A wide hybrid zone mediated by precipitation contributed to confused geographical structure of Scutiger boulengeri

Confused geographical structure of a population and mitonuclear discordance are shaped by a combination of rapid changes in population demographics and shifts in ecology.In this study,we generated a time-calibrated phylogeny of Scutiger boulengeri,an endemic Xizang alpine toad occurring in mountain streams on the Qinghai-Xizang(Tibet)Plateau(QTP).Based on three mitochondrial DNA(mt DNA)genes,eight clades were assigned to three deeply divergent lineages.Analysis of nuclear DNA(nu DNA)genes revealed three distinct clusters without geographic structure,indicating significantly high rates of gene flow.Coalescent theory framework analysis(approximate Bayesian computation model DIYABC and Migrate-N)suggested that divergence of the main intraspecific clusters was the result of hybridization after secondary contact in the Holocene around 0.59 million years ago(Ma).The ratio of mt DNA FST(fixation index)to nu DNA FST was 2.3,thus failing to show male-biased dispersal.Geographic cline analysis showed that a wide hybrid zone was initially established in southwestern China,without significant reproductive isolation but with strong introgression in S.boulengeri,suggesting high hybrid fitness.Furthermore,mt DNA genes exhibited isolation by distance(IBD)while nu DNA genes exhibited significant isolation by environment(IBE).Results suggested that mitonuclear discordance may have initially been caused by geographic isolation,followed by precipitation-mediated hybridization,producing a wide hybrid zone and geographic structure confusion of nu DNA genes in S.boulengeri.This study indicated that complicated historical processes may have led to specific genetic patterns,with a specific climate factor facilitating gene flow in the system.

Hybrid zone and its genetic analysis: implication for conservation

Hybrid zone is a very critical concept within the evolutionary biology, because it would offer us a better insight to understand the evolutionary role of gene flow and hybridization based on the cline model. This minireview presents an expatiation of history perspectives and research developments upon basic concepts including hybrid zones, hybridization, hybrid and its the genetic cline model. Moreover, by figuring out the existing problem around the hybrids within conservative theory and practices, it suggests that the theory of hybrid zone be introduced into conservation biology and it would be provide a broader and more open theoretical background for conservative research and practices.

Spatiotemporal dynamics in butterfly hybrid zones

Evaluating whether hybrid zones are stable or mobile can provide novelinsights for evolution and conservation biology. Butterflies exhibit high sensitivity to envi-ronmental changes and represent an important model system for the study of hybrid zoneorigins and maintenance. Here, we review the literature exploring butterfly hybrid zones,with a special focus on their spatiotemporal dynamics and the potential mechanisms thatcould lead to their movement or stability. We then compare different lines of evidenceused to investigate hybrid zone dynamics and discuss the strengths and weaknesses ofeach approach. Our goal with this review is to reveal general conditions associated withthe stability or mobility of butterfly hybrid zones by synthesizing evidence obtained us-ing different types of data sampled across multiple regions and spatial scales. Finally, wediscuss spatiotemporal dynamics in the context of a speciation/divergence continuum, therelevance of hybrid zones for conservation biology, and recommend key topics for futureinvestigation.

Variation in morphological traits in a recent hybrid zone between closely related Quercus liaotungensis and Q.mongolica(Fagaceae)

Aims Hybridization usually leads to gene introgression between related spe-cies in hybrid zones,associated with complex patterns of morpho-logical variation.Nevertheless,previous studies have tended to ignore the effects of geographic variation in hybridization rates on species taxonomy.This study aims to investigate the variation of morphologi-cal traits between two sympatric and taxonomically confused oak spe-cies,Quercus liaotungensis and Q.mongolica,and reveal the effects of hybridization rates on morphological traits and the taxonomic boundary.Methods We used seven microsatellite loci to evaluate species status and measured 15 morphological traits in 26 trees in the recent hybrid zone between Q.liaotungensis and Q.mongolica,and we char-acterized the differences between the two oak species and their hybrids for the investigated traits.Important Findingsmolecular analyses indicated that 74%of 78 sampled maternal trees were hybrids between Q.liaotungensis and Q.mongolica although the observed morphological variation suggested that they had remained distinct species.across all of the differentiated leaf and reproductive traits,the hybrids expressed patterns similar to Q.liaotungensis,which may suggest dominant expression of paren-tal characters.These results are consistent with our expectation that hybrids will be difficult to distinguish from parental species in a recent hybrid zone.

Discrimination of conspecifics from heterospecifics in a hybrid zone: Behavioral and chemical cues in ants

Species and nestmate recognition in social insects occurs mostly through cuticular hydrocarbons acting as chemical cues. These compounds generate a colony-specific odor profile depending on genetic and environmental factors. Species and nestmate recognition results in specific behavioral responses, regulating the level of aggression toward other individuals during an interaction. Although species discrimination and recognition cues have been poorly studied in the context of interspecific hybridization, such systems offer an opportunity to further investigate the influence of heritable and environmental factors on recognition. We explored the strength of discrimination in a hybrid zone between two ant species—Tetramorium immigrans and T. caespitum—by comparing cuticular hydrocarbon profiles and measuring intra- and interspecific worker aggression in both areas of sympatry and areas of allopatry among species. Species cuticular hydrocarbon profiles were well-differentiated and interspecific aggression was high, revealing highly discriminating species recognition cues. Hybrids’ cuticular hydrocarbon profiles consisted of a mixture of the parental bouquets, but also exhibited hybrid-specific patterns. Behavioral assays showed that T. immigrans is as aggressive toward hybrids as toward heterospecifics. Finally, aggression between heterospecific workers was lower when interacting individuals came from areas of sympatry among species than from areas of allopatry. Taken as a whole, these findings paint a particularly complex picture of the recognition system in T. immigrans, T. caespitum, and their hybrids, and highlight that hybrid zones afford a still underexplored opportunity for investigating recognition mechanisms and discrimination between species.

Does divergence from normal patterns of integration increase as chromosomal fusions increase in number?A test on a house mouse hybrid zone

Chromosomal evolution is widely considered an important driver of speciation because it can promote the establishment of reproductive barriers.Karyotypic reorganization is also expected to affect the mea n phe no type,as well as its developme nt and patter ns of phenotypic in tegrati on,through processes such as variation in genetic linkage between quantitative trait loci or between regulatory regions and their targets.Here we explore the relationship between chromosomal evolution and phenotypic integration by analyzing a well-known house mouse parapatric contact zone between a highly derived Robertsonian(Rb)race(2n=22)and populations with standard karyotype(2n=40).Populations with hybrid karyotypes are scattered throughout the hybrid zone connecting the two parental races.Using mandible shape data and geometric morphometries,we test the hypothesis that patter ns of in tegration progressively diverge from the"normal"integration pattern observed in the standard race as they accumulate Rb fusions.We find that the main pattern of integration observed between the posterior and anterior part of the mandible can be largely attributed to allometry.We find no support for a gradual increase in divergence from normal patterns of integration as fusions accumulate.Surprisingly,however,we find that the derived Rb race(2n=22)has a distinct allometric trajectory compared with the standard race.Our results suggest that either individual fusions disproportionately affect patterns of integration or that there are mechanisms which"purge"extreme variants in hybrids(e.g.reduced fitness of hybrid shape).

Cryptic diversity and rampant hybridization in annual gentians on the Qinghai-Tibet Plateau revealed by population genomic analysis

Understanding the evolutionary and ecological processes involved in population differentiation and speciation provides critical insights into biodiversity formation. In this study, we employed 29,865 single nucleotide polymorphisms(SNPs) and complete plastomes to examine genomic divergence and hybridization in Gentiana aristata, which is endemic to the Qinghai-Tibet Plateau(QTP) region. Genetic clustering revealed that G. aristata is characterized by geographic genetic structures with five clusters(West, East, Central, South and North). The West cluster has a specific morphological character(i.e., blue corolla) and higher values of FSTcompared to the remaining clusters, likely the result of the geological barrier formed by the Yangtze River. The West cluster diverged from the other clusters in the Early Pliocene;these remaining clusters diverged from one another in the Early Quaternary. Phylogenetic reconstructions based on SNPs and plastid data revealed substantial cyto-nuclear conflicts. Genetic clustering and D-statistics demonstrated rampant hybridization between the Central and North clusters,along the Bayankala Mountains, which form the geological barrier between the Central and North clusters. Species distribution modeling demonstrated the range of G. aristata expanded since the Last Interglacial period. Our findings provide genetic and morphological evidence of cryptic diversity in G. aristata, and identified rampant hybridization between genetic clusters along a geological barrier.These findings suggest that geological barriers and climatic fluctuations have an important role in triggering diversification as well as hybridization, indicating that cryptic diversity and hybridization are essential factors in biodiversity formation within the QTP region.

Suitable growing zone and yield potential for late-maturity type of Yongyou japonica/indica hybrid rice in the lower reaches of Yangtze River, China

Late-maturity type of Yongyou japonica/indica hybrids series （LMYS） have shown great yield potential, and are being widely planted in the lower reaches of Yangtze River, China. Knowledge about suitable growing zone and evaluation of yield advantage is of practicall importance for LMYS in this region. Fifteen LMYS, two high-yielding inbred japonica check varieties （CK-J） and two high-yielding hybrid indica check varieties （CK-I） were grown at Xinghua （119.57°E, 33.05°N） of Lixiahe region, Yangzhou （119.25°E, 32.30°N）of Yanjiang region, Changshu （120.46°E, 31.41°N）of Taihu Lake region, and Ningbo （121.31°E, 29.45°N） of Ningshao Plain in 2013 and 2014. The results showed that maturity dates of the 15 were later than the secure maturity date at Xinghua and 6, 14 and 15 LMYS were mature before the secure maturity date at Yangzhou, Changshu and Ningbo, respectively. One variety was identified as high-yielding variety among LMYS （HYYS） at Yangzhou, 8 HYYS in 201：3 and 9 HYYS in 2014 at Changshu, 9 HYYS at Ningbo. HYYS here referred to the variety among LMYS that was mature before the secure maturity date and had at least 8% higher grain yield than both CK-J and CK-I at each experimental site. Grain yield of HYYS at each experimental site was about 12.0 t ha-1 or higher, and was significantly higher than CK varieties. High yield of HYYS was mainly attributed to larger sink size due to more spikelets per panicle. Plant height of HYYS was about 140 cm, and was significantly higher than check varieties. Significant positive correlations were recorded between duration from heading to maturity stage and grain yield, and also between whole growth periods and grain yield. HYYS had obvious advantage over check varieties in biomass accumulation and leaf area duration from heading to maturity stage. Comprehensive consideration about safe matudty and yield performance of LMYS at each experimental site, Taihu Lake region （representative site Changshu） and Ningshao Plain （representative site Ningbo） were thought suitable growing zones for LMYS in the lower reaches of Yangtze River. The main factors underlying high yield ofHYYS were larger sink size, higher plant height, longer duration from heading to maturity stage and whole growth periods, and higher biomass accumulation and leaf area duration during grain filling stage.

Genomic insights into hybridization in a localized region of sympatry between pewee sister species(Contopus sordidulus × C. virens) and their chromosomal patterns of differentiation

Background: The Great Plains of the United States includes a large number of hybrid and contact zones between bird species. The amount of gene flow between sister species in these zones ranges from very rare hybridization events to widespread and prevalent introgression. Some of these avian systems have been studied extensively, while others have been indeterminate of whether hybridization exists in areas of sympatry. Using genomic-level approaches allows investigation of genomic patterns of hybridization and gene flow between species—or lack thereof.Methods: We investigated a narrow zone of sympatry in Nebraska, USA between pewee species(Contopus sordidulus and C. virens), for which no hybridization has been confirmed. We used thousands of single nucleotide polymorphisms to identify potential hybridization and investigate genomic patterns of differentiation between these two species.Results: We found evidence of multiple hybrid individuals in the contact zone. Little genomic variation was fixed between species, but a large proportion had differentiated allele frequencies between species. There was a positive relationship between genetic differentiation and chromosome size.Conclusions: We provided the first conclusive evidence of hybridization between C. sordidulus and C. virens, in a region where secondary contact likely occurred due to human disturbance and habitat modification. The genomic patterns of differentiation affirm that these species split in the relatively recent past. Finally, the relationship of chromosome size and genetic differentiation may have resulted from differential rates of chromosomal recombination in songbirds and genetic differentiation between species largely due to genetic drift(possibly in concert with selection).

“灰色地带”竞争:概念泛化与实践复杂化

“灰色地带”竞争是当前国际安全领域非常突出的现象,也是防务研究的一大热门议题。然而,现有的研究过于泛化和标签化,严重阻碍了研究的深入。本文系统梳理分析“灰色地带”竞争流行的大背景及研究的缘起,辨析“灰色地带”竞争的各类概念,提出“灰色地带”竞争若要作为一个相对确定的概念,必须同时满足灰色目标、灰色形态和灰色手段的“三灰”标准。由于时代变迁、制度演进和技术发展等方面的因素,以及海洋空间行动及规则的先天模糊性,当前的海上摩擦具有更鲜明的“灰色地带”竞争的特征。在此基础上,本文以海上“灰色地带”竞争为例,详细分析东亚域内域外国家在海上竞争中使用的四类主要灰色手段,以及它们与传统手段间的差异。

基于多模式分解和多支路并行残差网络的特高压三端混合直流输电线路故障区域诊断

特高压三端混合直流输电线路发生接地故障时,故障电气量变化存在很强的随机性和非线性,在噪声干扰下其规律性更弱,很难快速、准确地提取故障特征以诊断故障区域。鉴于此,提出一种集电流波形特征提取和故障区域诊断为一体的诊断模型。分析不同区域故障时的电流波形特点,利用数学机理不同的3种算法同时分解故障电流,避免一些容易混叠的模态子序列在单一分解方法中逃逸。利用多支路并行残差网络迅速地挖掘分解分量的多尺度空间耦合交互特征,并结合门控循环单元网络模块,进一步提取故障电流的时间耦合特征,使得特征得到显著增强。利用麻雀搜索算法优化该模型的关键参数,构建充分适应电网故障诊断的网络结构,实现故障区域的快速诊断。仿真结果表明,该方案有着较高的灵敏性、较强的抗干扰能力,满足直流保护的可靠性和速动性要求。

草地贪夜蛾迁飞气象预报方法探索及应用

为了准确预报害虫的迁飞轨迹,将天气预报技术应用于迁飞性害虫的预测预报,基于天气预报平台,利用欧洲中心中短期气象数值预报产品以及大气环流形势及低层风动力对草地贪夜蛾(Spodoptera frugiperda)的迁飞路径、迁入时间(包括首见日及高峰日)、落区等进行预报,并基于2021年草地贪夜蛾迁飞的2次典型预报案,分析2021年草地贪夜蛾春季北迁至湖北(首见日)以及秋季南迁回湖北(高峰日)的典型天气过程以及迁飞层气象要素场,运用HYSPLIT轨迹模型模拟迁飞后向轨迹,再利用草地贪夜蛾田间监测数据、测报灯监测数据以及迁飞轨迹对预报结论进行验证。结果显示,2次典型预报案例的预报结论与草地贪夜蛾田间监测数据及测报灯监测数据以及轨迹模拟的情景吻合度较好,草地贪夜蛾迁入时间、落区及路径预报基本正确。研究表明,将天气预报技术应用于迁飞性害虫的预报具有实际可行性。

多类型地震仪器联合采集技术在复杂区的应用与展望

近年来,随着油气勘探程度的不断深入,国内各探区开展了一系列针对复杂地表、复杂地下地质目标的技术攻关,而以“两宽一高”为特征的大道数高精度物探技术是重要手段之一。在实际勘探作业过程中,由于实时带道能力、复杂地表适应性差等方面的限制,传统有线地震仪器已无法满足大道数、高效率和高质量地震数据采集的需求。新近出现的无缆式地震仪器采用的自主采集、数据本地存储工作方式可不受实时采集道数的限制,且能够很好地解决复杂地表区的排列布设难度大的问题,但无法实现采集数据的现场实时下载和质控,数据交付相对滞后。为突破传统使用单一类型地震仪器带来的效率和质量瓶颈,本文给出基于卫星授时的多类型地震仪器联合采集技术的工作原理、作业流程和技术关键点,并以渤海湾盆地冀中坳陷探区的某项目为例阐述该勘探作业新方式的技术优势和应用效果。最后,结合地震勘探需求对多类型地震仪器联合采集技术的应用前景进行了讨论和总结。

基于T区中低频衰减特性构成方向元件的特高压三端混合直流输电线路单端方向保护研究

将保护装置安装在T区两侧,基于T区中低频衰减特性构成方向元件,提出一种特高压三端混合直流输电线路单端方向保护方法。分析特高压三端混合直流输电系统整流侧、T区以及线路末端逆变侧三端边界频率特性,发现T区边界对故障电流暂态信号中低频分量有一定的衰减作用、整流侧边界和线路末端逆变侧边界对故障电流暂态信号高频分量有明显衰减作用。利用小波分解,根据T区两侧线路暂态电流中低频能量差判断故障方向,并提出故障方向判据。当T区左侧发生故障时,利用线路L1末端所检测到的高频暂态电流能量与低频暂态电流能量的比值来判别整流侧区内、外故障;当T区右侧发生故障时,利用线路L2首端所检测到的高频暂态电流能量与低频暂态电流能量的比值来判别线路末端逆变侧区内、外故障;T区发生故障时,判定为线路区外故障。给出基于T区中低频衰减特性构成方向元件的特高压三端混合直流输电线路单端方向保护方案,最后在PSCAD/EMTDC仿真平台搭建昆柳龙特高压三端混合直流输电系统模型并对所提保护方法进行验证,仿真表明该文所提保护方法能实现特高压三端混合直流输电线路全线速动保护。

移动式固体氧化物燃料电池系统集成技术研究现状与进展

固体氧化物燃料电池(Solid Oxide Fuel Cell,SOFC)是一种能量转换装置,可以通过电化学反应将燃料中的化学能直接转换为电能。目前,SOFC大多被视为固定式发电技术,然而因其具有燃料灵活性、高效率和高能量密度等特点,在移动式发电领域如辅助动力、无人机动力、远程电源等也具有广阔应用前景。与固定式SOFC应用相比,移动式SOFC研究进展起步相对较晚,技术较不完善。移动式SOFC系统通常包括电堆、重整器、供气装置、尾燃器、换热器和储能组件等核心组件。开发SOFC移动系统需要考虑系统的鲁棒性、易用性以及发电能力等,而移动式SOFC系统部件相对较复杂,这些部件的耦合匹配特性又会显著影响系统的紧凑性、启动特性及体积/质量功率密度。从热特性、启动策略及高功率密度混合动力系统集成等方面对国内外移动式SOFC系统集成技术的研究进展进行综述。最后,基于对现有研究成果的总结提出了未来移动式SOFC系统集成中存在的挑战,及在材料与工艺的改进、新型启动策略和混合系统设计与优化等方面的发展方向。

基于混合相位的多平面全息显示

在计算全息术中,基于层析法实现多平面全息显示是最常用的方法之一。针对层析法中多个平面之间存在串扰的问题,本文结合随机相位和二次相位的优点,提出了一种基于混合相位的多平面全息显示方法。首先,选择合适的权重因子生成混合相位代替随机相位作为初始相位。利用迭代傅里叶变换算法进行迭代后,将获得的每个子全息图与具有不同重建距离的菲涅尔波带片叠加,接着将每个全息图以复振幅叠加,获取相位后得到纯相位全息图,从而将分层图像重构于指定的平面上。利用硅基液晶空间光调制器搭建多平面全息显示系统开展了相关的光学实验。实验结果表明,与基于随机相位的方法相比,本文方法提高了结构相似性参数(最高可达4.6%),减弱了多个全息重构平面之间的串扰,提高了多平面全息显示的再现质量。

基于超声检测的双组织盘件过渡区识别

针对具有复杂晶粒尺寸分布的航空发动机盘件难以进行过渡区尺寸评价的问题,提出了利用超声检测技术评价其过渡区边界的方法。首先通过超声C扫描检测航空发动机双组织盘件;然后通过均值滤波对C扫描结果进行预处理;最后利用提出的边界识别算法提取C扫描结果中的过渡区边界,进而实现双组织盘件过渡区边界尺寸和位置的定量评价。试验结果表明,采用所提出的边界识别方法提高了双组织盘件过渡区边界评价的准确率和效率。

福建两系杂交稻制种安全高产的精细气候适宜性区划

利用福建省67个国家气象观测站1971-2020年气象资料以及地理信息资料、两系杂交稻制种基地调查资料,构建了两系杂交稻制种育性转换敏感期气候风险模型与风险等级指标、扬花授粉期天气综合危害指数模型与等级指标两个安全期气候区划指标,选择不育系育性转换起点温度23℃开展研究,基于两系杂交稻制种气候适宜性分区等级标准,采用多层复合方法,开展基于GIS的福建省两系杂交稻制种安全高产精细气候适宜性区划。结果表明:育性敏感期安排在7月上旬-下旬、7月中旬-8月上旬,扬花授粉期安排在8月上旬-中旬,适宜区分布在福建北部、西南部等县市海拔300m以下的区域,次适宜区分布在福建北部、西南部等县市海拔300-500m的区域;育性敏感期安排在7月下旬-8月中旬、8月上旬-下旬,扬花授粉期8月下旬-9月上旬,适宜区分布在福建北部、西南部等县市海拔400m以下的区域,次适宜区分布在福建北部、西南部等县市海拔400-500m的区域;育性敏感期安排在7月上旬-8月下旬,扬花授粉期安排在8月上旬-9月上旬,低适宜区分布在海拔500-1000m的区域,不适宜区分布在海拔1000m以上区域。

毛乌素沙地柠条群体分子生态学初步研究:RAPD证据

毛乌素沙地柠条群体是一个杂种带。为了进一步阐明分子变异和基因流与生境或生态过渡带的联系，应用ＲＡＰＤ标记开展了柠条群体的分子生态学研究。根据ＲＡＰＤ数据利用Ｓｈａｎｎｏｎ信息指数估计了６个柠条群体的遗传多样性，发现大部分的分子变异存在于柠条群体之内（８２．４％），只有少部分的分子变异存在于群体之间（１７．６％）。又利用Ｎｅｉ指数统计了ＲＡＰＤ数据，也证实了大部分的遗传变异存在于群体之内。柠条锦鸡儿群体与中间锦鸡儿群体的遗传分化系数和遗传距离都很小。以上结果都肯定了柠条群体间和种间的基因流动。无论是从多态位点比率还是群体的遗传多样性来看，硬梁和硬梁覆沙群体是最小的，滩地覆沙群体则具有较高的水平。某些ＲＡＰＤ扩增片段的频率在柠条群体间有规律的变化也许具有着特殊的生态学意义，更可能是中性突变的随机固定。根据以上研究可以得出下列结论：①通过比较Ｓｈａｎｎｏｎ指数和Ｎｅｉ指数的统计结果，可以认为，对于异交植物来讲，Ｓｈａｎｎｏｎ指数在统计ＲＡＰＤ数据方面有用。②毛乌素沙地柠条群体之间存在着强大的基因流。

毛乌素沙地锦鸡儿（Caragana）种群种子蛋白多样性及其生物学意义

应用多种聚丙烯酰胺凝胶电泳方法对纯化的锦鸡儿种子球蛋白和清蛋白进行分离和分子量测定。占总蛋白７０％左右的球蛋白包括３个不同分子量的蛋白，它们由相同的２１个亚基组成，说明是不同的聚合态。清蛋白在ＰＡＧＥ和ＳＤＳＰＡＧＥ中部分出约２０种成分。全蛋白ＰＡＧＥ结果表明最主要的球蛋白和若干清蛋白在种群内和种群间有高水平的多态性，至少有４个可能的位点编码６个蛋白。ＳＤＳＰＡＧＥ结果表明全蛋白有约５０个不同分子量的单体，其中大多数是变异的。记录了其中１７个单体的变异，初步推测由１３个位点编码。从全部１０个种群３３７份样品的ＰＡＧＥ和３３８份样品的ＳＤＳＰＡＧＥ结果计算出２３个蛋白或单体的分布频率，进一步统计出各项种群遗传结构参数。数据表明毛乌素沙地锦鸡儿的全部遗传多样性中９０％以上存在于群体内，群体间只占７．６％，说明种群间存在强大的基因而。同一植株不同种子存在不同种子蛋白和单体成分，更进一步证明锦鸡儿的异交性。蛋白质的高水平多样性及其空间分布格局证实了所报道的形态变异的结果，说明毛乌素地区的锦鸡儿的确构成一个杂种带。