Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “speciation dynamics”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2025

Latent preference for red ornamentation drives interspecific mating in nascent jumping spider species (Habronattus americanus group, F. Salticidae).

Heterospecific interactions between nascent species offer insights into how sexual selection shapes novel traits, illuminating patterns in species interactions and diversification. We tested female preferences between two recently diverged, allopatric species of jumping spiders: Habronattus americanus PLC, with red-coloured males performing short multimodal displays, and Habronattus sansoni CC, with brown-coloured males performing long multimodal displays. Mate choice experiments showed that females of both species preferred H. americanus PLC males. To examine the role of red coloration, we manipulated male coloration in both species. Results indicated that red-painted H. sansoni CC males experienced an increase in mating success, whereas brown-painted H. americanus PLCmales did not show reduced success. Our study suggests that (i) strong latent female preferences can drive unidirectional introgression across species boundaries, potentially leading to genomic homogenization; (ii) latent preferences may override preferences for existing traits; and (iii) the geographical distribution of colour morphs is consistent with a hypothesis of strong latent preferences across populations. Overall, our study demonstrates the role that mating interactions can play in speciation dynamics.

Animals↗
PubMed2025

Aplf/Dna2 variants drive chromosomal fission and accelerate speciation in zokors.

Chromosomal fissions and fusions are common, yet the molecular mechanisms and implications in speciation remain poorly understood. Here, we confirm a fission event in one zokor species through multiple-omics and functional analyses. We traced this event to a mutation in a splicing enhancer of the DNA repair gene Aplf in the fission-bearing species, which caused exon skipping and produced a truncated protein that disrupted DNA repair. An intronic deletion in Dna2, known to facilitate neo-telomere formation when knocked out, reduced gene activity. These variants collectively drove chromosomal fission in this zokor species. The newly formed chromosome became fixed due to carrying essential genes and strong selective pressure. While geographic isolation likely initiated the divergence of this species and the sister one, the fission event and associated decline at the chromosome level in gene flow probably exacerbated the speciation process. Our work elucidates the genetic basis of chromosomal fission and underscores its role in speciation dynamics.

Multiomics↗
PubMed1992

M.V. Volkenstein, evolutionary thinking and the structure of fitness landscapes.

High dimensional fitness landscapes are robustly dominated by saddle points, not isolated peaks. We present an argument to this effect that is reminiscent of May's complexity stability analysis and trace out the significance for the dynamics of speciation, the connection between the neutral and punctuated aspects of evolution and evolution on moving landscapes. The paper is written in honor of M.V. Volkenstein (October 23rd, 1912-February 18th, 1992), who devoted his last papers to uniting dynamics with evolutionary thinking.

Biological Evolution↗
PubMed2025

Molecular signatures of adaptive introgression and selection in contact zones of closely related pine species (Pinus genus).

BACKGROUND: Natural hybridization plays a key role in shaping genetic diversity, local adaptation, and the dynamics of speciation through interspecific gene flow. Hybrid zones serve as valuable natural systems for studying these processes. In this research, we used genotypic data at thousands of nuclear SNPs to investigate genomic outcomes of hybridization and selection across three contact zones of closely related pine species including Scots pine (Pinus sylvestris L.) and dwarf mountain pine (P. mugo T.). Reference allopatric stands of parental species were used to assess introgression dynamics. RESULTS: Individuals from the hybrid zones showed distinct genetic ancestry patterns and were assigned to groups including putative pure species, first-generation hybrids, and advanced backcrosses. Genotypes of the majority of hybrids were shifted towards P. mugo ancestry. Most outlier loci were shared across all sympatric populations, although some were specific to individual contact zones. The identified outliers were mainly associated with regulatory biological processes related to phosphorylation, proteolysis, and transmembrane transport. Signatures of local adaptation varied in different genetic classes in contact zones and they were strongest in pure P. sylvestris and hybrids with a majority of P. sylvestris ancestry. The pattern suggests that it may be driven by adaptation to peat bog habitats situated outside the species’ core ecological niche. CONCLUSIONS: Our findings indicate strong selective pressure acting on multiple genes in groups of hybrids and pure Pinus sylvestris individuals across all studied hybrid zones. In contrast, the weaker signal of selection observed in individuals with P. mugo ancestry suggests that relict populations of this species, which historically spread across postglacial peat bogs, were pre-adapted to such environments. While several outlier loci were shared across different contact zones, others were unique for one of them, indicating that local environmental pressures and adaptive introgression shape the genomic composition of the populations. These results highlight the role of hybridization in generating adaptive diversity and emphasize the evolutionary significance of hybrid zones in pines.

Hybridization, Genetic↗
PubMed1992

Applications of nuclear analytical techniques in environmental research. Plenary lecture.

Among nuclear analytical techniques, neutron activation analysis (NAA) is particularly useful for environmental studies. It affords low detection limits for many elements, high specificity and few sources of systematic error, which means that high accuracy is attainable. Neutron activation analysis is particularly useful for trace and ultra-trace analysis of environmental samples (water, soils, rocks and biological material). In trace element work associated with pollution, instrumental NAA is a powerful technique for multi-element surveys, in particular when combined with other spectroscopic techniques. Nuclear techniques, as with most analytical techniques, cannot be used to distinguish between different physico-chemical forms of an element per se. When used in combination with appropriate separation techniques, however, nuclear techniques can provide valuable information about trace element speciation in environmental and biological systems. From dynamic tracer experiments, i.e., addition of chemically well defined labelled compounds to environmental systems, valuable information can be obtained on the distribution of species and on microchemical processes influencing the physico-chemical forms. In these laboratories, speciation studies on trace elements in natural waters have been carried out by using instrumental NAA in combination with physical separation techniques, such as dialysis and ultrafiltration, in situ and in the laboratory. Dynamic radiotracer experiments have provided important information about processes influencing the speciation of trace elements in aquatic systems. Sequential extraction techniques have proved to be useful in studies on sediments and soils when combined with NAA. Sequential extractions also provide significant information about the physico-chemical behaviour of radionuclides supplied to natural soils from the Chernobyl accident.

Environmental Pollution↗
PubMed2025

The effects of cryptic diversity on diversification dynamics analyses in Crocodylia.

Incomplete taxon sampling due to underestimation of present-day biodiversity biases diversification analysis by favouring slowdowns in speciation rates towards the recent time. For instance, in diversification dynamics studies in Crocodylia, long-term low net-diversification rates and slowdowns in speciation rates have been suggested to characterize crocodylian evolution. However, crocodylian cryptic diversity has never been considered. Here, we explore the effects of incorporating cryptic diversity into a diversification dynamics analysis of extant crocodylians. We inferred a time-calibrated cryptic-species-level phylogeny using cytochrome b sequences of 45 lineages compared with the formally recognized 26 crocodylian species. Diversification rate estimates using the cryptic-species-level phylogeny show increasing speciation and net-diversification rates towards the present time, which contrasts with previous findings. Cryptic diversity should be considered in future macroevolutionary analyses; however, the representation of cryptic extinct taxa represents a major challenge. Additionally, further investigation of crocodylian diversification dynamics under different underlying genomic data is encouraged upon advances in population genetics. Our case study adds to the diversification dynamics knowledge of extant taxa and demonstrates that cryptic species and robust taxonomic assessment are essential to study recent biodiversity dynamics with broad implications for evolutionary biology and ecology.

Animals↗
PubMed2025

Genomic analyses of three Acanthus L. species provide insight into polyploidization-driven speciation and evolution.

Allopolyploidy fundamentally influences plant evolution, yet the genomic dynamics of allotetraploidization remain incompletely understood. We investigated Acanthus tetraploideus (2n = 4x = 96), an ecologically significant allotetraploid true mangrove from Indo-West Pacific intertidal zones. Our prior integrative investigations indicate that A. tetraploideus originated through hybridization of the diploid species A. ilicifolius and A. ebracteatus with subsequent chromosome doubling. Here, we present complete chromosome-scale genome assemblies for all three species, representing the first genomic resources for true mangrove polyploid research. Our analysis reveals that the three species have experienced at least four rounds of polyploidization events, with the most recent, approximately 53 mya, possibly an Acanthus-specific event. The allotetraploid A. tetraploideus, which emerged between 1.5 and 2.2 mya, has A. ebracteatus as its maternal progenitor and A. ilicifolius as its paternal one. Through a comprehensive genomic comparison and analysis of homoeologous gene expression, we propose a gradual evolutionary trajectory for allotetraploidy in A. tetraploideus. Despite the allotetraploidization event dating back to around 2 mya, A. tetraploideus retains a high degree of colinearity with its ancestral genomes, with the majority (76.2%) of duplicated genes retained and no significant sub-genome bias in gene expression. Furthermore, we have identified positive selection in specific genes that may facilitate the adaptation of Acanthus mangrove species to their intertidal habitats. These findings establish A. tetraploideus as a model for studying allopolyploid evolution while providing new insights into mangrove speciation processes.

Genome, Plant↗
PubMed1989

Saltatory transitions are a naturally occurring property of evolving systems.

On the basis of paleological evidence, it has been suggested that biological evolution need not necessarily be characterized by gradual change. Rather, evolutionary history may display saltatory periods of rapid speciation alternating with periods of relative quiescence, the whole dynamic being called punctuated equilibria. The empirical evidence that has been presented in support of this hypothesis has been the object of a vigorous dispute. Mathematical investigations of complex models of biological evolution that contain random elements have demonstrated that these systems can display saltatory behavior. In this paper we address a more abstract question: can saltations occur in the evolution of very simple, deterministic mathematical systems that function in a constant environment? The answer appears to be yes. Saltations appear as a natural dynamical behavior in the evolution of simplistic information processing networks. We stress that these networks do not constitute a model of biological evolution. However, the appearance of saltations in such simple systems suggests that their appearance in a process as complex as biological evolution is not surprising.

Animals↗
PubMed1977

Questions concerning environmental mobility of arsenic: needs for a chemical data base and means for speciation of trace organoarsenicals.

Biomethylation of metals, including arsenic, apparently occurs as a global process. Health control strategies therefore depend on accurate analysis of arsenic's environmental mobility. Determining to what extent biotransformations occur and how resultant organometal(loids) are sequestered in food chains requires sophistication beyond present-day total element determinations. Rather, active molecular forms of arsenic must be speciated for each environmental compartment, and it is necessary to quantify the dynamics of arsenic's mobility. Thus, new chemical facts are needed yielding rates of methylation or demethylation of arsenic; partition coefficients of organoarsenicals between air, water, and organic phases; and arsenic redox chemistry in polar media. NBS research in this context is reviewed with examples of recent results emphasizing speciation methodology. Topic areas discussed are: the nature of aquated methylarsenic species (NMR and laser-Raman spectroscopy); transport of methylarsenicals from aqueous media (gas chromatography-graphic furnace AA detection applied to metabolic Me3As formation); and speciation of involatile organoarsenicals in aqueous media (demonstration of HPLC utilizing element-specific AA detection and appraisal of electrochemical detectors).

Air↗
PubMed2025

Integrating hotspot dynamics and centers of diversity: a review of Indo-Australian Archipelago biogeographic evolution and conservation.

The Indo-Australian Archipelago (IAA) is the world's preeminent marine biodiversity hotspot, distinguished by its exceptional species richness in tropical shallow waters. This biodiversity has spurred extensive research into its evolutionary and biogeographic origins. Two prominent theoretical frameworks dominate explanations for the IAA's biodiversity: the "centers-of hypotheses" and the "hopping hotspot hypothesis". The "centers-of hypotheses" posits that specific regions serve as key sources of IAA biodiversity, either through the accumulation and overlap of species from external areas or via elevated rates of local speciation. In contrast, the "hopping hotspot hypothesis" asserts that biodiversity hotspots are dynamic, shifting across geological timescales in response to tectonic and environmental changes. This review synthesizes these contrasting perspectives into an integrated framework, the "Dynamic Centers Hypothesis," which proposes that as biodiversity hotspots migrate over time, the IAA's role in generating and sustaining biodiversity has evolved, with varying contributions from different sources dominating distinct historical phases. By synthesizing the evidence for both hypotheses and incorporating recent findings, including fossil and phylogeography data, we propose the "Dynamic Centers Hypothesis" as a comprehensive and unifying explanation for the IAA's biodiversity. The review further explores biogeographic delineation, aligning tropical marine realms with the IAA's evolutionary trajectory, from its Tethyan roots to its modern Indo-West Pacific dominance. Looking forward, advances in DNA barcoding and genomics are uncovering vast cryptic diversity, revolutionizing our comprehension of IAA phylogeographic history. These discoveries underscore the imperative for a multidimensional conservation framework, integrating phylogenetic, and functional diversity, to preserve this biodiversity hotspot amid escalating global change.

Biogeography↗
PubMed2024

Extreme elevational migration spurred cryptic speciation in giant hummingbirds.

The ecoevolutionary drivers of species niche expansion or contraction are critical for biodiversity but challenging to infer. Niche expansion may be promoted by local adaptation or constrained by physiological performance trade-offs. For birds, evolutionary shifts in migratory behavior permit the broadening of the climatic niche by expansion into varied, seasonal environments. Broader niches can be short-lived if diversifying selection and geography promote speciation and niche subdivision across climatic gradients. To illuminate niche breadth dynamics, we can ask how "outlier" species defy constraints. Of the 363 hummingbird species, the giant hummingbird (Patagona gigas) has the broadest climatic niche by a large margin. To test the roles of migratory behavior, performance trade-offs, and genetic structure in maintaining its exceptional niche breadth, we studied its movements, respiratory traits, and population genomics. Satellite and light-level geolocator tracks revealed an >8,300-km loop migration over the Central Andean Plateau. This migration included a 3-wk, ~4,100-m ascent punctuated by upward bursts and pauses, resembling the acclimatization routines of human mountain climbers, and accompanied by surging blood-hemoglobin concentrations. Extreme migration was accompanied by deep genomic divergence from high-elevation resident populations, with decisive postzygotic barriers to gene flow. The two forms occur side-by-side but differ almost imperceptibly in size, plumage, and respiratory traits. The high-elevation resident taxon is the world's largest hummingbird, a previously undiscovered species that we describe and name here. The giant hummingbirds demonstrate evolutionary limits on niche breadth: when the ancestral niche expanded due to evolution (or loss) of an extreme migratory behavior, speciation followed.

Animals↗
PubMed2025

Quaternary Glaciation Accelerates Speciation in Aquatic Snakes Through Recent Bottlenecks.

Climatic fluctuations during glacial periods have profoundly shaped the demographic history and gene flow dynamics of many taxa. This study integrated high-throughput sequencing of 67 individuals with comprehensive genomic analyses to investigate biogeographic patterns, genetic divergence and demographic trajectories in the Opisthotropis latouchii species complex, a group of mountain stream snakes distributed across Central China. Our analyses revealed substantial genetic divergence, identifying four distinct lineages, each confined to one of the four major mountain ranges in Central China, including one previously unrecognised species. These lineages exhibited distinct demographic signatures, with population bottlenecks occurring during Quaternary glaciations. Initial isolation in the glacial refugia of the southern regions of these mountains during the Late Pliocene was followed by postglacial expansions along a northward trajectory, with further divergence along a latitudinal gradient associated with mountain distribution. Notably, the mountain ranges of Central China acted as critical refugia during glacial periods, promoting rapid speciation, and as dispersal corridors during interglacial periods, facilitating range expansion and enabling recent gene flow. These findings highlight the profound impact of Quaternary climatic oscillations on genetic structure, demographic history and gene flow patterns of these endemic taxa.

Animals↗
PubMed2025

Mapping Species Birth Across the Recombination Landscapes of Marine Snails.

Understanding the drivers of heterogeneous genomic divergence is essential for uncovering the mechanisms that generate and constrain biodiversity. The extent to which adaptation and speciation are facilitated by reorganisation of the recombination landscape remains untested in many systems. Marine ecosystems, with their dynamic and fluid habitats, offer a compelling context to investigate genomic divergence. In this study, we mapped genomic divergence and selection across recombination landscapes of parapatric marine snail sister species that we show have recently undergone secondary contact. Regions of reduced recombination were enriched for genes exhibiting signatures of negative selection, whereas regions of high recombination were associated with genes under putative positive selection. Notably, the recombination landscape of the population in parapatry of one species (Scurria viridula) differs markedly from that of the other population within this same species, highlighting the role of introgression in reshaping recombination landscapes. In the other species (Scurria zebrina), conservation of the recombination landscape and divergent selection among populations suggest trapping of beneficial allele combinations in regions of low recombination maintains the identity of this species. Among species, signals of divergence with gene flow consistently cluster within specific genomic regions characterised by high recombination rate variation among the populations of S. viridula. These results challenge traditional theoretical expectations of recombination evolution by showing that the causes of genomic divergence can be population-specific. This study demonstrates that recombination landscapes are key modulators of genomic divergence, with contemporary evolutionary shifts that could enable populations to adapt to distinct environments. Our findings provide new insights into the interplay between recombination, selection, and gene flow during speciation, underscoring the complexity of evolutionary trajectories in marine systems.

Genetic Introgression↗
PubMedDate not supplied

[Progress of ecological parasitology--parasite communities].

Many of the major development in the field of parasite community ecology have been due to a switch in focus from a search for pattern to investigation of the processes that produce those patterns. This switch has been accompanied by a recognition that different processes operate at the scale of the individual host (processes determining host specificity and attributes of the niches of the parasites), within the unit of habitat (processes determining population dynamics, exchange of parasites, and transmission), and among units of habitat (processes determining colonization, extinction, or local speciation of parasites). Further developments are likely to depend upon the coordinated use of models, experimental approaches, and field observations aimed at clarifying the conditions under which the processes at each scale became particularly important.

Animals↗
PubMed2026

Recurrent hybridization shapes the diversification of Western Palearctic common toads (Bufo bufo complex).

Glacial cycles repeatedly fragmented temperate species into refugial populations, fostering divergence as a first stage towards speciation. Yet, interglacial expansions often reconnected these lineages, allowing gene flow to erode differentiation and reshape phylogeographic trajectories. We investigate these dynamics in Western Palearctic common toads (Bufo bufo complex), integrating genome-wide ddRAD-seq loci with an extensive mitochondrial dataset. Phylogenomic analyses resolved the three recognized species B. eichwaldi, B. spinosus and B. bufo, and within the latter, four major lineages distributed across the Apennine Peninsula, the Balkans, the Caucasus, and northern Europe. Mitochondrial and nuclear patterns were deeply discordant, and different approaches of historical gene flow inferences all supported past hybridization. In particular, our analyses suggest that the Caucasian population, previously attributed to the disputed species "B. verrucosissimus" based on its deeply divergent mtDNA, represents a shallow nuclear lineage within B. bufo and forms a broad intergradation zone with the Balkan lineage in Anatolia, arguing against a species status. Altogether, these results highlight a recurrent process in which refugial lineages do not diverge in strict isolation but repeatedly experience gene flow, thus reducing opportunities to speciate, and blurring tree-based phylogeographic and systematic hypotheses.

Amphibia↗
PubMed1990

The interplay of population dynamics and the evolutionary process.

Long-term maintenance of genetic diversity is affected by ecological forces that are driven in turn by current levels of genetic variation. The strength of population regulation and the consequent patterns of population fluctuations determine the likelihood of genetic changes considered pivotal for rapid speciation. However, genetic diversity in the susceptibility to regulatory forces can reduce the magnitude of such fluctuations and minimize the likelihood of genetic revolutions. A group of populations that experiences local extinctions and recolonizations may hold lower levels of genetic diversity than in the absence of such extinctions, but local adaption, which provides enhanced genetic diversity, can reduce the likelihood of local extinctions. Tightly regulated populations experience different selection pressures than poorly regulated populations, although tighter regulation itself can evolve. When genotypic variation affects the outcome of interspecific interactions on a local scale, this effect, coupled with appropriate spatial variation, can enhance the resilience of the interactive system.

Animals↗
PubMed2025

Chromosome-Level Genome Assembly of Eden's Whale Clarifies the Taxonomy and Speciation of Bryde's Whale Complex.

Eden's whale (Balaenoptera edeni), a poorly understood baleen cetacean, has long been shrouded in taxonomic ambiguity due to limited genomic resources, obscuring its distinction from closely related species and its position within the cetacean Tree of Life. In this paper, we present a high-quality chromosomal-level genome of B. edeni and conduct comparative genomic analyses to address long-standing taxonomic confusion and elucidate speciation of balaenopterids. Our phylogenomic analysis and demographic reconstruction reveal that B. edeni is a distinct sister to Bryde's whale (Balaenoptera brydei), sharing a common ancestor that diverged approximately 7.84 million years ago during the late Miocene. Their genetic divergence exceeds typical intraspecific variation in whales, supporting the reinstatement of B. brydei as a valid species. Chromosomal syntenic analyses suggest that macro-fragment inversions contributed to speciation in balaenopterid whales and uncover unexpected large-scale complex genome rearrangements in Bryde's whale, offering novel insights into cetacean genome evolution. Functional enrichment analysis of inverted regions between B. edeni and Balaenoptera musculus indicates their predominant association with metabolism and biosynthesis, as well as responses to various substances, stress, and stimuli. These genomic resources for B. edeni not only lay a critical foundation for comparative genetic and evolutionary research of cetaceans but also advance our understanding of the taxonomy and evolutionary dynamics of the Bryde's whale complex, with broader implications for baleen whale conservation and biodiversity.

Animals↗
PubMed1987

The frequency of shifts between alternative equilibria.

We derive a formula giving the frequency with which random drift shifts a population between alternative equilibria. This formula is valid when such shifts are rare (Ns much greater than 1), and applies over a wide range of mutation rates. When the number of mutations entering the population is low (4 N mu much less than 1), the rate of stochastic shifts reduces to the product of the mutation rate and the probability of fixation of a single mutation. However, when many mutations enter the population in each generation (4 N mu much greater than 1), the rate is higher than would be expected if mutations were established independently, and converges to that given by a gaussian approximation. We apply recent results on bistable systems to extend this formula to the general multidimensional case. This gives an explicit expression for the frequency of stochastic shifts, which depends only on the equilibrium probability distribution near the saddle point separating the alternative stable states. The plausibility of theories of speciation through random drift are discussed in the light of these results.

Adaptation, Biological↗