Evolution最新文献

Weiss & Berv (2025) proposed and tested a resource longevity hypothesis on marine invertebrates in deep-sea ecosystems. They found that organisms in ephemeral environments have faster substitution rates, whereas those in stable environments have slower rates. The study confirmed that evolutionary rates differ across habitat types, a pattern the authors attributed to habitat longevity. Notably, there was no significant association between species body size and evolutionary rate. This suggests that resource variability drives evolutionary rates in these extreme environments.

Allelic dominance and phenotypic plasticity both influence how genetic variation is expressed in phenotypes, shaping evolutionary responses to selection. In both cases, changes in genotype or environment can cause sharp, nonlinear phenotypic shifts, hinting at shared underlying features of development that may link dominance and plasticity. Here, we investigate these links using a Mendelian, female-limited color dimorphism found in many species of the Drosophila montium lineage. In most species, the Dark allele is dominant, but two species-D. jambulina and D. cf. bocqueti-have been reported to have dominant Light alleles. We show that in both Dark-dominant and Light-dominant species, the color dimorphism is linked to the same locus: the POU domain motif 3 (pdm3) transcription factor. We then demonstrate that the interspecific differences in dominance relationships between pdm3 alleles are due to changes in phenotypic plasticity. In the Dark-dominant species D. rufa and D. burlai, the Dark allele is dominant across all developmental temperatures. In contrast, in both Light-dominant species, dominance is temperature-dependent, with the Light allele becoming increasingly dominant at higher temperatures. These results suggest a mechanistic connection between dominance and phenotypic plasticity. We propose that this connection may emerge from threshold-like properties of developmental systems.

Phenotypic plasticity can alter evolutionary dynamics, but its genomic consequences remain contested. Barkdull & Moreau (2025) combine comparative genomics and developmental transcriptomics in Cephalotes turtle ants to show that the repeated evolution of a soldier morph produces an asymmetric genomic signature: protein-coding genes experience genome-wide relaxed selection and reduced positive selection, whereas conserved noncoding regulatory elements show increased purifying constraint. Worker morph plasticity is driven mainly by co-option of ancient genes and by integration of insulin, imaginal-disc, and Hippo signaling.

Understanding the drivers of biodiversity over time is a central goal in macroevolution. Yet, the relative contributions of biotic and abiotic mechanisms remain unclear, especially at broader phylogenetic and spatial scales. This study investigates how biotic (competition proxies) and abiotic (temperature) factors shaped Carnivora diversification across North America and Eurasia over the last 45 million years. Using a Bayesian framework, curated fossil data, and an expanded method to assess competition intensity at multiple spatial scales, we quantify speciation, extinction, and diversity patterns across 17 families. Our results show that competition significantly influences diversification on both continents. While competition can hinder speciation by saturating ecological niches, it may also foster diversity via character displacement and niche partitioning, especially under local spatial coexistence. At regional scales, abiotic factors-particularly cooling temperatures and habitat shifts-act as selective extinction drivers, disproportionately affecting specific regions of the body size traitspace and creating gaps. By integrating temporal and spatial perspectives, our study enhances understanding of how biotic interactions and environmental changes jointly shape biodiversity through deep time.

In song-learning birds, vocalizations are species recognition signals and may act as premating reproductive barriers; for allopatric taxa, testing how the signals can influence the speciation processes is quite challenging. This study aims to understand genomic divergence and species recognition via songs in 2 allopatric taxa, eastern and western Nashville warblers (Leiothlypis ruficapilla ruficapilla vs. Leiothlypis ruficapilla ridgwayi). We performed playback experiments to assess their reciprocal behavioral responses, which suggests an asymmetric barrier: the eastern L. r. ruficapilla discriminates between the 2 songs, but the western L. r. ridgwayi does not. Using whole-genome sequencing, we also examined the extent of the taxa's genomic divergence and estimated their demographic history. We identified dozens of highly differentiated genomic regions, as well as fluctuations in historical effective population sizes that indicate independent demographic trajectories during the Pleistocene. To contextualize the magnitude of divergence between L. ruficapilla subspecies, we applied the same genomic analyses to 2 additional eastern-western pairs of parulid warblers, Setophaga virens vs. Setophaga townsendi and Setophaga coronata coronata vs. Setophaga coronata auduboni, which have existing behavior studies but are not in strict allopatry. Our findings provide insights into the role of vocalizations in defining within-pair relationship and the important legacy of isolation during the Pleistocene.

Organisms adapt to environmental change by plastic phenotypic responses, genetic adaptation, or a combination of the two. Beyond adapting to the environment, organisms can also evolve the ability to adapt more effectively. Evolution can enhance their capacity to respond to environmental cues (increased plasticity), but also their capacity to harness the effects of mutations (increased evolvability). However, it is unclear how these different adaptive capacities co-evolve. Here, we present an evolutionary simulation study in which a simple gene regulatory network must adapt to various regimes of environmental change. We systematically investigate the evolution of plasticity and evolvability in this network, depending on the speed and predictability of environmental changes, and the reliability of environmental cues. We find that plasticity evolves mostly under fast and erratically changing conditions, especially if cues are reliable. In contrast, evolvability evolves under intermediate environmental variability and lower cue reliability. We zoom in on network architecture to investigate what makes these networks more adaptable, showing that different parts of the network become sensitive to mutations depending on the environmental regime. Overall, our results show that both plasticity and evolvability are readily accommodated even in a simple network, depending on the selective pressures exerted by environmental change.

Swine influenza virus (SIV) is a highly contagious respiratory pathogen that causes significant economic losses in the swine industry and poses a potential health risk to humans. This study investigated the genetic diversity and evolution of the H1N1 subtype SIV across different regions of China over the past four decades. Using 959 whole-genome sequences collected between 1977 and 2020 from public databases such as GenBank and the Global Initiative on Sharing Avian Influenza Data (GISAID), we systematically analyzed the epidemiology, phylogenetics, genotypes, and molecular characteristics of the H1N1 subtype SIV. The results revealed marked temporal and geographic heterogeneity in virus distribution, with six major lineages and 25 distinct genotypes identified. The Eurasian avian-like (EA) lineage predominated, reflecting its adaptive advantage in swine populations. Genotypic turnover was evident over time, with certain genotypes (e.g., genotype 2 and genotype 3) exhibiting molecular features associated with adaptation to human hosts, thereby elevating the risk of cross-species transmission and potential pandemics. Amino acid site analysis further identified mutations favoring human-like receptor binding, mammalian adaptation, and antigenic variation. These findings highlight the ongoing evolution of H1N1 subtype SIV in China and underscore the necessity for continuous surveillance and enhanced biosecurity measures in the swine industry to mitigate future pandemic threats.

Effects on juvenile growth have long been considered an important benefit of parental care, but they have rarely been tested empirically. Protection and feeding by parents might accelerate offspring growth by allowing offspring to allocate more resources to growth (resource-allocation hypothesis). Protected young could shift investment away from defensive adaptations toward growth (defensive reallocation), and parental feeding should increase the total amount of assimilated resources (energy intake). Alternatively, rapid growth can be costly due to damage caused by reactive oxygen species, and parental protection might facilitate slower growth to avoid this (costly acceleration hypothesis). We tested these hypotheses along with the suggestion that egg and adult size are correlated with growth in a common-garden study of 17 species of carrion beetles (Silphinae, a subfamily of the beetle family Staphylinidae). Our results were consistent with the resource-allocation hypothesis but did not support the costly acceleration hypothesis or the idea that egg or adult size constrains growth. Species that are normally protected by parents grew faster, not slower, than those that are not. This was true even when their parents were removed and could not feed, supporting the concept of defensive reallocation. As expected based on greater energy intake, the young of species with parental feeding grew faster when their parents were present than when they were not. When phylogeny was accounted for, neither egg nor adult size was related to early growth rate.

Rates of molecular, phenotypic, and lineage diversification typically scale negatively with time interval of measurement, raising longstanding questions about time-dependency of evolutionary processes. These patterns and their potential meaning have recently re-entered evolutionary discussions. In this Perspective, we revisit the general challenges in interpreting rate-time relationships. Much apparent temporal scaling of evolutionary rate is an inescapable outcome of plotting a ratio against its denominator, either directly or indirectly. Highly unlikely relationships between timescale and accumulated evolutionary change are required to produce anything other than negative rate-time relationships. Simulations reveal that constant-rate evolutionary processes readily generate negative rate-time scaling relationships under many conditions, and that a range of rate-time scaling exponents can be generated by different evolutionary processes. Reanalysis of 6 empirical datasets reveals unscaled magnitudes of evolution that are either unrelated to time and/or vary in their relationship with time. Over 99% of variation in rate-time relationships across 6 datasets is explained by time variation alone. We further evaluated a recent hypothesis that evolutionary rate-time scaling reflects three modes of change, from micro- to macroevolutionary time scales using break-point regression, but we found no strong support for this hypothesis. Taken together, negative rate-time relationships are therefore largely inevitable and challenging to interpret. In contrast, it is more straightforward to assess how evolutionary change accumulates with time.