Karyomorphology of some Moraceae and Cecropiaceae (Urticales)

The karyomorphology of 16 species in 13 genera representing Moraceae and Cecropiaceae was investigated in an effort to contribute to a better understanding of chromosome features and evolution in the families. All genera investigated have similar karyomorphology, but differences are found in (1) chromosome features of Interphase nucleus (simple, simple-complex, or complex chromocenter type), (2) basic chromosome number (x=13 or 14), (3) size variation (mono-or bimodial), and (4) frequencies of chromosomes with median centromeres (m-chromosome) (25–85%) and those with subterminal (or terminal) centromeres (st-chromosome) (14–69%). Comparisons with Ulmaceae as an outgroup of the remainder of Urticales suggest that the simple chromocenter type,x=14 comprising bothm- andst-chromosomes, and the monomodial karyotype are plesiomorphies in Moraceae and Cecropiaceae. Most of Moraceae and Cecropiaceae retain generalized chromosome features of the order, but have involved a few evolutionary changes in karyomorphology. Based on some detailed karyomorphological data, inter- and infrafamilial relationships are also briefly discussed.     

Karyomorphology and evolution in some Hamamelidaceae and Platanaceae (Hamamelididae; Hamamelidales)

Karyomorphology in 14 species of 12 genera representing a variation of Hamamelidaceae and in one species of Platanaceae (Platanus only) is investigated in an effort to contribute to an understanding of chromosome evolution and inter- and intrafamilial relationships. All genera investigated show similar chromosome features at resting stage and prophase, excepting that at resting stageRhodoleia shows the simple, rather than the simple-complex, chromocenter type as in other genera. At metaphase all the genera investigated of Hamamelidaceae, like other ‘lower’ Hamamelididae, have chromosomes with median centromeres (m-chromosomes), those with submedian centromeres (sm-chromosomes) and those with subterminal (or terminal) centromeres (st-t-chromosomes) at different frequencies, although frequencies ofst-t-chromosomes are always less than 33%. InPlatanus,m-chromosomes are lacking and insteadst-t-chromosomes are predominant (86%), a feature seemingly very specialized. We confirmedx=7 in Platanaceae,x=12 in Hamamelidoideae and Rhodoleioideae, andx=8 in Exbucklandioideae and Altingioideae (Hamamelidaceae). An analysis of chromosome morphology supports the hypothesis thatx=12 in the former two subfamilies is of tetraploid origin fromx=6, rather than of triploid origin fromx=8. We further give brief comments on the suprageneric classification of Hamamelidaceae that was recently proposed by Endress.     

穗花杉属的核形态及其系统位置的探讨

研究了穗花杉Amentotaxus argotaenia和云南穗花杉A.yunnanensis的核形态。它们的有丝分裂间期核都为复杂染色中心型,前期染色体为中间型,中期染色体数目均为2n=36,核型相似,均为K(2n)＝36=8m+28T,核型不对称性属于1B型,N．F．值为44。云南穗花杉的核型为首次报道。结合其它学科的资料,认为穗花杉属同榧属Torreya比较接近。     

裸蒴属的核型及三白草科四属间系统关系的探讨

本文首次报道三白草科裸蒴属中华裸蒴(Gymnotheca chinensis Decne)和白苞裸蒴(G. involucrata Pei)的染色体数目。两个种的体细胞染色体数均为2n=18,染色体基数为x=9。三白草科原始祖先的染色体基数假定为x=11,裸蒴属可能是经非整倍减少演变而来。裸蒴属间期核型属球状或棒状前染色体型。本文根据三白草科染色体研究的结果和现代地理分布格局,结合其他分枝学科的研究资料,对科下四属间的系统发育关系提出了初步假设。     

Karyomorphology of Taiwanese Begonia (Begoniaceae): taxonomic implications

 The karyomorphology of all 14 species of Taiwanese Begonia was investigated to elucidate their chromosome features and chromosomal evolution. Among all species investigated, differences in chromosome features are found in: (1) chromosome number 2n = 22, 26, 36, 38, 52, 60, 64, 82, and (2) frequencies of chromosomes with secondary, tertiary, and/or small constrictions of polyploids, ranging from 23% to 63%, which is higher than the expected value of about 9%. It is suggested that after polyploidization from the diploid species (i.e., 2n = 22 and frequencies of chromosomes with secondary, tertiary, and/or small constrictions of polyploids of about 9%), chromosome translocations occurred, followed by a decrease in chromosome number, and subsequently stabilized genomes were formed in various species in Taiwan. The karyomorphological evidence also suggested that the chromosome morphology has evolved in parallel in the begonias belonging to different sections in Taiwan. The variation in chromosomal features is more complex than the variation in floral and fruit morphologies. Karyomorphological data also supports the recognition of five new species in Taiwan: Begonia bouffordii, B. chuyunshanensis, B. pinglinensis, B. tengchiana, and B. wutaiana. Based on detailed karyomorphological analyses, the taxonomic implications, speciation, and chromosomal evolution in Taiwanese Begonia are discussed. Received: January 22, 2002 / Accepted: March 4, 2002     

鸡骨常山属三个种的核形态

研究了鸡骨常山属（Alstonia）3个种的核形态,其中盆架树（A.rostrata）的核型属首次报道,3个种的体细胞染色体数目均为2n=42,且糖胶树（A.scholaris）和鸡骨常山（A.yunnanensis）的染色体数目同前人报道的2n=44不同。盆架树的间期核和有丝分裂前期染色体分别为棒状前染色体型和中间型,核型公式为2n=42=3M＋21m＋18sm,核型不对称性类型为2A型。糖胶树的间期核和有丝分裂前期染色体分别为球状前染色体型和中间型,核型公式为2n=42=14m＋24sm＋4st,核型不对称性类型为3A型。鸡骨常山的间期核和有丝分裂前期染色体分别为复杂染色体中央粒型和中间型,核型公式为2n=42=5m＋37sm,核型不对称性类型为3B型。根据核形态结果,结合形态学特征和已有的细胞学资料,初步讨论了该属几个种的系统位置及演化趋势。     

国产毛茛科升麻属四种植物的核形态研究，并略论升麻的细胞地理

本文研究了国产四种升麻属植物(小升麻、单穗升麻、云南升麻、升麻及其变种毛叶升麻)的核 形态。除发现升麻在云南西北部地区有二倍体和四倍体两种细胞型存在外,其他类群都为二倍体。云南升麻和毛叶升麻的染色体数目和核型为首次报道。     

中国特有牛筋条属的核形态及其系统位置

报道了以３个不同居群为材料进行的拮筋条属核形态学研究结果。其间期核和前期核分别为简单染色体中心型和蹭型。染色体长度界于１．６６μｍ至０．８７μｍ之间,核型公式为２＝２８ｍ＋６ｓｍ,核型分类为１Ａ型。相同的染色体基数及其与苹果亚科成员近似的核型,支持将牛条属置于苹果亚科,而不赞同将其归属于李亚科或另立亚科的观点。     

Karyomorphology of four species in Cimicifuga (Ranunculaceae) from China,with some cytogeographical notes on C. foetida

In this paper, four species of the genus Cimicifuga L. from China(C. acerina, C. simplex, C. yunnanensis, C. foetida var. foetida and C. foetida var. velutina ) were karyomorphologically investigated. All the taxa studied had the same chromosome number of 2n= 16 except for C. foetida var. foetida, in which a tetraploid cytotype was found to occur in northwestern Yunnan. Their karyotypes are all presented. The chromosomecounts in C. yunnanensis and C. foetida var. velutina are reported here for the first time.     

Karyomorphology of four species in Ancylostemon,Briggsiopsis and Lysionotus (Gesneriaceae)

Reported in the present paper are chromosome numbers and karyotypes of three genera of the Gesneriaceae, i.e. Ancylostemon Craib. , Briggsiopsis (Franch.) K. Y. Pan and Lysionotus D. Don. The former two genera are endemic to China. The karyotype of Ancylostemon aureus (Franch.) Burtt is formulated as 2n = 34 = 20m(1sat) + 14sm, with the same chromosome number as its allied species A. convexus Craib. This species is characterized by the interphase nucleus of complex chromocenter type and the proximal type of chromosomes in the mitotic prophase. The chromosome number of the monospecific genus Briggsiopsis is 2n = 34, the same as the lowest chromosome number reported in Briggsia. The karyotype of Briggsiopsis, which is formulated as 2n = 25m + 6sm + 3st, also seems to be primitive among the species of the two genera. Briggsiopsis is characterized by the interphase nucleus of simple-complex chromocenter type and the interstitial-gradient type of chromosomes in the mitotic prophase. The chromosome number of Lysionotus carnosus Hemsl. is the lowest reported in this genus. Its karyotype is formulated as 2n= 30 = 21m + 5sm + 3st + lt. Lysionotus serratus var. pterocaulis, with the karyotype being formulated as 2n= 32 = 2lm + 10sm + lt, has the same chromosome number as var. serratus. These two species show a remarkable differentiation of karyotypes and are characterized by the interphase nuclei of simple-complex chromocenter type and the gradient type of chromosomes in the mitotic prophase. _ .     

Genome size variation and species relationships in the genus Hydrangea

Genome size and base composition in 16 species and subspecies of the Hydrangea, a woody ornamental genus of Hydrangeaceae, were evaluated by flow cytometry in relation to their chromosome number. This is the first such study concerning the genome size of these species together with a karyotype study of the most important species, Hydrangea macrophylla subsp. macrophylla (Hortensia), from an economical point of view. The 2C DNA content ranged from 1.95 pg in Hydrangea quercifolia to 5.00 pg in Hydrangea involucrata. The base composition ranged from 39.9% GC in Hydrangea aspera subsp. sargentiana to 41.1% in Hydrangea scandens subsp. scandens (significant difference at p < 0.05). The smallest genome sizes were those of the three species originating from North or South America. Most of the species studied presented a chromosome number of 2n = 2x = 36, except for those of the section Aspereae which showed 2n = 30, 34 and 36. A primary karyotype has been made for the first time for H. macrophylla subsp. macrophylla. Phylogenetic relationships between species, the origin of chromosome number and an exploration of the genetic diversity within the genus are discussed. Received: 24 July 2000 / Accepted: 31 October 2000     

直瓣苣苔属、筒花苣苔属和吊石苣苔属4个种的核形态学研究

本文报道了苦苣苔科直瓣苣苔属Ancylostemon、筒花苣苔属Briggsiopsis和吊石苣苔属Lysionotus 中4个种的染色体数目和核形态。凹瓣苣苔A．aureus的染色体数目为n=34,与其近缘种凸瓣苣苔 A．convexus的染色体数目相同。该种的核型公式为2n=20m(1sat)+14sm,核型类型属于2A。间期核 为复杂染色中心型(complex chromocenter type);细胞有丝分裂前期的染色体为近基型(proximal type) 我国特有单种属筒花苣苔属Briggsiopsis的间期核为简单—复杂染色中心型(simple-complex chromocenter type);细胞有丝分裂前期的染色体为中间—渐变型(interstitial—gradient type);核型公式为2n=34=25m +6sm+3st,与近缘类群——粗筒苣苔属Briggsia染色体数目2n=34,68相比,无论染色体数目还是核 型均显示比较原始的特征。吊石苣苔属的蒙自吊石苣苔L．carnosus和翅茎吊石苣苔L．serratus D． Don var．pterocaulis的核型公式分别是2n=30=21m+5sm+3st+1t和2n=32=21m+10sm+1t。核 型类型分别属于2A和2B。间期核均为简单—复杂染色中心型(simple-complex chromocenter type);细胞 有丝分裂前期的染色体为渐变型(gradient type)。     

五种中国苏铁属植物的核型分析

报道五种苏铁的染色体数目和核型,其中红河苏铁 (Cycas hongheensis)、叉孢苏铁 (C.segmentifida)和十万大山苏铁 (C.shiwandashanica) 为首次报道。     

Karyomorphology and nuclear DNA content of sixteen Ophrys L. taxa from Turkey

Karyotypes in 16 representative taxa of the Ophrys genus are compared, based on Feulgen-stained somatic metaphase chromosomes. The karyotypes of O. omegaifera subsp. israelitica, O. ulupinara, O. lycia, O. argolica subsp. lucis, O. argolica subsp. lesbis, O. climacis and O. reinholdii subsp. reinholdii are described for the first time. Karyological analyses indicate relationships among the species with respect to their asymmetry indices. All Ophrys taxa studied were diploid with 2n = 2x = 36 chromosomes. One B chromosome has been detected among the chromosomes of O. argolica subsp. lucis. All karyotypes are symmetrical, consisting of metacentric and submetacentric chromosomes. The longest chromosomes of all the investigated specimens contain a secondary constriction. It is determined that there is a correlation between the total number of chromosomes having secondary constrictions and the evolutionary development order of the taxa. Based on nuclear DNA content, analysis was carried out by flow cytometer using propodium iodide as fluorochrome, 2C nuclear DNA content of 16 Ophrys species varying between 20.80 pg (O. argolica subsp. lucis) and 23.11 pg (O. omegaifera subsp. israelitica). Karyotype asymmetry relationships are discussed according to the bidimensional scatter plots of A₁–A₂, CV_CL–CV_CI, CV_CL–M_CA and CV_CI–M_CA.     

Comparative genomics of Leishmania isolates from Brazil confirms the presence of Leishmania major in the Americas

Leishmania (Leishmania) major is an important agent of cutaneous leishmaniasis, having as a vector sandflies belonging to the genus Phlebotomus. Although this species has been described as restricted to the Old World, parasites similar to L. major have been isolated from South American patients who have never travelled abroad. These parasites were named “L. major-like”, and several studies have been carried out to characterise them biochemically, molecularly, and biologically. However, the phylogenetic origin of these isolates is still unknown. In the present study we characterised three L. major-like isolates, named BH49, BH121 and BH129, using comparative genomics approaches. We evaluated the presence of gene and segmental duplications/deletions and the presence of aneuploidies that could explain the differences in infectivity observed in the BH49 and BH121 isolates. All isolates presented a pattern of mosaic aneuploidy and gene copy number variation, which are common in the genus Leishmania. Virulence factors such as phosphatases and peptidases were found to have increased gene copy numbers in the infective isolate, which could explain the difference in infectivity previously observed between BH121 and BH49. Phylogenetic analyses revealed that BH49, BH121 and BH129 L. major-like grouped with L. major isolates, and suggest they were imported from the Old World in at least two independent events. We suggest that new epidemiological inquiries should also evaluate L. major infections in South America, to assess the epidemiological importance of this species in the New World.     

Utility of arginine kinase for resolution of phylogenetic relationships among Brachyuran genera and families

The molecular phylogenetics of decapod crustaceans has been based on sequence data from a limited number of genes. These have included rapidly evolving mitochondrial genes, which are most appropriate for studies of closely related species, and slowly evolving nuclear ribosomal RNA genes, which have been most useful for resolution of deep branches within the Decapoda. Here we examine the utility of the nuclear gene that encodes arginine kinase for phylogenetic reconstruction at intermediate levels (relationships among genera and families) within the decapod infraorder Brachyura (the true crabs). Analyses based on arginine kinase sequences were compared and combined with those for the mitochondrial cytochrome oxidase I gene. All of the genera in our taxon sample were resolved with high support with arginine kinase data alone. However, some of these genera were grouped into clades that are in conflict with recognized brachyuran families. A phylogeny based on cytochrome oxidase I was consistent with the arginine kinase phylogeny, but with weaker support. A recently proposed measure of phylogenetic informativeness indicated that arginine kinase was generally more informative than cytochrome oxidase I for relationships above the level of genus. Combined analysis of data from both genes provided strong support for clades that are in conflict with current assignments of genera to the families Epialtidae, Mithracidae, Pisidae, and Portunidae.     

Chromosome numbers of some caespitose bamboos native in or introduced to China

This paper reports chromosome numbers of 94 species in 13 genera of caespitose bamboos native in or introduced to China. The chromosome numbers of 74 species are roported here for the first time. The original basic number of bamboos is considered to be x = 8. Chromosome numbers ofmost of the caespitose bamboos are found to be 2n = 70 ± 2.     

中国部分丛生竹类染色体数目报道

本文报道了我国13属94种丛生竹类的染色体数目。其中21种已见报道,74种为首次报道。作者推测竹类染色体原始基数可能为x=8。多数丛生竹类染色体数目为2n=70±2。     

Phylogenetic analysis of the genera Planococcus, Marinococcus and Sporosarcina and their relationships to members of the genus Bacillus

A phylogenetic analysis based on 16S rRNA was performed on the genera Planococcus, Marinococcus, Sporosarcina and endospore-forming rods. In agreement with earlier 16S rRNA cataloguing data, Planococcus citreus and Sporosarcina ureae clustered with Bacillus pasteurii and other bacilli containing lysine in their cell walls. Sporosarcina halophila was shown to be genetically distinct from S. ureae and formed a loose association with the main Bacillus subtilis grouping. Marinococcus halophilus (formerly Planococcus halophilus) exhibited low levels of relatedness to all reference species examined and formed a distinct line of descent.     

Phylogenetic relationships of four endemic genera of the Phasianidae in China based on mitochondrial DNA control-region genes

The taxonomic status of some genera within the Phasianidae remains controversial. To demonstrate the phylogenetic relationships of four endemic genera (Tetraophasis, Ithaginis, Crossoptilon and Chrysolophus) and other 11 genera of Phasianidae in China, a total of 1070 nucleotides of mitochondrial DNA (mtDNA) control-region genes were sequenced. There are 376 variable sites including 345 parsimony sites. The genetic distance ranged from 0.067 (Chrysolophus and Phasianus) to 0.181 (Perdix and Bambusicola) among the 15 genera. Maximum likelihood method was used to construct a phylogenetic tree, which grouped all the genera into two deeply divergent clades. Perdix was shown to be a non-partridge genus. Alternatively, it appears ancestral to either partridges or pheasants. The sibling taxa of the four endemic genera were Lophophorus, Tragopan, Lophura and Phasianus, respectively. Calibrated rates of molecular evolution suggested that the divergence time between the four genera and related taxa was 4.00–5.00 million years ago, corresponding to the Pliocene. Considering their molecular phylogenetics, fossil and geographical distribution patterns, the four endemic genera might have originated in the southwestern mountains in China.