Explore the vast range of titles available.

The relative importance of the processes that generate and maintain biodiversity is a major and controversial topic in evolutionary biology with large implications for conservation management. The Atlantic Forest of Brazil, one of the world's richest biodiversity hot spots, is severely damaged by human activities. To formulate an efficient conservation policy, a good understanding of spatial and temporal biodiversity patterns and their underlying evolutionary mechanisms is required. With this aim, we performed a comprehensive phylogeographic study using a low-dispersal organism, the land planarian species Cephaloflexa bergi (Platyhelminthes, Tricladida). Analysing multi-locus DNA sequence variation under the Approximate Bayesian Computation framework, we evaluated two scenarios proposed to explain the diversity of Southern Atlantic Forest (SAF) region. We found that most sampled localities harbour high levels of genetic diversity, with lineages sharing common ancestors that predate the Pleistocene. Remarkably, we detected the molecular hallmark of the isolation-by-distance effect and little evidence of a recent colonization of SAF localities; nevertheless, some populations might result from very recent secondary contacts. We conclude that extant SAF biodiversity originated and has been shaped by complex interactions between ancient geological events and more recent evolutionary processes, whereas Pleistocene climate changes had a minor influence in generating present-day diversity. We also demonstrate that land planarians are an advantageous biological model for making phylogeographic and, particularly, fine-scale evolutionary inferences, and propose appropriate conservation policies.

Chromosomal inversion polymorphism play a major role in the evolutionary dynamics of populations and species because of their effects on the patterns of genetic variability in the genomic regions within inversions. Though there is compelling evidence for the adaptive character of chromosomal polymorphisms, the mechanisms responsible for their maintenance in natural populations is not fully understood. For this type of analysis, Drosophila subobscura is a good model species as it has a rich and extensively studied chromosomal inversion polymorphism system. Here, we examine the patterns of DNA variation in two natural populations segregating for chromosomal arrangements that differentially affect the surveyed genomic region; in particular, we analyse both nucleotide substitutions and insertion/deletion variations in the genomic region encompassing the odorant-binding protein genes Obp83a and Obp83b ( Obp83 region). We show that the two main gene arrangements are genetically differentiated, but are consistent with a monophyletic origin of inversions. Nevertheless, these arrangements interchange some genetic information, likely by gene conversion. We also find that the frequency spectrum-based tests indicate that the pattern of nucleotide variation is not at equilibrium; this feature probably reflects the rapid increase in the frequency of the new gene arrangement promoted by positive selection (that is an adaptive change). Furthermore, a comparative analysis of polymorphism and divergence patterns reveals a relaxation of the functional constraints at the Obp83b gene, which might be associated with particular ecological or demographic features of the Canary island endemic species D. guanche

Chemoreception is a crucial biological process that is essential for the survival of animals. In insects, olfaction allows the organism to recognise volatile cues that allow the detection of food, predators and mates, whereas the sense of taste commonly allows the discrimination of soluble stimulants that elicit feeding behaviours and can also initiate innate sexual and reproductive responses. The most important proteins involved in the recognition of chemical cues comprise moderately sized multigene families. These families include odorant-binding proteins (OBPs) and chemosensory proteins (CSPs), which are involved in peripheral olfactory processing, and the chemoreceptor superfamily formed by the olfactory receptor (OR) and gustatory receptor (GR) families. Here, we review some recent evolutionary genomic studies of chemosensory gene families using the data from fully sequenced insect genomes, especially from the 12 newly available Drosophila genomes. Overall, the results clearly support the birth-and-death model as the major mechanism of evolution in these gene families. Namely, new members arise by tandem gene duplication, progressively diverge in sequence and function, and can eventually be lost from the genome by a deletion or pseudogenisation event. Adaptive changes fostered by environmental shifts are also observed in the evolution of chemosensory families in insects and likely involve reproductive, ecological or behavioural traits. Consequently, the current size of these gene families is mainly a result of random gene gain and loss events. This dynamic process may represent a major source of genetic variation, providing opportunities for FUTURE specific adaptations.

Nucleotide variation at the genomic region encompassing the odorant-binding protein genes OS-E and OS-F (OS region) was surveyed in two populations of Drosophila simulans, one from Europe and the other from Africa. We found that the European population shows an atypical and large haplotype structure, which extends throughout the ∼5-kb surveyed genomic region. This structure is depicted by two major haplotype groups segregating at intermediate frequency in the sample, one haplogroup with nearly no variation, and the other at levels more typical for this species. This pattern of variation was incompatible with neutral predictions for a population at a stationary equilibrium. Nevertheless, neutrality tests contrasting polymorphism and divergence data fail to detect any departure from the standard neutral model in this species, whereas they confirm the non-neutral behavior previously observed at the OS-E gene in D. melanogaster. Although positive Darwinian selection may have been responsible for the observed unusual nucleotide variation structure, coalescent simulation results do not allow rejecting the hypothesis that the pattern was generated by a recent bottleneck in the history of European populations of D. simulans.

We present version 6 of the DNA Sequence Polymorphism (DnaSP) software, a new version of the popular tool for performing exhaustive population genetic analyses on multiple sequence alignments. This major upgrade incorporates novel functionalities to analyze large data sets, such as those generated by high-throughput sequencing technologies. Among other features, DnaSP 6 implements: 1) modules for reading and analyzing data from genomic partitioning methods, such as RADseq or hybrid enrichment approaches, 2) faster methods scalable for high-throughput sequencing data, and 3) summary statistics for the analysis of multi-locus population genetics data. Furthermore, DnaSP 6 includes novel modules to perform single- and multi-locus coalescent simulations under a wide range of demographic scenarios. The DnaSP 6 program, with extensive documentation, is freely available at http://www.ub.edu/dnasp.

The avocado, Persea americana, is a fruit crop of immense importance to Mexican agriculture with an increasing demand worldwide. Avocado lies in the anciently diverged magnoliid clade of angiosperms, which has a controversial phylogenetic position relative to eudicots and monocots. We sequenced the nuclear genomes of the Mexican avocado race, P. americana var. drymifolia, and the most commercially popular hybrid cultivar, Hass, and anchored the latter to chromosomes using a genetic map. Resequencing of Guatemalan and West Indian varieties revealed that ∼39% of the Hass genome represents Guatemalan source regions introgressed into a Mexican race background. Some introgressed blocks are extremely large, consistent with the recent origin of the cultivar. The avocado lineage experienced 2 lineage-specific polyploidy events during its evolutionary history. Although gene-tree/species-tree phylogenomic results are inconclusive, syntenic ortholog distances to other species place avocado as sister to the enormous monocot and eudicot lineages combined. Duplicate genes descending from polyploidy augmented the transcription factor diversity of avocado, while tandem duplicates enhanced the secondary metabolism of the species. Phenylpropanoid biosynthesis, known to be elicited by Colletotrichum (anthracnose) pathogen infection in avocado, is one enriched function among tandems. Furthermore, transcriptome data show that tandem duplicates are significantly up- and down-regulated in response to anthracnose infection, whereas polyploid duplicates are not, supporting the general view that collections of tandem duplicates contribute evolutionarily recent “tuning knobs” in the genome adaptive landscapes of given species.

While most patients with degenerative rotator cuff tears respond to conservative treatment, a minority progress to surgery. To anticipate these cases under class imbalance, we propose a sensitivity-constrained evolutionary feature selection framework prioritizing surgical-class recall, benchmarked against traditional methods. Two variants are proposed: (i) a single-objective search maximizing balanced accuracy and (ii) a multi-objective search also minimizing the number of selected features. Both enforce a minimum-sensitivity constraint on the minority class to limit false negatives. The dataset includes 347 patients (66 surgical, 19%) described by 28 clinical, imaging, symptom, and functional variables. We compare against 62 widely adopted pipelines, including oversampling, undersampling, hybrid resampling, cost-sensitive classifiers, and imbalance-aware ensembles. The main metric is balanced accuracy, with surgical-class F1-score as secondary. Pairwise Wilcoxon tests with a win–loss ranking assessed statistical significance. Evolutionary models rank among the top; the multi-objective variant with a Balanced Bagging Classifier performs best, achieving a mean balanced accuracy of 0.741. Selected subsets recurrently include age, tear location/severity, comorbidities, and pain/functional scores, matching clinical expectations. The constraint preserved minority-class recall without discarding or synthesizing data. Sensitivity-constrained evolutionary feature selection thus offers a data-preserving, interpretable solution for pre-surgical decision support, improving balanced performance and supporting safer triage decisions.

Chemosensory perception is a fundamental biological process of particular relevance in basic and applied arthropod research. However, apart from insects, there is little knowledge of specific molecules involved in this system, which is restricted to a few taxa with uneven phylogenetic sampling across lineages. From an evolutionary perspective, onychophorans (velvet worms) and tardigrades (water bears) are of special interest since they represent the closest living relatives of arthropods, altogether comprising the Panarthropoda. To get insights into the evolutionary origin and diversification of the chemosensory gene repertoire in panarthropods, we sequenced the antenna- and head-specific transcriptomes of the velvet worm Euperipatoides rowelli and analyzed members of all major chemosensory families in representative genomes of onychophorans, tardigrades, and arthropods. Our results suggest that the NPC2 gene family was the only family encoding soluble proteins in the panarthropod ancestor and that onychophorans might have lost many arthropod-like chemoreceptors, including the highly conserved IR25a receptor of protostomes. On the other hand, the eutardigrade genomes lack genes encoding the DEG-ENaC and CD36-sensory neuron membrane proteins, the chemosensory members of which have been retained in arthropods; these losses might be related to lineage-specific adaptive strategies of tardigrades to survive extreme environmental conditions. Although the results of this study need to be further substantiated by an increased taxon sampling, our findings shed light on the diversification of chemosensory gene families in Panarthropoda and contribute to a better understanding of the evolution of animal chemical senses.

Genetic variation is the fuel of evolution, with standing genetic variation especially important for short-term evolution and local adaptation. To date, studies of spatiotemporal patterns of genetic variation in natural populations have been challenging, as comprehensive sampling is logistically difficult, and sequencing of entire populations costly. Here, we address these issues using a collaborative approach, sequencing 48 pooled population samples from 32 locations, and perform the first continent-wide genomic analysis of genetic variation in European Drosophila melanogaster. Our analyses uncover longitudinal population structure, provide evidence for continent-wide selective sweeps, identify candidate genes for local climate adaptation, and document clines in chromosomal inversion and transposable element frequencies. We also characterize variation among populations in the composition of the fly microbiome, and identify five new DNA viruses in our samples.

Friction blisters are common among outdoor enthusiasts, yet their causes remain uncertain. This study aimed to compare foot hydration in long‐distance hikers with and without blisters, and to assess variability based on age and sex. An observational case–control study involving 86 hikers was conducted. Skin hydration was measured using a corneometer on various foot zones. Data on blister count, footwear, sex, age, and temperature were recorded. The most hydrated zones were the digital area, forefoot, and heel. Higher hydration was found in the blister group (61.6%) compared to the control group (38.4%). A significant relationship between hydration and blisters was observed in the left foot (p = 0.032). Total foot hydration was higher in women (p = 0.007) and inversely related to age (r = −0.333; p = 0.002). Hydration values above 30.40 a.u. in the right foot and 27.37 a.u. in the left foot were linked to blisters with 80% sensitivity. This study highlights the variability in foot hydration and its relationship with blisters. The influence of age and wet socks underscores the complexity of blister formation, emphasizing the need for future research on effective prevention.