Evolutionary Applications最新文献

Drought has been identified as one of the important environmental factors in the context of climate change due to its interaction with other biotic and abiotic stresses. However, only a few studies have reported the effect of breeding on forest adaptability to climate change. Using a common garden experiment with seedlings from families of Scots pine (Pinus sylvestris L.) from northern Sweden, we have found differences in drought tolerance between seedlings from breeding stands and those from natural forests. We performed a genetic analysis including high-throughput image-based phenotyping of seedling canopy and root traits and conducted metabolomic and hormone analyses with the aerial parts of the seedlings. Our results indicate that root architecture traits associated with drought tolerance exhibit moderate to high heritability. Analyses of seedling architecture reveal that families from breeding stands have higher drought resistance but lower genetic variation than the ones from natural forests, especially in the case of canopy traits. Metabolomic and hormone analyses of the aerial parts of the seedlings also support that the breeding stands may have a higher capacity to withstand or deal with drought conditions as compared to the natural forests. For example, increase in abscisic acid along with increase in tryptophan and auxin conjugates in the breeding stands compared to the natural forests under drought conditions may contribute to alleviation of drought response in the breeding stands. The methodology employed to evaluate drought tolerance and plant architecture in this study might be useful for future research and forest management focused on climate change adaptability.

Pest management programmes can operate more effectively when movement patterns of target species are known. As individual insects are difficult to track, genomic data can instead be used to infer movement patterns based on pest population structure and connectivity. These data can also provide critical information about cryptic taxa relevant to management. Here we present the first genomic investigation of Aedes vigilax, the Australian saltmarsh mosquito, a major arbovirus vector across Australasia. We used a ddRAD pool-seq approach and a draft genome assembly to investigate genetic variation in 60 Ae. vigilax pools from across Australia but with a focus on urban Newcastle and Sydney, NSW. There was strong genetic structure between samples from the west and east coasts of Australia, and additional structure that differentiated east coast populations. Within Newcastle and Sydney, contrasting patterns of genetic structure were evident. In Newcastle, there was no differentiation among subregions up to 60 km apart. In Sydney, samples from one urban subregion were differentiated from others < 3 km apart, and this structure was stable across sampling years. Heterozygosity and Tajima's D indicated no bottlenecks in Newcastle or Sydney populations, suggesting this structure represents a gene flow barrier. Nuclear differentiation patterns contrast with previous mtDNA data indicating two COI clades in the east coast, one of which was also present in Western Australia. The panmixia over 60 km across the Newcastle region corroborates previous field observations of high dispersal capacity in this mosquito. These findings indicate specific challenges that may hinder local suppression strategies for this species.

There is growing evidence for the role of introgressive hybridization in promoting species adaptation (i.e., adaptive introgression) owing to increasing genomic studies on a diversity of taxa over the past decades. However, introgressive hybridization was, and still is, regarded as a homogenizing process hindering the evolutionary process of adaptation to selection pressures. Despite methodological advances, key gaps remain in understanding how adaptive introgression due to hybridization functions across taxonomic groups and biological levels. This study has three objectives: (1) to explore historical trends in the understanding of adaptive introgression, particularly its genomic and functional dimensions; (2) to investigate structural organismal characteristics influencing patterns of adaptive introgression; and (3) to evaluate how adaptive introgression interacts with counteracting evolutionary mechanisms. We carried out a systematic review of the adaptive introgression literature and a multidimensional meta-analysis. The current knowledge trends have been shaped by the genomic revolution. Since 2012, genomic studies have contributed to establishing a clearer understanding of adaptive introgression. The amount and variety of published studies increased from bacteria to mammals across a complexity gradient, focusing on the genomic level and progressively having consequences at a greater number of levels of biological organization (from physiological and demographic to behavioral/ecological). Testing for tendencies, our study also revealed evolutionary mechanisms linked to adaptive introgression co-occurring with divergence forces, demonstrating that these processes are not mutually exclusive, even when they act in opposite directions, i.e., convergence and divergence, such as autosomal introgression (versus islands of differentiation in sex-linked chromosomes), balancing selection (versus genetic drift), or sexual selection (versus assortative mating). This balance is mediated by environmental conditions as they are frequently reported in the studies, regardless of the organisms' structural complexity, shaping the path of the evolutionary process of introgressing species. Studying introgression patterns has important implications for understanding adaptation in rapidly changing environments.

The large yellow croaker is one of the most important marine aquaculture species in China, yet its intensive farming industry faces challenges from various pathogens, particularly white spot disease caused by Cryptocaryon irritans. This study aimed to address the issue of white spot disease through genetic breeding. We implemented two consecutive generations of genomic selection (GS) of large yellow croaker against Cryptocaryon irritans, resulting in three continuous generations for subsequent analyses. Challenge tests demonstrated significantly higher 96-h survival rates in the selected generations compared to corresponding controls, with increases of 18.5% and 79.7%, respectively. Survival analysis confirmed that the two selected generations exhibited significantly stronger resistance to C. irritans. By merging the genotype files across generations, a comprehensive dataset containing 1844 individuals and 28,637 SNPs was created. Genomic Estimated Breeding Values (GEBVs) showed steady increases across the three consecutive generations, while genetic structure analysis revealed progressive population differentiation resulting from the two rounds of GS. Through genome-wide selection signature scanning, we identified five positive selection regions (PSRs) distributed across four chromosomes. These regions were enriched for multiple biological pathways related to energy metabolism, immune response, and cell death, including the HIF-1 signaling pathway, NOD-like receptor signaling pathway, and apoptosis. Within these pathways, we identified key candidate genes, including crebbp in the HIF-1 signaling pathway and traf2 involved in immune regulation, both significantly associated with resistance to C. irritans. Our results validate the effectiveness of GS in selective breeding of large yellow croaker against C. irritans and demonstrate that just two consecutive generations of GS can induce substantial differentiation in genetic structure. This approach facilitates the identification of candidate genes and biological pathways associated with disease resistance.

Exploring evolutionary and physiological responses to environmental stress is crucial for assessing the effects of climate change on wild populations. Mussels, key inhabitants of the benthos with high ecological and economic value, are a particularly vulnerable species that may be pushed to their ecological limits as warming threatens their survival and population stability. Species within the Mytilus edulis complex are commonly found in temperate regions globally; in the Baltic Sea, populations are formed by M. edulis and M. trossulus hybrids with low levels of M. galloprovincialis introgression. This study investigates the mechanisms through which resilience towards global warming may be fast-tracked in Baltic mussels (Kiel, Germany). For this, we studied two cohorts of juvenile mussels (recently settled animals), one exposed to an extreme heat event early in life and one naïve to this stressor. Both cohorts were later exposed to experimental temperatures ranging from 21°C to 26°C, with animal performance measured after 25 days. Impacts of thermal stress on the genetic composition of each cohort was then assessed by genotyping 50 individuals using a blue mussel 60 K SNP-array. We observed a significant increase in M. edulis genotypes together with a decrease in M. trossulus in the challenged cohort, compared to naive juveniles. We also found exposure to high temperature affected performance of mussel cohorts, reducing dry tissue weight of selected individuals. Results from this study provide insights on how selection through thermal stress impacts performance and genetic composition of key globally distributed intertidal species, with important implications for understanding and managing mussel populations under future warming scenarios.

Understanding the biological connections between populations is essential to wildlife management and conservation. Genetic studies play a central role in characterizing these connections, but typically require stratified sampling regimes to assess the spatial extent and strength of gene flow, and the relative influences of sex and ontogeny on patterns of connectivity. Yet, this can be challenging in some study systems, particularly in large marine species such as sharks, where genetic studies often rely on opportunistic and/or sampling conducted over large spatial scales. We demonstrate the importance of stratified sampling to identify previously undetected genetic structure in tiger sharks (Galeocerdo cuvier) off eastern Australia, where panmixia has been previously reported. We performed population genomic analyses on 414 tiger sharks, representing males and females and both juvenile-subadult and adult-life stages, and 21 locations spanning approximately 3000 km of eastern Australia and the Indo-Pacific region. Similar to previous studies, we demonstrate a lack of overall genetic structure across the sampling area; however, our analysis shows evidence of spatial autocorrelation and local genetic structuring in juvenile-subadult female tiger sharks. These results point to potential influences of sex and ontogeny on patterns of population genetic structure and connectivity in Australian tiger sharks. We discuss these findings in the context of essential habitats supporting tiger shark populations and risks of overstating the strength of biological connections among shark populations in the absence of appropriate sampling regimes.

Arma chinensis, a predatory insect renowned for its prey diversity in East Asia, is effective in controlling agricultural and forestry pests. However, after introducing field populations into indoor subcultures, features of inbreeding depression have surfaced within these populations. Clarifying the molecular genetic mechanism of inbreeding depression of A. chinensis is of great significance for its population protection. In this study, phylogenomic analysis revealed that the genus Arma shared a common ancestor with Halyomorpha and Nezara in the Pentatomidae family around 63.62 million years ago. Based on whole-genome resequencing of three consecutive inbred generations of A. chinensis, we investigated the genomic features of inbreeding depression. We observed an accumulation of long runs of homozygosity and extreme variations in nucleotide diversity across generations, collectively affecting 111 genes and multiple biological processes, such as sequence-specific DNA binding, synapse organization, and transcription regulatory region binding. These genomic changes suggest that successive inbreeding may disrupt normal physiological functions, potentially impairing gene expression, neural signaling, and sensory organ development. In conclusion, our study clarifies the evolutionary position of A. chinensis, highlights the genetic consequences of inbreeding, and emphasizes the importance of preserving genetic diversity in natural populations for long-term survival and adaptability.

Some organisms appear to thrive in contaminated environments, while others are more sensitive, though the causes of this variation are unclear. The toxin coevolution hypothesis posits that an evolutionary history with natural toxins preadapts species to deal with novel toxins, while the range-size-tolerance hypothesis posits that a larger geographic range selects for broader tolerance to stressors. Butterflies are a prime system to investigate these hypotheses because they are diverse, feed on a range of larval host plants that vary in defensive compounds, and many are found in polluted environments. We ask how these hypotheses explain varying tolerance to heavy metal pollution, measured here as loads of four heavy metals along an urban gradient of metal exposure. We compared 26 butterfly species that vary in their evolutionary history with mutagenic plant defensive chemicals as well as their geographic range size. We built a dataset of plant mutagenicity synthesizing 40 years of standardized mutagenicity screening in plants, including 502 plant species of 103 families within 37 orders. We used this dataset, coupled with butterfly host records, to estimate evolutionary history with mutagens. We found that butterfly species with larger ranges tolerated significantly greater concentrations of lead, arsenic, and cadmium in their tissues. Additionally, species with a history of feeding on relatively more mutagenic host plant families tolerated greater maximum lead concentrations in their thoracic tissue. This research provides additional support for the growing observation that small-ranged species are more vulnerable to environmental change, in this case, metal pollution. In addition, an evolutionary history with mutagenic host plants may provide some additional resilience, although less than geographic range size. In addition, our dataset on comparative plant mutagenicity will facilitate future research on plant-herbivore coevolution, in fields such as chemical, community, and urban ecology.

While sexual reproduction is a general feature of animals, fissiparity and budding are relatively uncommon modes of asexual reproduction by which a fragment from a parent becomes an independent organism. Unlike unitary development, tumor cells can be included in the detached fragment destined to become offspring. Although fragmentation facilitates the vertical transmission of parental tumor cells to nascent progeny, this process requires significantly fewer cell replications than development from a zygote. The former is a risk factor for cancer, while the latter reduces oncogenic mutations during replication, indicating that two opposite effects of carcinogenesis are involved in fragmentation. If fragmentation can significantly reduce the number of cell replications for the development and a small portion of parental cancer is transmitted to the offspring during fragmentation, consecutive fragmentation across generations can gradually diminish the cancer risk of offspring, which I term fragmentational purging. On the other hand, consecutive fragmentation may aggravate the cancer risk of the progeny, a process of fragmentational accumulation. The model results imply that fragmentational purging does not necessarily guarantee the evolution of fragmentation, nor does fragmentational accumulation ensure its exclusion. Other relevant factors including juvenile susceptibility of sexual reproduction and loss of genetic diversity stemming from asexual reproduction can influence the selective advantage of fragmentation. Furthermore, owing to the common features of stemness and self-renewal, the existence of pluripotent adult stem cells required for fragmentation could be coupled with elevated cancer risk. The model results across diverse parameters and the associated mathematical analyses highlight multifaceted evolutionary trajectories toward fragmentation. Further investigation of cancer-suppression strategies that fragmentational animals employ could provide insights into regenerative medicine and cancer therapy.

Cities impose unique selection pressures on wildlife and generate clines in phenotypic traits along urban–rural gradients. Roads are a widespread feature of human-dominated landscapes and are known to cause direct wildlife mortality; however, whether they act as a selective force influencing phenotypic trait variation along urban–rural gradients remains unclear. This study tested the hypothesis that roads influence natural selection of coat color in the eastern gray squirrel (Sciurus carolinensis), a species with two distinct coat colors: a gray morph that is common in all areas and a melanic morph more prevalent in urban areas than in rural ones. Vehicular collisions are a significant cause of mortality in eastern gray squirrels, with the melanic morph more visually conspicuous on roads and more easily detected and avoided by drivers than the gray morph. Standardized road cruise surveys along an urbanization gradient in Syracuse, New York, USA, revealed that the prevalence of melanism among living squirrels in Syracuse was negatively related to distance from the city center, whereas there was no urban–rural cline in melanism among road-killed individuals, with the melanic morph underrepresented among road-killed squirrels by up to 30% along the urbanization gradient. An examination of the prevalence of each color morph on and off road surfaces in a range-wide compilation of > 100,000 photographs of S. carolinensis also indicated that the melanic morph was underrepresented among road-killed squirrels imaged. Our study highlights vehicular collisions as an important source of natural selection on phenotypic traits, suggesting a potential role in shaping patterns of urban evolution and contributing to the maintenance of urban–rural clines.