GUIDE FOR AUTHORSOA

<正>Introduction Types of paper Contributions falling into the following categories will be considered for publication:original articles,review articles,short letters,modelling/theory and methods articles,rapid reports and special thematic issues.Please ensure that you select the appropriate article type from the list of options when making your submission.Authors contributing to special issues should ensure that they select the special issue article type from this list.     

GUIDE FOR AUTHORSOA

<正>Introduction Types of paper Contributions falling into the following categories will be considered for publication:original articles,review articles,short letters,modelling/theory and methods articles,rapid reports and special thematic issues.Please ensure that you select the appropriate article type from the list of options when making your submission.Authors contributing to special issues should ensure that they select the special issue article type from this list.     

Distribution and conservation of near threatened plants in ChinaOA

Plants classified as Near Threatened(NT) are at high risk of becoming threatened because of anthropogenic interference and climate change.Especially in conservation efforts,such species have however long been overlooked.Here,we obtained 98,419 precise occurrence points for 2442 NT plants in China,and used species richness,species complementarity,and weighted endemism that consider all,endemic and narrow-ranged species in order to identify the diversity hotspots of NT plants.Then we evaluated the...     

Insights into cryptic speciation of quillworts in ChinaOA

Cryptic species are commonly misidentified because of high morphological similarities to other species.One group of plants that may harbor large numbers of cryptic species is the quillworts(Iso?tes spp.),an ancient aquatic plant lineage.Although over 350 species of Iso?tes have been reported globally,only ten species have been recorded in China.The aim of this study is to better understand Iso?tes species diversity in China.For this purpose,we systematically explored the phylogeny and evolution ...     

Applying image clustering to phylogenetic analysis:A trialOA

<正>Phylogenetic studies have increased in recent years,largely due to rapid developments in sequencing techniques (Tucker et al.,2017).However,molecular phylogenetic studies rely on collecting biomaterials,which limits their applicability to many,especially small,rare plants,or inaccessible plants.Recently,image classification using supervised or semi-supervised approaches (Dyrmann et al.,2016;W?ldchen et al., 2018;Draper et al.,2020;     

Coryphoid palms from the K-Pg boundary of central India and their biogeographical implications:Evidence from megafossil remainsOA

Ten palm leaf impressions are documented from the latest Maastrichtian(late Cretaceous) to early Danian(earliest Paleocene) sediments(K-Pg,c.66-64 Ma) of the Mandla Lobe of the Deccan Intertrappean Beds,Madhya Pradesh,central India.The palmate leaf shape along with a definite wellpreserved costa support their placement in the subfamily Coryphoideae of the family Arecaceae.We place all recovered palm leaf specimens in the fossil genus Sabalites,report seven species of coryphoid palms and describe...     

Phyllosphere eukaryotic microalgal communities in rainforests:Drivers and diversityOA

Phyllosphere algae are common in tropical rainforests,forming visible biofilms or spots on plant leaf surfaces.However,knowledge of phyllosphere algal diversity and the environmental factors that drive that diversity is limited.The aim of this study is to identify the environmental factors that drive phyllosphere algal community composition and diversity in rainforests.For this purpose,we used single molecule real-time sequencing of full-length 18S rDNA to characterize the composition of phyllos...     

Pre-and post-pollination barriers between two exotic and five native Sagittaria species:Implications for species conservationOA

Anthropogenic introduction of species has resulted in a breakdown of geographical barriers and hybridization in previously allopatric species.Thus,examining hybridization proneness of exotic species contributes to revealing its potential threat.Moreover,reproductive barriers may be strengthened or weakened due to long-term geographical isolation for these newly sympatric species.However,few studies have evaluated multiple barriers between alien and native species.In this study,we quantified the ...     

Statistical analysis of the migration component of genetic drift

Statistical methods are introduced for analysis of the migration component of genetic drift, i.e., of the stochastic changes that affect allele frequencies during migration between local groups. Attention focuses on alpha M, a parameter that measures the extent to which this component of drift departs from the ideal of independent random sampling, and which can be interpreted as a measure of the extent to which migration is kin-structured. It is shown that alpha M can be estimated from genetic data, even in the absence of information about the genealogical relationships of migrants, and Monte-Carlo simulations are used to approximate the sampling distribution of the estimator under the null hypothesis of independent random sampling. Application of these methods to data from the Aland Islands, Finland, shows that the migration pattern there is consistent with the hypothesis of independent random sampling.     

Genetic variability in Plantago species in relation to their ecology

Summary Populations of the three Plantago species P. major, P. lanceolata and P. coronopus were scored for allozyme variability. They showed normal variability levels compared with other, similar plant species. Differentiation among populations appeared to be rather low in comparison with other species, probably due to a considerable amount of long distance seed transport. In order to be able to make an analysis of small-scale gene flow, all (sub)populations were critically checked for the existence of population structure equilibrium. The allozyme variation was tested for neutrality by testing homogeneity of F values among loci: between populations (Lewontin-Krakauer test) and within populations. No systematic deviations from the prediction of the neutral theory could be established. From the population structure analyses, little gene flow in the species P. major (with high selfing levels) and P. coronopus could be concluded, whereas P. lanceolata showed relatively high levels of gene flow. The degree of homozygosity in the latter species was too high to explain with the available data. In P. coronopus, on the other hand, an unusually high number of heterozygotes were observed.Grassland Species Research Group Publication No. 73     

栗疫病菌群体的遗传结构

采用聚丙烯酸胺凝胶电泳方法,从栗疫病菌Cryphonectriaparasitica的18种酶体系中筛选到9种分辨率高的同工酶。对同工酶的检测结果表明,在中国的北京、辽宁、江西、福建及意大利、美国、日本共7个群体的115个栗疫病菌菌株中,多酚氧化酶（PPO）、过氧化物酶（POX）、细胞色素氧化酶（CCO）、乙醇脱氢酶（ADH）、超氧化物歧化酶（SOD）为单态性;α-酯酶（α－EST）、β-酯酶（β-EST）、苹果酸脱氢酶（MDH）、苹果酸酶（ME）为多态性,分别具有10、7、3、3种电泳表现型。通过9种同工酶的凝胶电泳分析,对栗疫病菌的群体结构进行了比较。中国地区4个群体间的遗传相似性较大,与美国、意大利、日本群体间的相似性较小;美国、意大利群体间的遗传相似性较大,且它们与日本群体间的相似性大于与中国各群体间的相似性,这一结果表明美国的栗疫苗可能是从日本传人的。病菌群体的遗传变异率为of60,其中83．1％由群体内的变异引起,16．9％由群体间的差异引起。群体间的基因流动值为246。     

杨树和葡萄UBX蛋白质家族分析

UBX（泛素调控X因子）蛋白质家族在泛素化相关的过程中起着重要的作用,如细胞周期调控、转录调控、信号转导、发育、胁迫响应、细胞程序性死亡、内吞作用和DNA修复。然而,到目前为止。UBX家族在杨树和葡萄中还没有被研究过。为了更好的弄清这两个植物的UBX家族,我们对UBX的基因结构、染色体位置、基因重复、系统发育关系作了分析。该研究对葡萄和杨树的UBX蛋白质家族作了第一个系统的分析。基因的外显子／内含子结构和蛋白质基序组成在同一个组里相对比较保守。基因重复分析表明．串联重复和片段重复对于杨树和葡萄的UBX基因家族的扩张有一定贡献,基因缺失在UBX基因家族的扩张过程中也发生了作用。本研究为UBX蛋白质功能的研究奠定了基础。     

Genetic homogeneity between populations of cotton bollworm from Xinjiang,China

We studied the population structure of cotton bollworm (CBW), Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), in Xinjiang, the largest cotton-growing region in China, using a fragment of cytochrome c oxidase subunit I (COI) gene. Alignments of all 192 COI sequences revealed 28 haplotypes including 23 in southern Xinjiang, 5 in eastern Xinjiang and 13 in northern Xinjiang. Negative and significant values of neutrality tests for the Tajima's D and Fu's FS parameters, combined with the high values of haplotype diversity (H_d), low values of nucleotide diversity (π) and a high number of low frequency haplotypes indicated a recent demographic expansion of Xinjiang CBW populations. Analysis of molecular variation (AMOVA) indicated low and non-significant genetic structure, regardless of geographical scale or crop, with most of genetic variation occurring within local CBW populations. Pairwise F_ST analyses also indicated low genetic differentiation. This demographic event and high gene flow could be responsible for the low genetic structure currently found. CBW populations in Xinjiang need to be considered as one panmictic unit in its management, especially for the design of refuges to delay the development of resistance by this migratory pest to transgenic Bt (Bacillus thuringiensis) cotton.     

Optimal Gene Trees from Sequences and Species Trees Using a Soft Interpretation of Parsimony

Gene duplication and gene loss as well as other biological events can result in multiple copies of genes in a given species. Because of these gene duplication and loss dynamics, in addition to variation in sequence evolution and other sources of uncertainty, different gene trees ultimately present different evolutionary histories. All of this together results in gene trees that give different topologies from each other, making consensus species trees ambiguous in places. Other sources of data to generate species trees are also unable to provide completely resolved binary species trees. However, in addition to gene duplication events, speciation events have provided some underlying phylogenetic signal, enabling development of algorithms to characterize these processes. Therefore, a soft parsimony algorithm has been developed that enables the mapping of gene trees onto species trees and modification of uncertain or weakly supported branches based on minimizing the number of gene duplication and loss events implied by the tree. The algorithm also allows for rooting of unrooted trees and for removal of in-paralogues (lineage-specific duplicates and redundant sequences masquerading as such). The algorithm has also been made available for download as a software package, Softparsmap.     

Evidence for gene flow differs from observed dispersal patterns in the Humboldt penguin, Spheniscus humboldti

The Humboldt penguin, once common throughout its range, is today listed as Vulnerable by the IUCN. Mark-recapture and telemetry studies indicate that adult Humboldt penguins are sedentary, suggesting strong genetic differentiation between colonies. We developed genotypes for 336 individuals at 12 microsatellite loci sampled at four different localities spanning the entire range of this species. Results show that long-term gene flow has occurred but appears to be affected by geographic distance as pairwise F _ST comparisons involving the colony at Punta San Juan (Peru) and the two colonies at Algarrobo (central Chile) and Puñihuil (southern Chile) are significant. Bayesian estimates of recent migration rates indicate substantial dispersal among all colonies. Despite the dramatic decline in numbers, we did not observe a bottleneck in any population. Furthermore, we did not detect a founder effect in the recently discovered colony at Puñihuil. As our indirect estimates signal strong gene flow between populations, we suggest that Humboldt penguin colonies need to be managed as a metapopulation rather than as discrete management units.     

Density-dependent migration and human population structure in historical Massachusetts

Studies of population structure often focus on the effects of population size and migration rates on genetic variation. Few studies, however, have investigated the relationship between these two factors. The purpose of this paper is to determine the extent to which migration (and gene flow) is density-dependent (that is, affected by population size) for populations in historical Massachusetts. Data from 4,859 marriage records were analyzed from four populations in north-central Massachusetts during the time period 1741 to 1849. These data were placed into 29 samples defined in terms of population and time cohort. Within each cohort the overall exogamy rate was computed along with three estimates of gene flow based on marital migration: local migration (k), long-distance migration (m), and effective migration rate (me). Three samples show unusually low rates that reflect the history of settlement. Regression analyses were used with the remaining samples, and they show nonlinear density-dependent migration that is unrelated to temporal trends. Migration is highest in samples with small population sizes (less than 800) and large population sizes (greater than 1,600). Migration is lowest in medium-sized populations. Two processes are suggested to explain this curvilinear relationship of migration and population size. In small populations, the lack of suitable potential mates and/or availability of settled land leads to an increase in migration into the population. As population size increases, this migration decreases. After populations reach a certain size, migration increases again, most likely reflecting the economic pull of larger populations. These patterns could act to enhance, or counter, genetic drift, depending on the direction of density dependence.