我国云南西部玉山竹属一新种及粗毛箭竹花部特征补记

发表了产于云南西部的玉山竹属一新种永德玉山竹(Yushania yongdeensis Yi et J. Y. Shi)。补充记载了雪山箭竹(Fargesia lincangensis Yi)的花部特征。     

Preliminary investigations of hybridization/reticulate evolution in Guaranidrilus (Enchytraeidae: Oligochaeta)

The identification of gut diverticula at 7/8 as a synapomorphy and recognition of all taxa of Guaranidrilus has been obscured by losses of gut diverticula within the lineage. The homoplastic occurrence of basally unpaired peptonephridia in some enchytraeid species has similarly obscured the limits of Hemienchytraeus. Taxa with unpredictable relationships, morphogenic irregularities in some reproductive structures, and, apparently, modified modes of reproduction, suggest the possibilities of hybridization between taxa with both close and distant relationships.     

Chloroplast DNA evidence for reticulate evolution in Eucalyptus (Myrtaceae)

Four highly differentiated chloroplast DNA (cpDNA) lineages were identified in the forest tree species Eucalyptus globulus Labill. (Myrtaceae) in Australia using restriction site polymorphisms from Southern analysis. The cpDNA variation did not conform with ssp. boundaries, yet there was a strong geographical pattern to the distribution of the lineages. One lineage (C) was geographically central and widespread, whereas the other three lineages were found in peripheral populations: Western (W), Northern (N) and Southern (S). Thirteen haplotypes were detected in E. globulus , seven of which belonged to clade C. At least three of the cpDNA lineages (C, N and S) were shared extensively with other species. On the east coast of the island of Tasmania, there was a major north–south difference in cpDNA in the virtually continuous distribution of E. globulus . Northern populations harboured haplotypes from clade C while southeastern populations harboured a single haplotype from clade S. This difference was also reflected in several co-occurring endemic species. It is argued that the extensive cpDNA differentiation within E. globulus is likely to originate from interspecific hybridization and 'chloroplast capture' from different species in different parts of its range. Superficially, this hybridization is not evident in taxonomic traits; however, large-scale common garden experiments have revealed a steep cline in quantitative genetic variation that coincides with the haplotype transition in Tasmania. Our cpDNA results provide the strongest evidence to date that hybridization has had a widespread impact on a eucalypt species and indicate that reticulate evolution may be occurring on an unappreciated scale in Eucalyptus .     

Flow cytometry confirms reticulate evolution and reveals triploidy in Central European Diphasiastrum taxa (Lycopodiaceae, Lycophyta)

Background and Aims

Interspecific Diphasiastrum hybrids have been assumed to be homoploid and to produce well-formed spores serving sexual reproduction. If this were the case, forms intermediate between hybrids and parents or hybrid swarms should be expected. The purpose of this study was: (1) to check whether homoploidy consistently applies to the three hybrids throughout their Central European range; (2) to examine whether their genome sizes confirm their parentage as assumed by morphology; and (3) to perform a screening for detection of ploidy levels other than diploid and variation in DNA content due to backcrossing.

Methods

Flow cytometry was used first to measure the relative DNA values [with 4′,6-diamidino-2-phenylindole (DAPI) staining] and ploidy level as a general screening, and secondly to determine the absolute DNA 2C values [with propidium iodide (PI) staining] in a number of selected samples with the main focus on the hybrids.

Key Results

A considerable variation of DNA 2C values (5·26–7·52 pg) was detected between the three European Diphasiastrum species. The values of the diploid hybrids are highly constant without significant variation between regions. They are also intermediate between their assumed parents and agree closely with those calculated from their putative parents. This confirms their hybrid origin, assumed parentage and homoploid status. Considerably higher DNA amounts (9·48–10·30 pg) were obtained for three populations, suggesting that these represent triploid hybrids, an interpretation that is strongly supported by their morphology.

Conclusions

Diploid hybrids have retained their genetic and morphological identites throughout their Central European range, and thus no indications for diploid backcrossing were found. The triploid hybrids have probably originated from backcrossing between a diploid gametophyte of a hybrid (derived from a diplospore) and a haploid gametophyte of a diploid parental species. By repeated crossing events, reticulate evolution patterns arise that are similar to those known for a number of ferns.     

Exploring the reticulate evolution in the Asplenium pekinense complex and the A. varians complex (Aspleniaceae)

The Asplenium pekinense complex mainly comprises one diploid, A. sarelii Hook. (rare), one autotetraploid, A. pekinense Hance (best known and very common), and shares two allotetraploids, A. anogrammoides Christ (common but often misidentified) and A. altajense (Komarov) Grubov (rare and endemic) with the A. varians complex. The latter is further constituted by two diploids, A. tenuicaule Hayata (widespread) and A. semivarians Viane & Reichstein (rare), as well as other three tetraploids, A. kansuense Ching (barely known), A. varians Wallich ex Hooker & Greville (well‐known, relatively common, and morphologically variable), and A. kukkonenii Viane & Reichstein (rare and often misidentified). These two species complexes are notorious for their taxonomic difficulty based on general morphology, which is mainly caused by their history of reticulate evolution. Here, we collected most species within the two complexes, and obtained ploidy information by spore size measurement and flow cytometry investigation. Phylogenetic analyses using DNA markers representing maternally inherited chloroplast and biparentally inherited nuclear genomes helped to reconstruct the reticulate evolution history. The present results support previous hypotheses that A. sarelii is the ancestor of both A. pekinense and A. anogrammoides, as well as that A. tenuicaule is the common progenitor of A. anogrammoides, A. varians, and A. kukkonenii. We also unraveled the autotetraploid origin of A. kansuense from A. tenuicaule for the first time, and found that A. altajense shares essentially identical genomes with A. anogrammoides.     

Apomixis and reticulate evolution in the Asplenium monanthes fern complex

Background and Aims

Asexual reproduction is a prominent evolutionary process within land plant lineages and especially in ferns. Up to 10 % of the approx. 10 000 fern species are assumed to be obligate asexuals. In the Asplenium monanthes species complex, previous studies identified two triploid, apomictic species. The purpose of this study was to elucidate the phylogenetic relationships in the A. monanthes complex and to investigate the occurrence and evolution of apomixis within this group.

Methods

DNA sequences of three plastid markers and one nuclear single copy gene were used for phylogenetic analyses. Reproductive modes were assessed by examining gametophytic and sporophyte development, while polyploidy was inferred from spore measurements.

Key Results

Asplenium monanthes and A. resiliens are confirmed to be apomictic. Asplenium palmeri, A. hallbergii and specimens that are morphologically similar to A. heterochroum are also found to be apomictic. Apomixis is confined to two main clades of taxa related to A. monanthes and A. resiliens, respectively, and is associated with reticulate evolution. Two apomictic A. monanthes lineages, and two putative diploid sexual progenitor species are identified in the A. monanthes clade.

Conclusions

Multiple origins of apomixis are inferred, in both alloploid and autoploid forms, within the A. resiliens and A. monanthes clades.     

拉沙山黑白仰鼻猴食用竹叶的化学成分分析

黑白仰鼻猴常年采食竹类叶片,竹子是其重要的食物资源之一。本文通过对拉沙山黑白仰鼻猴生境中空心箭竹和马斯箭竹竹叶化学成分进行分析,探讨其采食原由。2011年3月至2012年2月,共采集了21份竹子样品,分析其粗蛋白、粗脂肪、总糖、粗纤维、灰分、钙和总磷等化学成分。结果表明:两种竹叶的选择主要受高钙、高能量和低Ca/P的影响。尽管空心箭竹与马斯箭竹的化学成分无差异,但是影响黑白仰鼻猴食物选择的主要因素有所不同,这可能与竹子化学成分的季节性变化有关。结合前人对该猴群非竹类食物的研究结果,黑白仰鼻猴采取在满足蛋白质、脂肪等常量营养物质需求基础上优先保证磷、钙和能量摄入的觅食策略。竹类等猴群重要食物资源应该受到重点保护,同时也是未来食物资源恢复的首选物种。     

Chloroplast DNA phylogeny, reticulate evolution, and biogeography of Paeonia (Paeoniaceae)

The coding region of the mat K gene and two intergenic spacers, psb A-trn H and trn L(UAA)-trn F(GAA), of cpDNA were sequenced to study phylogenetic relationships of 32 Paeonia species. In the psb A-trn H intergenic spacer, short sequences bordered by long inverted repeats have undergone inversions that are often homoplasious mutations. Insertions/deletions found in the two intergenic spacers, mostly resulting from slipped-strand mispairing, provided relatively reliable phylogenetic information. The mat K coding region, evolving more rapidly than the trnL-trn F spacer and more slowly than the psb A-trn H spacer, produced the best resolved phylogenetic tree. The mat K phylogeny was compared with the phylogeny obtained from sequences of internal transcribed spacers (ITS) of nuclear ribosomal DNA. A refined hypothesis of species phylogeny of section Paeonia was proposed by considering the discordance between the nuclear and cpDNA phylogenies to be results of hybrid speciation followed by inheritance of cpDNA of one parent and fixation of ITS sequences of another parent. The Eurasian and western North American disjunct distribution of the genus may have resulted from interrruption of the continuous distribution of ancestral populations of extant peony species across the Bering land bridge during the Miocene. Pleistocene glaciation may have played an important role in triggering extensive reticulate evolution within section Paeonia and shifting distributional ranges of both parental and hybrid species.     

Phylogenomics reveals a new 'megagroup' including most photosynthetic eukaryotes

Advances in molecular phylogeny of eukaryotes have suggested a tree composed of a small number of supergroups. Phylogenomics recently established the relationships between some of these large assemblages, yet the deepest nodes are still unresolved. Here, we investigate early evolution among the major eukaryotic supergroups using the broadest multigene dataset to date (65 species, 135 genes). Our analyses provide strong support for the clustering of plants, chromalveolates, rhizarians, haptophytes and cryptomonads, thus linking nearly all photosynthetic lineages and raising the question of a possible unique origin of plastids. At its deepest level, the tree of eukaryotes now receives strong support for two monophyletic megagroups comprising most of the eukaryotic diversity.     

Phylogenomics and molecular evolution of foot-and-mouth disease virus

This report describes the use of Bayesian methods to analyze polyprotein coding region sequences (n = 217) obtained from GenBank to define the genome-wide phylogeny of foot and mouth disease virus (FMDV). The results strongly supported the monophyly of five FMDV serotypes, O, A, Asia 1, C, and SAT 3, while sequences for the two remaining FMDV serotypes, SAT 1 and SAT 2 did not separate into entirely distinct clades. The phylogenomic tree revealed three sister-group relationships, serotype O + Asia 1, A + C, and SAT 1 + 3 + 2, with a new branching pattern: {[(O, Asia 1), (A, C)], (SAT 1, 2, 3)}. Within each serotype, there was no apparent periodic, geographic, or host species influence on the evolution of global FMDVs. Analysis of the polyprotein coding region of these sequences provided evidence for the influence of purifying selection on the evolution of FMDV. Using a Bayesian coalescent approach, the evolutionary rate of FMDV isolates that circulated during the years 1932-2007 was estimated to be 1.46 × 10(-3) substitutions/site/year, and the most recent common ancestor of the virus existed approximately 481 years ago. Bayesian skyline plot revealed a population expansion in the early 20(th) century that was followed by a rapid decline in population size from the late 20(th) century to the present day. These findings provide new insights into the mechanisms that impact on the evolution of this important livestock pathogen.     

Analysis of reticulate relationships within the Daphnia longispina species complex. Allozyme phenotype and morphology

A two-step method is proposed to get reliable associations between morphology and genotype in clonal assemblages in which more than two predominantly parthenogenetic species are thought to coexist with hybrids. In dataset 1, the genetic relationships among clones of the Daphnia longispina hybrid complex from seven prealpine lakes in southern Germany were studied based on the variation at 21 enzyme loci. The spatial arrangement in the multidimensional scaling plot revealed a reticulate pattern among three presumably parental species, D. cucullata, D. galeata and D. hyalina, and three hybrid groups, D. cucullata/galeata, D. cucullata/hyalina and D. galeata/hyalina. The Got1 locus was believed to be a discriminating factor between species and hybrids (cf. Wolf and Mort, 1986). However, this locus is more variable, and 57% of the clones would have been misidentified using it. Moreover, the morphological variation within genetically defined groups is also higher than previously assumed. In dataset 2, the revision of morphological and genetic markers greatly improved the association between morphology and genotype in newly collected animals. The spatial arrangement of clones in multidimensional scaling plots and morphological asymmetries to parents suggest both, different degrees of introgression and bidirectional hybridization. Most unexpected genotypes were found in the cxh hybrid group, suggesting that F1-hybrids are fertile. The results showed (1) that the clonal diversity was very high (2) that detailed analyses of multiple morphological and allozyme markers are necessary to resolve taxonomic relationships within clonal assemblages consisting of multiple species, hybrids and differently introgressed backcrosses, and (3) that the three original species seem to have sufficient within-species recombination and a low enough rate of backcrossing to allow taxonomic identification. It must remain undecided if the present situation is locally restricted, if it is stable or represents a transient situation which could lead to either a consolidation of the three species by gradual elimination of the hybrids, to a taxonomic breakdown, or to hybrid speciation.     

Two new species of Yushania (Poaceae: Bambusoideae) from South China,with a taxonomic revision of related species

Two new species of Yushania (Poaceae, Bambusoideae, Arundinarieae) are described and illustrated from Hunan, China. Yushania longshanensis D.Z. Li & X.Y. Ye is distinguished from related species (Y. confusa, Y. angustifolia and Y. pachyclada) by having a thinner culm (0.2–0.3 cm in diameter), glabrous sheath scar, no oral setae, a large glabrous leaf blade (10–20 × 0.9–1.3 cm) and 3–4 pairs of secondary veins. Yushania stoloniforma D.Z. Li & X.Y. Ye has a distinctive scrambling habit, which differs from its putative close allies. Both of these two new species have a solitary branch at the basal nodes and can be assigned to Yushania sect. Yushania based on morphological features. Additionally, we treated Yushania gigantea T.P. Yi & L. Yang as a new synonym of Y. elevata T.P. Yi and renamed Y. microphylla T.P. Yi & L. Yang as Y. weiningensis D.Z. Li & X.Y. Ye.     

Live history evolution in Serpulimorph polychaetes: a phylogenetic analysis

The widely accepted hypothesis of plesiomorphy of planktotrophic, and apomorphy of lecithotrophic, larval development in marine invertebrates has been recently challenged as a result of phylogenetic analyses of various taxa. Here the evolution of planktotrophy and lecithotrophy in Serpulimorph polychaetes (families Serpulidae and Spirorbidae) was studied using a hypothesis of phylogenetic relationships in this group. A phylogenetic (parsimony) analysis of 36 characters (34 morphological, 2 developmental) was performed for 12 selected serpulid and 6 spirorbid species with known reproductive/developmental strategies. Four species of Sabellidae were used in the outgroup. The analysis yielded 4 equally parsimonious trees of 78 steps, with a consistency index (CI) of 0.654 (CI excluding uninformative characters is 0.625). Under the assumption of unweighted parsimony analysis, planktotrophic larvae are apomorphic and non-feeding brooded embryos are plesiomorphic in serpulimorph polychaetes. The estimated polarity of life history transitions may be strengthened by further studies demonstrating an absence of a unidirectional bias in planktotrophy-lecithotrophy transition in polychaetes.     

The enigmatic invasive Spartina densiflora: a history of hybridizations in a polyploidy context

The aim of this study was to explore the origin of the invasive Spartina densiflora by analysing samples from the native region (South America) and from a recently colonized area (California). A combination of various molecular data (chloroplast and nuclear sequences, molecular fingerprint) and ploidy level estimations was used to answer the question whether the reticulate phylogenetic pattern previously detected in S. densiflora was restricted to California, or alternatively, whether a more ancient hybrid origin preceded formation of this species in its native area. We found that this species is heptaploid in both its native and introduced range. Identification of nuclear homeologous sequences indicate that this species has a reticulate origin in its native range, involving a lineage related to the hexaploid clade formed by S. alterniflora, S.foliosa, and S. maritima, and another lineage related to the sub-Antarctic endemic S. arundinacea that provided the chloroplast genome. The samples from California displayed similar multilocus patterns to the samples from Chile, supporting the hypothesis that this species originated on the southeast American coast (Argentina), from where it eventually spread to the west coast of South America (Chile) first and to the Northern Hemisphere (California) later.     

Hiding in plain sight: Phylogenomics reveals a new branch on the Noctuoidea tree of life

We analyse anchored hybrid enrichment data from densely sampled tribes and subfamilies of Notodontidae (Prominent Moths). Notodontidae are monophyletic except for an assemblage of genera related to Thacona Walker (=Scrancia Holland), which had been recognized at either the tribal or subfamilial rank within Notodontidae. We elevate and re-describe Scranciidae stat. nov. as a family distinct from the six currently recognized noctuoid families (Noctuidae, Erebidae, Euteliidae, Nolidae, Notodontidae and Oenosandridae). Scranciidae include 22 genera comprising approximately 100 species—distributed in Africa, Asia and Australia. We re-interpret morphological synapomorphies previously proposed for Notodontidae (including Scranciidae) and for the trifid Noctuoidea more broadly. Deep-level relationships within Noctuoidea are not well resolved outside the clade comprising the four quadrifid families (Noctuidae, Erebidae, Euteliidae and Nolidae). The phylogenetic position of Scranciidae relative to Notodontidae, Oenosandridae and the quadrifids varied markedly depending on data type (amino acid vs. nucleotide) and analytical framework (maximum likelihood, multi-species coalescent and parsimony). We discuss the possible roles of missing data and short branch lengths in resolving the placement of Scranciidae. In the topology best supported by the most available data, Scranciidae are sister to the remaining Noctuoidea, highlighting their phylogenetic significance. We provide a provisional list of the genera included in Scranciidae.