Molecular Ecology最新文献

During Pleistocene cold stages, European temperate forests were not only restricted to refugia in the southern European peninsulas. Rather, there is increasing evidence for the survival of trees also in isolated patches further north, termed ‘northern refugia’. While their existence is undisputed, based on what is known from a handful of tree species, there is very limited knowledge about forest understoreys. Here, we fill this gap by examining the evolutionary histories of three Central European forest understorey species (FUS; Aposeris foetida, Cardamine trifolia, Hacquetia epipactis). To do so, we use a set of exploratory and explicit analyses utilising genomic data and ecological niche models, and interpret these data following a priori defined framework. We identify the northwestern Balkan Peninsula as the primary diversification center for the three species but found additional northern refugia in the Alps, the Carpathians, and the Apennines. Divergence times indicated pre-Last Glacial Maximum (LGM) diversification within each FUS, suggesting persistence of forest islands in Central Europe during Pleistocene cold stages rather than exclusively post-LGM colonisation. We conclude that FUS thrived in scattered northern refugia. This refines our understanding of past forest dynamics and further supports widespread long-term persistence of forest patches in Central Europe during Pleistocene cold stages.

Biological invasions are major drivers of recent biodiversity changes, yet the genetic structure and ecological mechanisms underlying invasion dynamics remain poorly resolved in invasive social insects. In South Africa, the European wasp Vespula germanica (Hymenoptera: Vespidae), introduced in the 1970s, has spread remarkably more slowly than in other regions and its geographical distribution in the country remains limited. Although two mitochondrial haplotypes have been reported in South Africa, the species' range expansion and fine-scale population structure remain poorly understood. Using 2b-RAD sequencing of 47 colonies across its entire range in South Africa, we identified two main genetic clusters that correspond to previously identified mitochondrial haplotypes, strongly supporting the double introduction scenario. This well-defined genetic structure is sustained by limited gene flow and possibly by niche preferences. Spatial patterns reveal a dispersal system of short-range natural movements and human-mediated jumps, with Stellenbosch acting as a secondary introduction point. Ecological niche preferences appear to maintain a genetic structure through isolation by environment: one group occupies warmer, drier sites, while the other is confined to cooler, wetter microclimates near Cape Town. This pattern reflects ecological adaptation that is likely tied to distinct population origins. As the first genome-wide study of V. germanica, this work illuminates how introduction history and ecological constraints shape invasion dynamics, laying a foundation for understanding the genetic structure and invasion dynamics of the species and for developing predictive management frameworks.

Colour polytypism represents an example of phenotypic diversification shaped by genetic divergence and ecological pressures. Poison frogs of the genus Oophaga (Dendrobatidae) are highly polytypic in coloration, making them an ideal system for investigating the genetic and physiological basis of colour variation. We examined gene expression, pigment and histological differences across four colour morphs (aquamarine, brown, green, and red) of Oophaga vicentei from mainland Panama. RNA sequencing revealed 1838 and 5085 differentially expressed genes (DEGs) in the skin and liver, respectively. Melanin synthesis genes were upregulated in the brown morph, whereas pteridine pathway genes were upregulated in red and green morphs, consistent with previous findings in O. pumilio. In aquamarine frogs, pigment composition was similar to brown and green frogs, but transcriptional profiles were highly divergent. Red morphs upregulate a paralog of the dendrobatid ketolase cyp3a80 in the liver, suggesting modified ketolation mechanisms in O. vicentei. This is consistent with higher ketocarotenoid accumulation in red frogs. Co-expression network analysis identified morph-related modules in both tissues but the relationship between modules and known pigmentation pathways remains unclear. Comparative analysis across seven dendrobatid species revealed conserved pigmentation genes (e.g., xdh, ttc3b) alongside morph-specific expression patterns. Our results show that red frogs are dissimilar in pigments, chromatophore structure, and gene expression, whereas aquamarine, brown, and green coloration share overlapping pigment profiles and chromatophore organisation, with transcriptional differences suggesting structural or regulatory mechanisms.

Crown-of-thorns sea star (CoTS) outbreaks are a main cause of hard coral cover decline across the Indo-Pacific, posing a major threat to the resilience of coral reefs. However, the drivers underlying CoTS feeding on preferred (e.g., Acropora species) versus non-preferred (e.g., Porites species) are poorly understood. We hypothesised that coral venom may influence CoTS prey preferences. To investigate this hypothesis, we compared the coral venom toxin families across the genomes of preferred (A. digitifera, A. hyacinthus, A. millepora and A. tenuis) and non-preferred (P. australiensis, P. compressa, P. lutea and P. rus) prey species of CoTS. We also included one species from each genus inhabiting the Caribbean, where CoTS are absent (A. cervicornis and P. astreoides), to broaden our identification of venom constituents shared within each genus and investigate geographic differences. We collected known cnidarian toxins, and along with the cnidarian Tox-Prot database, used these to identify putative toxins and investigate their phylogeny. The most abundant toxins across all coral species included neurotoxins (kunitz-type and SCRiPS) and pore-forming toxins (actinoporins and MAC-PFs). We found genera-specific differences with jellyfish toxins (CFXs) only present in Porites species. Similarly, only Acropora species harboured pore-forming toxins with the aerolysin domain. Two toxin homologues only present in Indo-Pacific corals (CFX and MAC-PF homologues) showed evidence of positive selection, suggesting their evolution is shaped by environmental pressures, including exposure to CoTS. These findings provide a foundation for future studies of scleractinian venoms, which have direct applications to assessing reef coral's susceptibility to future CoTS outbreaks and active reef management.