. To expand the field of studies, future research is needed to better examine and understand the reason forthe development of this bony excrescence. Key words:bone hooks; protuberance;exostoses; enthesopathies.

Economic evaluation of duloxetine as a first-line treatment for painful diabetic peripheral neuropathy in Mexico.

OBJECTIVE: To perform an economic evaluation of duloxetine, pregabalin, and both branded and generic gabapentin for managing pain in patients with painful diabetic peripheral neuropathy (PDPN) in Mexico. RESEARCH DESIGN AND METHODS: The analysis was conducted using a 3-month decision model, which compares duloxetine 60 mg once daily (DUL), pregabalin 150 mg twice daily (PGB), and gabapentin 600 mg three-times daily (GBP) for PDPN patients with moderate-to-severe pain. A systematic review was performed and placebo-adjusted risk ratios for achieving good pain relief (GPR), adverse events (AE), and withdrawal owing to intolerable AE were calculated. Direct medical costs included drug acquisition and additional visits due to lack of efficacy (poor pain relief) or intolerable AE. Unit costs were taken from local sources. Adherence rates were used to estimate the expected drug costs. All costs are expressed in 2010 Mexican Pesos (MXN). Utility values drawn from published literature were applied to health states. The proportion of patients with GPR and quality-adjusted life years (QALY) were assessed. RESULTS: Branded-GBP was dominated by all the other options. PGB was more costly and less effective than DUL. Compared with branded-GBP and PGB, DUL led to savings of 1.01 and 1.74 million MXN (per 1000 patients). The incremental cost per QALY gained with DUL used instead of generic-GBP was $102 433 MXN. This amount is slightly lower than the estimated gross domestic product per capita in Mexico for 2010. During a second-order Monte Carlo simulation, DUL had the highest probability of being cost-effective (61%), followed by generic-GBP (25%) and PGB (14%). LIMITATIONS: Study limitations include a short timeframe and using data from different dosage schemes for GBP and PGB. CONCLUSIONS: This study suggests that DUL provides overall savings and better health outcomes compared with branded-GBP and PGB. Administering DUL rather than generic-GBP is a cost-effective intervention to manage PDPN in Mexico.

Hipersensibilidad dentaria: causas y tratamientos / Tooth Hypersensitivity: Causes and treatments

La sensibilidad dentaria es la respuesta dolorosa de la dentina ante ciertos estímulos normales, térmicos químicos o táctiles y ha sido desde siempre uno de los problemas más desagradables que puede padecer un individuo. El propósito de este trabajo es conocer las posibles causas que producen la sensibilidad dentaria, describir tanto sus teorías o sus probables hipótesis, así como también dar un repaso a los múltiples métodos estudiados y decriptos que se han propuesto a través de los años para sus tratamieinto.