Rapid and parallel chromosomal number reductions in muntjac deer inferred from mitochondrial DNA phylogeny

Muntjac deer (Muntiacinae, Cervidae) are of great interest in evolutionary studies because of their dramatic chromosome variations and recent discoveries of several new species. In this paper, we analyze the evolution of karyotypes of muntjac deer in the context of a phylogeny which is based on 1,844-bp mitochondrial DNA sequences of seven generally recognized species in the muntjac subfamily. The phylogenetic results support the hypothesis that karyotypic evolution in muntjac deer has proceeded via reduction in diploid number. However, the reduction in number is not always linear, i.e., not strictly following the order: 46-->14/13-->8/9-->6/7. For example, Muntiacus muntjak (2n = 6/7) shares a common ancestor with Muntiacus feae (2n = 13/14), which indicates that its karyotype was derived in parallel with M. feae's from an ancestral karyotype of 2n greater than or equal to 13/14. The newly discovered giant muntjac (Muntiacus vuquangensis) may represent another pa;allel reduction lineage from the ancestral 2n = 46 karyotype. Our phylogenetic results indicate that the giant muntjac is relatively closer to Muntiacus reevesi than to other muntjacs and may be placed in the genus Muntiacus. Analyses of sequence divergence reveal that the rate of change in chromosome number in muntjac deer is one of the fastest in vertebrates. Within the muntjac subfamily, the fastest evolutionary rate is found in the Fea's lineage, in which two species with different karyotypes diverged in around 0.5 Myr.

中国华中铁角蕨复合体和铁角蕨复合体几个种的生物系统学研究

本文综合形态学、孢粉学和细胞学以及等位酶分析的实验证据，阐明了中国华中铁角蕨复合体（Asplenium sarelii Hook. Complex）中两个四倍体种的起源问题，并从生物系统学的角度讨论了其中多个种的分类学问题。过去认为的四倍体的“华中铁角蕨”被证明是起源于二倍体华中铁角蕨（A. sarelii Hook.）和二倍体细茎铁角蕨（A. tenuicaule Hayata）的杂交，并被处理为新种：武当铁角蕨（A. wudangense Z.R. Wang et X. Hou, sp. nov.）。 而变异铁角蕨（A. varians Wall., Hook. et Grev.）则被认为起源于二倍体细茎铁角蕨（A. tenuicaule Hayata）和二倍体尖齿铁角蕨（A. argutum Ching）的杂交或二者同源四倍体的杂交。根据原细茎铁角蕨（A. tenuicaule Hayata）和尖齿铁角蕨（A. argutum Ching）在宏观和微观特征上的相似性，以及二者的遗传一致度（0.581～0.705），本文将这两个种处理为细茎铁角蕨（A. tenuicaule Hayata）的两个亚种：细茎亚种(ssp. tenuicaule）和尖齿亚种（ssp. argutum （Ching） Vaine, Rashbach et Reichst., ined.）。依据形态和遗传上的相似性以及各自占有一定部分重叠的分布区域，原云南铁角蕨（A. yunnanense Franch.）、宝兴铁角蕨（A. moupinense Franch.）和云南铁角蕨深裂铁角蕨变种（A. yunnanense Franch. var daraeiforme（Franch.）H. S. Kung）被处理为云南铁角蕨（A. yunnanense Franch.）的三个亚种：云南铁角蕨亚种（ssp. yunnanense）、宝兴铁角蕨亚种（ssp. moupinense （Franch.）Z. R. Wang et X. Hou, st. nov.）和深裂铁角蕨亚种（ssp. daraeiforme（Franch.）Z. R. Wang et X. Hou, st. nov.）。 同时，本文运用孢粉学、细胞学、生态学和形态学的综合手段，处理了中国铁角蕨（Asplenium trichomanes L. s. l.）的种下分类问题，划分了中国该种的四个亚种：原亚种A. trichomanes L. ssp. trichomanes，喜钙亚种A. trichomanes L. ssp. inexpectans Lovis，四倍亚种A. trichomanes L. ssp. quadrivalens D. E. Meyer emend. Lovis，粗轴亚种A. trichomanes L. ssp. pachyrachis （Christ） Lovis et Reichst.，并将一个变种：哈如变种A. trichomanes L. var. harovii Moore emend. Midle，归并入粗轴亚种ssp. pachyrahcis (Christ) Lovis et Reichst.，同时提供了它们在中国的分布情况。查阅研究PE的标本时发现一些定名为为A. trichomanes L. var. centrochinense Christ（中国变种）的模式标本碎片，因在形态上和倍性上均不同于已知分类群，认为应给予种的分类地位。

丁香属（Syringa L.）的分类学修订

丁香属隶属于木犀科，分布于东南欧和东亚至喜马拉雅地区，我国是丁香属的现代分布中心。《中国植物志》（61卷，1992）记录了我国野生丁香种类16种;《Flora of China》（15卷，1996）记录了中国原产丁香种类16种，并认为全世界大约有20种。丁香属属下分类等级划分分歧较大，很多种的划分也存在争议。花叶丁香、四川丁香等种类是根据栽培植物描述的，没有指定模式标本，给分类处理带来了一定困难。另外，丁香属很多分类群的性状变异非常复杂，仅根据有限的标本很难做出合理的分类处理。本研究通过广泛查阅文献和标本，同时进行野外居群取样和性状观察，对各类群的性状在居群内和居群间的变异进行统计学分析，判断其分类价值，并运用多变量分析的方法，为各类群的合理划分提供依据。结合性状分析和地理分布等证据，做出分类处理。 作者查阅了国内外16个标本馆的近2000份标本，其中模式标本约70份。对我国12个省市的40余个居群进行了取样和观察，采集标本500余份，涉及了《中国植物志》61卷收录的除了藏南丁香以外的所有类群。通过对9个复合体的40余个性状在居群内和居群间的变异进行统计分析，发现叶片类型、叶柄长度、花序着生类型、花冠大小、花丝长度、花药颜色在不同类群间差异明显，可以用作划分种的依据;叶片形状、叶片毛被、花序轴毛被、花冠管形状等性状在有些复合体内的居群间呈现连续的变异，只能用作种下等级（亚种）的划分;叶片大小、花序轴形状、花药着生在花冠的位置、蒴果是否被皮孔等性状在不同复合体的居群间呈现间断或连续的变异，视不同情况可以用作种间或种下等级的划分依据，或作种内变异处理;而叶脉、花色、花萼齿裂、花冠裂片形状等性状在居群间差异不大，不适合用作分类依据。 在性状分析和多变量分析的基础上，本文将丁香属划分为2组2系12种13亚种，其中短花冠管组有1种3亚种;长花冠管组的顶生花序系有5种5亚种，侧生花序系有6种5亚种，并指定了各组和系的模式种;编制了属下各组、系、种和亚种划分的检索表，对12种13亚种进行了形态描述、标本引证，给出了地理分布图和生境，并提出了分类处理依据。文中对巧玲花、皱叶丁香、红丁香和云南丁香等复合体内的一些分类群进行了归并，做出4个新组合：S. pubescens ‘Meyer’、S. villosa subsp. wolfii、S. yunnanensis subsp. sweginzowii和S. yunnanensis subsp. tomentella，处理了11个新异名（S. fauriei H. Lév.、S. julianae C. K. Schneid.、S. meyeri var. spontanea M. C. Chang、S. pinetorum W. W. Sm.、S. wardii W. W. Sm.、S. oblata var. donaldii R. B. Clark et J. L. Fiala、S. afghanica C. K. Schneid.、S. protolaciniata P. S. Green et M. C. Chang、S. tibetica P. Y. Bai、S. reflexa C. K. Schneid. 、S. wilsonii C. K. Schneid.）。作者指定了3种4亚种(S. reticulata subsp. reticulata、 S. reticulata subsp. amurensis、S. pubescens subsp. microphylla、S. oblata subsp. dilatata的后选模式，并对其它10个名称指定了后选模式。文中还提出了分类处理原则，对我国丁 香属的分布及各地方植物志的记载进行了评述，并对丁香属的分布格局提出了作者的看法。 作者还对13个分类群的16号材料进行了染色体观察，发现除了毛丁香有染色体2n=48外，其它均为2n=46，其中朝阳丁香的染色体数目为首次报道。对小叶巧玲花不同异名（包括小叶蓝丁香、小叶巧玲花与小叶蓝丁香的杂交种）的材料进行染色体观察时，发现它们之间差异很小，进一步佐证了作者将其合并的合理性。另外野生的花叶丁香（华丁香）与栽培的花叶丁香在染色体数目上也无差异，支持了作者认为二者为同物异名的观点。

ACHT操作引起黑麦(Secale cereale)染色体的畸变和重建

用ACHT处理黑麦萌动种子，对修复前后材料的观察和分析结果表明：1. ACHT操作引起染色体数目变化和染色体断裂损失。在一定 条件和范围内，不同处理引起的这种变化具有显著差异，条件越剧烈，染色体数目变化的范围和频率愈大，断片发生的数量和频率 也愈高，同时修复前后染色体数目的变化范围和频率与断片发生的数量和频率以及它们的修复频率均表现明显的相关性。2. ACHT 操作引起染色体畸变的多样性。经ACHT处理后，胚根细胞染色体有4种断裂方式，包括着丝粒断裂、次溢痕断裂、长臂断裂和短臂 断裂等，其中着丝断裂频率最高；产生6种断片类型，包括有着丝粒和端粒的、有着丝粒而无端粒的、有部分着丝粒和端粒的、有 部分着丝粒而无端粒的、只有端粒的、既无着丝粒也无端粒的断片等。3. ACHT操作引起遗传结构重建的多样性。经ACHT处理后， 对修复24-72小时材料进行核型比较(按Stebbins 和 Levan 标准)和随体分析，处理细胞在染色体数目、大小、形态、位置等方面 均发生显著变化，说明ACHT处理使这些细胞的染色体结构和染色体组型发生了深刻变化。进一步通过Giemsa C— 带分析，观察到 多种重建染色体类型，包括易位型染色体、附加型染色体、无着丝粒染色体、化染色体、增加的m染色体以及某些带型特异的染色 体等。4. RAPD 分析从分子水平上验证了ACHT能有效地引起遗传结构的改变。所用10种引物对处理和对照材料基因组DNA的扩增产 物在条带数目、条带位置及带型特征等方面均有明显差异，其中4种引物出现条带减少，6种引物出现条带增加，后者还包括一个带 位移动。这说明两种材料的基因组DNA具有明显的RAPD反应多态性差异。This paper descripes some results draw on the basis of the observation and analysis on the rye before and after repaired through treating its budding seeds by ACHT in contrast to without ACHT: 1. ACHT manipulation caused the number variation and breakage damage of rye chromosome. Within certain conditions and timits, this phenomenon caused by different treats had signifcant difference: the more the treatment condition is drastie, the more the chageable range and frequence of rye chromosomae number, and so is the produced fragments. Meanwhile, there existed striking relationship among the changeable range and frequence of rye chromosome, the produced number and frequence of fragments and repairing frequence. 2. ACHT manipulafion engendered the diversify of rye chromosomal aberration. Four breakage patterns and six sorts of fragment were observed by watching the chromosome of the rye radicle treated by ACHT, including centric breakage (occuring in the highest frequence), secondary constriction breakage, long arm breakage and short arm breakage to the former, Comprising that with both centromere and telomere, that with centromere and without telomere, that with partial centromere and with telomere, that with partfial ceetromere and without telomere, that only with telomere and that neither with centromere nor with telomere, etc. 3. ACHT manipulation engendered the diversify or rye genetic structs reconstruction. Karureotype analysis(according to Stebbins and Levan) and satellite anaeysis were carried out to rye radicle through 24-72-hour-long recoverage after ACHT manipulation, which showed remarkable change happened on the rye chromosomal number、shape、arm ration and pattern, etc. and also on the satellite number、size、shape and location etc. Those indicated that ACHT manipulation engendered violent changes to rye chromatin structure and chromosome type. Further Giemsa C-banding analysis showed many types of reconstructed chromosome, such as translocation、addition、without centromere、st and other chromosome. 4. RAPD analysis checked the validity of ACHT on changing genetic structure of rye on the level of molecular biology. The treated and recovered rye has different amplifying band pattern by using IO valid arbitary primers selected from 40 comparing with the control.

Chromosomal rearrangements underlying karyotype differences between Chinese pangolin (Manis pentadactyla) and Malayan pangolin (Manis javanica) revealed by chromosome painting

The Chinese pangolin (Manis pentadactyla), a representative species of the order Pholidota, has been enlisted in the mammalian whole-genome sequencing project mainly because of its phylogenetic importance. Previous studies showed that the diploid number o

Construction, characterization and chromosomal mapping of bacterial artificial chromosome (BAC) library of Yunnan snub-nosed monkey (Rhinopithecus bieti)

We constructed a high redundancy bacterial artificial chromosome library of a seriously endangered Old World Monkey, the Yunnan snub-nosed monkey (Rhinopithecus bieti) from China. This library contains a total of 136 320 BAC clones. The average insert size of BAC clones was estimated to be 148 kb. The percentage of small inserts (50-100 kb) is 2.74%, and only 2.67% non-recombinant clones were observed. Assuming a similar genome size with closely related primate species, the Yunnan snub-nosed monkey BAC library has at least six times the genome coverage. By end sequencing of randomly selected BAC clones, we generated 201 sequence tags for the library. A total of 139 end-sequenced BAC clones were mapped onto the chromosomes of Yunnan snub-nosed monkey by fluorescence in-situ hybridization, demonstrating a high degree of synteny conservation between humans and Yunnan snub-nosed monkeys. Blast search against human genome showed a good correlation between the number of hit clones and the size of the chromosomes, an indication of unbiased chromosomal distribution of the BAC library. This library and the mapped BAC clones will serve as a valuable resource in comparative genomics studies and large-scale genome sequencing of nonhuman primates. The DNA sequence data reported in this paper were deposited in GenBank and assigned the accession number CG891489-CG891703.

Chromosomal rearrangement in Pectinidae revealed by rRNA loci and implications for bivalve evolution

Karyotype and chromosomal localization of major (18-5.8-28S) and minor (5S) ribosomal RNA genes were studied in two species of Pectinidae, zhikong (Chlamys farreri) and bay (Argopecten irradians irradians) scallops. using fluorescence in situ hybridization (FISH). C. farreri had a haploid number of 19 with a karyotype of 3m + 4sm + 7sm-st + 4st + 1st-t, and A. i. irradians had a haploid number of 16 with a karyotype of 5st + 11t. In C. farreri, the major and minor rRNA genes had one locus each and were mapped to the same chromosome-Chromosome 5. In A. i. irradians, the major rRNA genes had two loci, located on Chromosomes 4 and 8, and the 5S rRNA gene was found at a third chromosome-Chromosome 10. Results of this and other studies indicate that karyotype of A. i. irradians (n = 16, 21 arms) is secondary and derived from an ancestral karyotype similar to that of C. farreri (n = 19, 38 arms) through considerable chromosomal loss and rearrangements. The ability to tolerate significant chromosomal loss suggests that the modal karyotype of Pectinidae and possibly other bivalves with a haploid number of 19 is likely tetraploid; i.e., at least one genome duplication has occurred during the evolution of Bivalvia.

Chromosomal mapping of major ribosomal rRNA genes in the hard clam (Mercenaria mercenaria) using fluorescence in situ hybridization

Karyotype and chromosomal location of the major ribosomal RNA genes were studied in the hard clam (Mercenaria mercenaria Linnaeus) using fluorescence in situ hybridization (FISH). Metaphase chromosomes were obtained from early embryos. Internal transcribed spacers (ITS) between major RNA genes were amplified and used as FISH probes. The probes were labeled with digoxigenin-11-dUTP by polymerase chain reaction and detected with fluorescein-labeled anti-digoxigenin antibodies. FISH with the ITS probes produced two to four signals per nucleus or metaphase. M. mercenaria had a haploid number of 19 chromosomes with a karyotype of seven metacentric, four metacentric or submetacentric, seven submetacentric, and one submetacentric or subtelocentric chromosomes (7M + 4M/SM + 7SM + 1SM/ST). Two ITS loci were observed: one located near the centromere on the long arm of Chromosome 10 and the other at the telomere of the short arm of Chromosome 12. FISH signals on Chromosome 10 are strong and consistent, while signals on Chromosome 12 are variable. This study provides the first karyotype and chromosomal assignment of the major RNA genes in M. mercenaria. Similar studies in a wide range of species are needed to understand the role of chromosomal changes in bivalve evolution.

Chromosomal mapping of the major ribosomal RNA genes in the dwarf surfclam (Mulinia lateralis Say)

Chromosomal location of the major ribosomal RNA genes (rRNA) were studied in the dwarf surfclam (Mulinia lateralis, Say) using fluorescence in situ hybridization (FISH). FISH probes for the rRNA genes were made by polymerase chain reaction (PCR), labeled with digoxigenin-11-dUTP and detected with fluorescein-labeled antidigoxigenin antibodies. Mulinia lateralis had a diploid number of 38 chromosomes and all chromosomes were telocentric. FISH with the rRNA probe produced positive and consistent signals on two pairs of chromosomes: Chromosome 15 with a relative length of 4.6% and Chromosome 19, the shortest chromosome. Both loci were telomeric. The rRNA location provides the first physical landmark of the M. lateralis genome.

Telomerase Activity and Microgravity-Dependent Apoptosis in Human Leukemia HL-60 Cells

Mammalian cells subjected to conditions of spaceflight and the microgravity environment ofspace; manifest a number of alterations in structure and function. Among the most notable changes incells flown on the Space Shuttle are reduced growth activation and decline in growth rate in the totalpopulation. Other changes include chromosomal aberrations, inhibited locomotion, alteredcytokine production, changes in PKC distribution, and increased apoptos.

An analysis on overall crack-number-density of short-fatigue-cracks

The evolution of dispersed short-fatigue-cracks is analysed based on the equilibrium of crack-number-density (CND). By separating the mean value and the stochastic fluctuation of local CND, the equilibrium equation of overall CND is derived. Comparing with the mean-field equilibrium equation, the equilibrium equation of overall CND has different forms in the expression of crack-nucleation-rate or crack-growth-rate. The simulation results are compared with experimental measurements showing the stochastic analyses provide consistent tendency with experiments. The discrepancy in simulation results between overall CND and mean-field CND is discussed.

Generalization of Response Number for Dynamic Plastic Response of Shells Subjected to impulsive Loading

A dimensionless number, termed as response number in Zhao [Archive of Applied Mechanics 68 (1998) 524], has been suggested for the dynamic plastic response of beams and plates made up of rigidly perfect plastic materials subjected to dynamic loading. Many theoretical and experimental results can be reformulated into new concise forms with the response number. The concept of a new dimensionless number, response number, termed as Rn(n), is generalized in Zhao [Forschung im Ingenieurwesen 65 (1999) 107] to study the elastic, plastic, dynamic elastic as well as dynamic plastic buckling problems of columns, plates as well as shells. The response number Rn(n) is generalized to the dynamic behaviour of shells of various shapes in the present paper.

Application of response number for dynamic plastic response of plates subjected to impulsive loading

A dimensionless number, termed response number, is applied to the dynamic plastic response of plates subjected to dynamic loading. Many theoretical and experimental results presented by different researchers are reformulated into new concise forms with the response number. The advantage of the new forms is twofold: (1) they are more physically meaningful, and (2) they are independent of the choice of units, thus, they have wider range of applications.

Effect of liquid bridge volume on the instability in small-Prandtl-number half zones

A perturbation method is used to examine the linear instability of thermocapillary convection in a liquid bridge of floating half-zone filled with a small Prandtl number fluid. The influence of liquid bridge volume on critical Marangoni number and flow features is analyzed. The neutral modes show that the instability is mainly caused by the bulk flow that is driven by the nonuniform thermocapillary forces acting on the free surface. The hydrodynamic instability is dominant in the case of small Prandtl number fluid and the first instability mode is a stationary bifurcation. The azimuthal wave number for the most dangerous mode depends on the liquid bridge volume, and is not always two as in the case of a cylindrical liquid bridge with aspect ratio near 0.6. Its value may be equal to unity when the liquid bridge is relatively slender.

Optimized Group Velocity Control Scheme and DNS of Decaying Compressible Turbulence of Relative High Turbulent Mach Number

To overcome the difficulty in the DNS of compressible turbulence at high turbulent Mach number, a new difference scheme called GVC8 is developed. We have succeeded in the direct numerical simulation of decaying compressible turbulence up to turbulent Mach number 0.95. The statistical quantities thus obtained at lower turbulent Mach number agree well with those from previous authors with the same initial conditions, but they are limited to simulate at lower turbulent Mach numbers due to the so-called start-up problem. The energy spectrum and coherent structure of compressible turbulent flow are analysed. The scaling law of compressible turbulence is studied. The computed results indicate that the extended self-similarity holds in decaying compressible turbulence despite the occurrence of shocklets, and compressibility has little effects on relative scaling exponents when turbulent Mach number is not very high.