Population Structuring Research Articles

The Comprehension of Grammatical Structures in a Pediatric Population with ASD and Epilepsy: A Comparative Study.

Autism Spectrum Disorder (ASD) and epilepsy represent a comorbidity that negatively influences the proper development of linguistic competencies, particularly in receptive language, in the pediatric population. This group displays impairments in the auditory comprehension of both simple and complex grammatical structures, significantly limiting their performance in language-related activities, hampering their integration into social contexts, and affecting their quality of life. The main objective of this study was to assess auditory comprehension of grammatical structures in individuals with ASD and epilepsy and compare the results among the three groups. A non-experimental cross-sectional study was designed, including a total of 170 participants aged between 7 and 9 years, divided into three groups: a group with ASD, a group with epilepsy, and a comorbid group with both ASD and epilepsy (ASDEP). The comprehension of grammatical structures was assessed using the CEG and CELF-5 instruments. Statistical analyses included MANOVA and ANOVA to compare scores between groups to verify associations between study variables. The results indicate that the group with ASD and epilepsy performed worse compared to the ASD and epilepsy-only groups, respectively. Additionally, a significant and directly proportional association was observed among all variables within the measures of grammatical structure comprehension. The neurological damage caused by epilepsy in the pediatric population with ASD leads to difficulties in understanding oral language. This level of functioning significantly limits the linguistic performance of these children, negatively impacting their quality of life and the development of core language skills.

Genetic structuring of Fishers in British Columbia, Canada: implications for population conservation and management

Abstract In the westernmost Canadian province of British Columbia, fishers (Pekania pennanti) occur in low-elevation forested ecosystems in the central and northern portions of the province, with several substantial mountain ranges and rivers bisecting this distribution. The effect of these geographic features on gene flow and population structuring is unknown and may contribute to fishers differentiating into 2 or more populations within the province. To better understand population structuring within the range of fishers in British Columbia, we collected tissue samples from 491 fishers from throughout the province and evaluated variation of neutral genetic markers using a 385-base pair section of the mitochondrial DNA control region and 13 microsatellite loci. Fishers appeared to be genetically structured as hierarchical stepping-stone populations where an upper hierarchical level of genetic partitioning resulted in 2 populations at the provincial scale, with 3 subpopulations occurring in the central interior region. We observed gene flow of 2 to 5 migrants per generation between the 2 upper populations, which was substantially less than the 90 migrants per generation estimated as needed to maintain genetic homogeneity. This resulted in differentiated upper populations (haplotype FST = 0.272, microsatellite FST = 0.049) characterized by relatively low Ne (Columbian population = 252, 95% CI = 185 to 332; Boreal population [British Columbia only] = 136, 95% CI = 92 to 234). The consequence of low gene flow and resultant population structuring is that the Columbian population likely receives relatively little genetic and demographic support from other populations and, combined with precipitous recent declines in its numbers, puts this population at heightened conservation risk. As a result, swift and effective actions are needed to conserve this vulnerable population of fishers.

The black goby Gobius niger Linnaeus, 1758 in the Marchica Lagoon (Alboran Sea, Morocco): spatio-temporal distribution, its environmental drivers, and the site-related footprint

Gobies (Gobiidae) are well represented in the Marchica Lagoon on the Moroccan Mediterranean coast, both in terms of species richness and in terms of abundance, with the black goby, Gobius niger Linnaeus, 1758, being the dominant species. The present study aims to examine (1) the spatial and temporal distribution of G. niger and its environmental drivers in the lagoon and (2) the potential lagoon-related footprint using morphometric, genetic, and parasitological proxies. Systematic monthly sampling covering the whole lagoon basin performed between October 2015 and September 2016 revealed a year-long presence of G. niger throughout the lagoon with significantly low densities in winter. The highest abundances were recorded in the shallow bottoms of the lagoon’s inner margins on a variety of substrates (mud, muddy-sand, sandy-mud, and fine sand) mostly covered by macroalgae and/or seagrass meadows. Depth was revealed to be the most important predictor of the distribution of the black goby in the lagoon. It should, however, be regarded as a variable that acts synergistically with other factors, such as temperature, vegetation cover, and the sediment’s mean grain size. Comparison of black goby populations from the lagoon with their conspecifics from the adjacent Mediterranean coast of Morocco revealed that specimens caught at sea are larger than those of the lagoon population. Of the 180 gobies investigated, not a single one hosted the parasites we targeted in the parasitological approach, monogenean flatworms. The absence of population structuring, low genetic diversity, and the presence of common haplotypes indicate no apparent restriction in the gene flow between the two populations. Therefore, the observed morphometric differences seem to be due to external environmental conditions rather than genetic differences.

Genetic structuring and species boundaries in the Atlantic stony coral Favia (Scleractinia, Faviidae)

AbstractScleractinian corals are the main modern builders of coral reefs, which are major hot spots of marine biodiversity. Southern Atlantic reef corals are understudied compared to their Caribbean and Indo‐Pacific counterparts and many hypotheses about their population dynamics demand further testing. We employed thousands of single nucleotide polymorphisms (SNPs) recovered via ezRAD to characterize genetic population structuring and species boundaries in the amphi‐Atlantic hard coral genus Favia. Coalescent‐based species delimitation (BFD* – Bayes Factor Delimitation) recovered F. fragum and F. gravida as separate species. Although our results agree with depth‐related genetic structuring in F. fragum, they did not support incipient speciation of the ‘tall’ and ‘short’ morphotypes. The preferred scenario also revealed a split between two main lineages of F. gravida, one from Ascension Island and the other from Brazil. The Brazilian lineage is further divided into a species that occurs throughout the Northeastern coast and another that ranges from the Abrolhos Archipelago to the state of Espírito Santo. BFD* scenarios were corroborated by analyses of SNP matrices with varying levels of missing data and by a speciation‐based delimitation approach (DELINEATE). Our results challenge current notions about Atlantic reef corals because they uncovered surprising genetic diversity in Favia and rejected the long‐standing hypothesis that Abrolhos Archipelago may have served as a Pleistocenic refuge during the last glaciations.

The COVID-19 Pandemic Impact of Hospital Wastewater on Aquatic Systems in Bucharest

The COVID-19 pandemic reshaped the global response to a pandemic, including the way of using chemical compounds such as disinfectants and antibiotics. The large-scale use of antibiotics and disinfectants during the COVID-19 pandemic caused environmental pressure not only due to the chemicals themselves but also due to their effect on bacterial communities, inducing resistance to chemicals and changing the population structure of bacterial communities, especially in aquatic environments. The dissemination of fecal bacteria, including antibiotic-resistant bacteria, and pathogens from hospital wastewater into the environment, via wastewater treatment plants (WWTPs), triggered the premises of a major public health issue. Rivers flowing through cities are natural streams for WWTP discharges, and they directly bear the impact of anthropic activities, disseminating domestic and industrial pollution over large areas. The aim of the present study was to assess the microbiological bacterial structure of municipal and hospital wastewaters as well as their impact on natural streams, covering the pre-to post-COVID-19 pandemic period of time. The results indicated that the COVID-19 pandemic had a direct impact on hospital wastewater microbiological quality and the environment due to an excessive use of antibiotics and disinfectants. In addition, the constant presence of antibacterial compounds increased the rate of bacterial selection and induced population structural changes in the bacterial communities from aquatic systems.

Population structure and history of North Atlantic Blue whales (Balaenoptera musculus musculus) inferred from whole genome sequence analysis

Knowledge of genetic diversity and structure is essential for developing conservation strategies for endangered species. Blue whales were hunted to near extinction in the mid-twentieth century. Not-withstanding almost 380,000 animals killed globally, much remains unknown about their population structure and migration patterns. Herein, we use whole genome sequencing to elucidate the poorly understood population genetics of North Atlantic (NA) blue whales. We generated a de novo genome assembly for a NA blue whale to analyze 19 other whole genomic sequences and 31 complete mitochondrial genomes. Present-day and historical samples (earliest from 1876) from the Atlantic and Antarctic Oceans were included to understand the impact of whaling on the genetic diversity of this species. We found low but statistically significant population structuring and high genetic diversity. Demographic modeling using fastsimcoal2 rejected an absence of gene flow between eastern and western NA blue whales and suggested an asymmetric west to east gene flow. Introgression estimated using D-statistics between blue and fin whales (Balaenoptera physalus), was observed in all present-day samples. This gene flow was found to be unidirectional from fin whales to blue whales and accounts for ~ 3.5% of the NA blue whale’s genome. Our sequencing and population structure analyses provide a genomic baseline to inform ongoing conservation strategies for this iconic species.

Genomic Architecture Predicts Tree Topology, Population Structuring, and Demographic History in Amazonian Birds.

Geographic barriers are frequently invoked to explain genetic structuring across the landscape. However, inferences on the spatial and temporal origins of population variation have been largely limited to evolutionary neutral models, ignoring the potential role of natural selection and intrinsic genomic processes known as genomic architecture in producing heterogeneity in differentiation across the genome. To test how variation in genomic characteristics (e.g. recombination rate) impacts our ability to reconstruct general patterns of differentiation between species that cooccur across geographic barriers, we sequenced the whole genomes of multiple bird populations that are distributed across rivers in southeastern Amazonia. We found that phylogenetic relationships within species and demographic parameters varied across the genome in predictable ways. Genetic diversity was positively associated with recombination rate and negatively associated with species tree support. Gene flow was less pervasive in genomic regions of low recombination, making these windows more likely to retain patterns of population structuring that matched the species tree. We further found that approximately a third of the genome showed evidence of selective sweeps and linked selection, skewing genome-wide estimates of effective population sizes and gene flow between populations toward lower values. In sum, we showed that the effects of intrinsic genomic characteristics and selection can be disentangled from neutral processes to elucidate spatial patterns of population differentiation.

Stone point variability reveals spatial, chronological and environmental structuring of eastern African Middle Stone Age populations

ABSTRACT Stone points are one of the key features used to define the African Middle Stone Age (MSA). Regional patterns in their shape and size through time have been thought to reflect inter-group interactions and networks of populations and are used to define cultural phases within the MSA. However, eastern Africa does not have distinctive and widely applied chrono-stratigraphic point variants that divide its MSA record, which is often described as being highly variable. This paper presents a metric and geometric morphometric analysis of eastern African MSA points and evaluates potential drivers of variation in them in relation to null models of isolation by distance, time and environment. Approximately half of the shape variance in our sample can be explained by spatial, temporal and environmental differences, as well as by size, indicating a degree of demographic continuity through sustained cultural transmission. A portion of the remaining variance likely represents stylistic differences between assemblages, which are often the subject of interest in archaeological studies. The highly variable nature of the eastern African MSA may reflect the region’s refugial positioning within the continent, with point technology a flexible adaptive system that was dynamically employed across Africa during the MSA depending on varying social and ecological contexts, resulting in the appearance of both ‘generic’ and ‘specific’ tool forms at particular times and places.

Genetic diversity and population structure of the Asian citrus psyllid in China.

The Asian citrus psyllid (ACP) is the main vector of Citrus Huanglongbing, the most damaging citrus disease, causing significant financial losses in the citrus industry. Global warming has expanded the habitat of this pest, allowing it to continue its northward migration to China. Population genetic information of ACP is fundamentally essential for species management. This study investigated the genetic diversity and population structure of Chinese ACP using the mitochondrial cytochrome oxidase subunit I gene by dataset comprised 721 sequences from 27 geographic sites in China. Low haplotype diversity (0.323 ± 0.022) and low nucleotide diversity (0.00071 ± 0.00007) were observed in the entire population, which may indicate recent founder events. Twenty-three haplotypes were identified and clustered into 2 haplogroups: haplogroup I and haplogroup II. Haplogroup II included only 2 unique haplotypes, which occurred exclusively in the Southwest China ACP population. Genetic differentiation analyses were also indicative of Southwest China population was significantly differentiated from the remaining populations. Demographic history analysis showed that ACP population in China has experienced demographic expansion. Our results provided a better understanding of the genetic distribution patterns and structures of ACP populations in China.

A first look at mitochondrial genetic diversity in Miniopterus schreibersii in Serbia

Schreiber?s bent-winged bat Miniopterus schreibersii (Chiroptera) is a widespread, cave-dwelling, regionally migrating species whose genetic diversity was studied throughout its distribution area using mitochondrial and nuclear markers. Previous studies revealed little to no structuring of populations and established Anatolia to be a single refugium during the last glacial maximum. The Balkans were well covered in these studies but usually lacked samples from Serbia. We sequenced the mitochondrial hypervariable region 1 (HV1) gene in M. schreibersii collected at seven sites in Serbia to assess their genetic relatedness to other European and Asia Minor populations and check whether the Balkans exhibit a higher genetic diversity than Western Europe due to its closeness to Anatolia. We recorded nine haplotypes from Serbia, six of which had not been previously reported, with a haplotype diversity of 0.585. The remaining three were shared with individuals from Portugal, Greece, and Turkey. A single most common haplotype was present throughout the species distribution range, pointing to a well-connected population and as indicated by the shape of the haplotype network, a common origin, and a sudden population expansion. Results complement existing data on M. schreibersii having a non-structured population, adding valuable new data from the Balkans supporting the previous hypothesis about its Anatolian origin.

Membrane binding and lipid-protein interaction of the C2 domain from coagulation factor V

Anchoring of coagulation factors to anionic regions of the membrane involves the C2 domain as a key player. The rate of enzymatic reactions of the coagulation factors is increased by several orders of magnitude upon membrane binding. However, the precise mechanisms behind the rate acceleration remain unclear, primarily because of a lack of understanding of the conformational dynamics of the C2-containing factors and corresponding complexes. We elucidate the membrane-bound form of the C2 domain from human coagulation factor V (FV–C2) by characterizing its membrane binding the specific lipid-protein interactions. Employing all-atom molecular dynamics simulations and leveraging the highly mobile membrane-mimetic (HMMM) model, we observed spontaneous binding of FV-C2 to a phosphatidylserine (PS)-containing membrane within 2–25 ns across twelve independent simulations. FV-C2 interacted with the membrane through three loops (spikes 1–3), achieving a converged, stable orientation. Multiple HMMM trajectories of the spontaneous membrane binding provided extensive sampling and ample data to examine the membrane-induced effects on the conformational dynamics of C2 as well as specific lipid-protein interactions. Despite existing crystal structures representing presumed “open” and “closed” states of FV-C2, our results revealed a continuous distribution of structures between these states, with the most populated structures differing from both “open” and “closed” states observed in crystal environments. Lastly, we characterized a putative PS-specific binding site formed by K23, Q48, and S78 located in the groove enclosed by spikes 1–3 (PS-specificity pocket), suggesting a different orientation of a bound headgroup moiety compared to previous proposals based upon analysis of static crystal structures.

Genetic variants and haplotype structures of miRNA host genes in cancer and obesity

Cancer and obesity are two important public health problems. This study aimed to investigate the role of genetic variants and haplotypes of miRNA host genes in cancer and obesity. Data from the catalog of genome-wide association studies (GWAS) were used to find significant variants (index). Then, 1000-genome phase 3 data were used to find haplotypic variants (proxy) associated with these diseases. The candidate variants and haplotypes were identified from proxy and index variants. Finally, SNP function analysis was performed. All GWAS-significant cancer-associated miRNA host gene variants, including MIR4713HG, MIR663AHG, MIR99AHG and MIR4435-2HG, were also significantly associated with obesity. The rs703764 variant was common between cutaneous melanoma and obesity traits in the European population (P ≤ 5E−8). The rs2414098 variant was associated with endometrial cancer (P ≤ 5E-13), and the rs7173595 variant was associated with waist-hip ratio (P ≤ 5E-13) and new CGGCATCA haplotypic located at MIR4713HG was identified in the European population. In addition, the ATCTTGTT haplotype for rs17041868 in MIR4435-2HG was identified to be associated with obesity traits (waist-hip ratio and BMI) in the European population (P ≤ 5E−8). This study found that rs703764 is a common genetic marker between cancer and obesity. The CGGCATCA haplotype is common between endometrial cancer and waist-hip ratio. Also, ATCTTGTT haplotype is associated with obesity traits. These results indicate that the variants and haplotypes of miRNAs host genes play an important role between cancer and obesity in the European population. It is suggested to investigate the effect of these structures in other populations. Communicated by Ramaswamy H. Sarma

Molecular and morphometric data provide evidence of intraspecific variation in shape and pigmentation pattern in Otocinclus cocama (Siluriformes: Loricariidae) across major river drainages.

Otocinclus cocama, a uniquely colored species of the loricariid catfish genus Otocinclus described solely from the type locality in the lower Ucayali River in northern Peru, is reported occurring in the Tigre River, a tributary to the Marañón River that drains a different section of the Andean Mountain range in the western Amazon. Both populations differ in the number of dark bars spanning the flanks of the body, and we investigated whether these morphotypes constitute distinct species. The body shapes of populations from the Tigre and Ucayali rivers were compared using geometric morphometrics. Although principal component analysis detected a broad overlap between populations, multivariate analysis of variance and linear driscriminat analysis revealed a subtle differentiation between the populations of the two hydrographic basins. Average body shape of the Ucayali River population tend to be slightly higher than that of the Tigre River, with the caudal peduncle stretched vertically in the Ucayali population. Multivariate regression of shape and centroid size revealed an allometric effect of 10.7% (p < 0.001), suggesting that the variation between Tigre and Ucayali populations was purely shape variation. Molecular data of coI, cytb, nd2, and 16S mitochondrial genes indicated a nucleotide diversity range from 0.001 to 0.003, and haplotypic diversity range from 0.600 ± 0.11 to 0.79 ± 0.07. The median-joining haplotype network for the concatenated matrix exhibited two divergent haplogroups related to the geographic area and separated by <10 mutational steps. The molecular species delimitation methods based on distance (automatic barcode gap discovery and assemble species by automatic partitioning) recovered two molecular lineages evolving independently, being one of the lineages formed by individuals from both populations. Tree-based methods (generalized mixed Yule coalescent and Bayesian implementation of the Poisson tree process) recovered similar topologies and supported single lineage recognition. Methods of molecular delimitation of species disclosed the high similarity between the two populations of Otocinclus cocama, further supported by the presence of old haplotypes common to both groups which could indicate that the populations still maintain gene flow. Although the morphological data reveal a subtle variation between both river basins, the molecular data suggest a weak population structuration based on hydrographic areas, but not different species lineages, therefore Otocinclus cocama is composed of a single lineage with two distinct morphotypes.

Mimosa Kinetic Façade: Bio-Inspired Ventilation Leveraging the Mimosa Pudica Mechanism for Enhanced Indoor Air Quality.

In light of pressing global health concerns, the significance of indoor air quality in densely populated structures has been emphasized. This research introduces the Mimosa kinetic façade, an innovative design inspired by the adaptive responsiveness of the Mimosa plant to environmental stimuli. Traditional static architectural façades often hinder natural ventilation, leading to diminished air quality with potential health and cognitive repercussions. The Mimosa kinetic façade addresses these challenges by enhancing effective airflow and facilitating the removal of airborne contaminants. This study evaluates the façade's impact on quality of life and its aesthetic contribution to architectural beauty, utilizing the biomimicry design spiral for a nature-inspired approach. Computational simulations and physical tests were conducted to assess the ventilation capacities of various façade systems, with a particular focus on settings in Bangkok, Thailand. The study revealed that kinetic façades, especially certain patterns, provided superior ventilation compared to static ones. Some patterns prioritized ventilation, while others optimized human comfort during extended stays. Notably, the most effective patterns of the kinetic façade inspired by the Mimosa demonstrated a high air velocity reaching up to 12 m/s, in contrast to the peak of 2.50 m/s in single-sided façades (traditional façades). This highlights the kinetic façade's potential to rapidly expel airborne particles from indoor spaces, outperforming traditional façades. The findings underscore the potential of specific kinetic façade patterns in enhancing indoor air quality and human comfort, indicating a promising future for kinetic façades in architectural design. This study aims to achieve an optimal balance between indoor air quality and human comfort, although challenges remain in perfecting this equilibrium.

Impact of population structure in the estimation of recent historical effective population size by the software GONE

BackgroundEffective population size (Ne) is a crucial parameter in conservation genetics and animal breeding. A recent method, implemented by the software GONE, has been shown to be rather accurate in estimating recent historical changes in Ne from a single sample of individuals. However, GONE estimations assume that the population being studied has remained isolated for a period of time, that is, without migration or confluence of other populations. If this occurs, the estimates of Ne can be heavily biased. In this paper, we evaluate the impact of migration and admixture on the estimates of historical Ne provided by GONE through a series of computer simulations considering several scenarios: (a) the mixture of two or more ancestral populations; (b) subpopulations that continuously exchange individuals through migration; (c) populations receiving migrants from a large source; and (d) populations with balanced systems of chromosomal inversions, which also generate genetic structure.ResultsOur results indicate that the estimates of historical Ne provided by GONE may be substantially biased when there has been a recent mixture of populations that were previously separated for a long period of time. Similarly, biases may occur when the rate of continued migration between populations is low, or when chromosomal inversions are present at high frequencies. However, some biases due to population structuring can be eliminated by conducting population structure analyses and restricting the estimation to the differentiated groups. In addition, disregarding the genomic regions that are involved in inversions can also remove biases in the estimates of Ne.ConclusionsDifferent kinds of deviations from isolation and panmixia of the populations can generate biases in the recent historical estimates of Ne. Therefore, estimation of past demography could benefit from performing population structure analyses beforehand, by mitigating the impact of these biases on historical Ne estimates.

Population age and household structures shape transmission dynamics of emerging infectious diseases: a longitudinal microsimulation approach.

Host population demographics and patterns of host-to-host interactions are important drivers of heterogeneity in infectious disease transmission. To improve our understanding of how population structures and changes therein influence disease transmission dynamics at the individual and population level, we model a dynamic age- and household-structured population using longitudinal microdata drawn from Belgian census and population registers. At different points in time, we simulate the spread of a close-contact infectious disease and vary the age profiles of infectiousness and susceptibility to reflect specific infections (e.g. influenza and SARS-CoV-2) using a two-level mixing model, which distinguishes between exposure to infection in the household and exposure in the community. We find that the strong relationship between age and household structures, in combination with social mixing patterns and epidemiological parameters, shape the spread of an emerging infection. Disease transmission in the adult population in particular is to a large degree explained by differential household compositions and not just household size. Moreover, we highlight how demographic processes alter population structures in an ageing population and how these in turn affect disease transmission dynamics across population groups.

Euclid: Identification of asteroid streaks in simulated images using deep learning

The material composition of asteroids is an essential piece of knowledge in the quest to understand the formation and evolution of the Solar System. Visual to near-infrared spectra or multiband photometry is required to constrain the material composition of asteroids, but we currently have such data, especially in the near-infrared wavelengths, for only a limited number of asteroids. This is a significant limitation considering the complex orbital structures of the asteroid populations. Up to 150 000 asteroids will be visible in the images of the upcoming ESA Euclid space telescope, and the instruments of Euclid will offer multiband visual to near-infrared photometry and slitless near-infrared spectra of these objects. Most of the asteroids will appear as streaks in the images. Due to the large number of images and asteroids, automated detection methods are needed. A non-machine-learning approach based on the Streak Det software was previously tested, but the results were not optimal for short and/or faint streaks. We set out to improve the capability to detect asteroid streaks in Euclid images by using deep learning. We built, trained, and tested a three-step machine-learning pipeline with simulated Euclid images. First, a convolutional neural network (CNN) detected streaks and their coordinates in full images, aiming to maximize the completeness (recall) of detections. Then, a recurrent neural network (RNN) merged snippets of long streaks detected in several parts by the CNN. Lastly, gradient-boosted trees (XGBoost) linked detected streaks between different Euclid exposures to reduce the number of false positives and improve the purity (precision) of the sample. The deep-learning pipeline surpasses the completeness and reaches a similar level of purity of a non-machine-learning pipeline based on the StreakDet software. Additionally, the deep-learning pipeline can detect asteroids 0.25–0.5 magnitudes fainter than StreakDet. The deep-learning pipeline could result in a 50% increase in the number of detected asteroids compared to the StreakDet software. There is still scope for further refinement, particularly in improving the accuracy of streak coordinates and enhancing the completeness of the final stage of the pipeline, which involves linking detections across multiple exposures.

Limited congruence in phylogeographic patterns observed for riverine predacious beetles sharing distribution along the mountain rivers

Riverine predacious beetles (RPB) (Carabidae, Staphylinidae) are highly diverse and numerous elements of riverine ecosystems. Their historical and contemporary distribution and diversity are highly dependent on natural flow regimes and topography of watercourses. Despite broad knowledge of their ecology, data on population genetic diversity and connectivity are lacking. This study aimed to fill this gap in order to solve two principal hypotheses assuming (i) congruence of phylogeographic patterns observed for RPB indicating that they share a common history and the ecological adaptations to the dynamic environment, (ii) genetic structuration of populations according to river basins. The Carpathian populations of four ground beetles and three rove beetles were examined using cytochrome oxidase and arginine kinase sequencing. There are substantial differences in RPB demographic history and current genetic diversity. Star-like phylogeny of Bembidion and complex haplotype networks of Paederus/Paederidus, with some haplotypes being drainage-specific and others found in distant populations, indicate a general lack of isolation by distance. Signs of recent demographic expansion were detected for most RPB with the latest population collapse for some rove beetles. To some extent, migration of examined species has to be limited by watersheds. Observed phylogeographic patterns are essential for correctly understanding RPB meta-population functioning.

Lineage diversification of the Sky Island treefrog Scinax curicica (Anura, Hylidae) in the Espinhaço Mountain Range

Abstract Sky Islands present unique landscapes for organismal evolution because they comprise high mountain peaks separated by low valleys with vastly different environmental conditions. The Espinhaço Mountain Range in eastern Brazil is formed of groups of Sky Islands in the states of Minas Gerais and Bahia. Several phylogeographic studies have discovered strong genetic structure among populations of organisms occupying the campo rupestre (rupestrian fields) in the mountains of the Espinhaço. In this study, we aimed to test the hypothesis of spatio-temporal structuring of populations of Scinax curicica in the campo rupestre of the Espinhaço. We recovered three lineages of S. curicica: one lineage occurs in the north portion of the Espinhaço (North Lineage) in an area called Chapada Diamantina, and other two occur in the south portion of the Espinhaço (South 1 and South 2 Lineages) in Minas Gerais. All three lineages showed stable population sizes through time, probably due to the climatic stability of mountaintop areas, which was supported by ecological niche modelling.

The Spatial Structure and Driving Mechanisms of Multi-Source Networks in the Chengdu–Chongqing Economic Circle of China

The phenomenon of polarized development among regional cities has sparked extensive contemplation and indicated a need for research on multi-source regional networks. However, such research faces two obstacles: the absence of quantitative measurement of differences in network structures and the lack of a thorough examination of the degree of city clustering and the dynamics of community composition in hierarchical networks. Thus, we identified 16 cities in the Chengdu–Chongqing Economic Circle (CCEC) as the spatial units to examine the spatial network structures of population, resources, and transportation and the integrated spatial network structure. Using social network analysis, this paper describes the structural characteristics of the three networks (population, resource, and transportation), followed by an analysis of their collective and hierarchical network clustering characteristics, and explores the driving mechanisms and factors that make up each network model. Our results show the following: (1) All three networks exhibit an “east dense, west sparse” characteristic, but there are differences in the layouts of the core cities in terms of the three networks. (2) The clustering characteristics of the hierarchical networks are more pronounced than those of the overall network. The results of the analysis combined with the network formation mechanisms can help effectively plan the future coordinated development of the CCEC.