Molecular phylogeny and inflorescence evolution of Prunus(Rosaceae)based on RAD-seq and genome skimming analyses

Prunus is an economically important genus widely distributed in the temperate Northern Hemisphere.Previous studies on the genus using a variety of loci yielded conflicting phylogenetic hypotheses.Here,we generated nuclear reduced representation sequencing data and plastid genomes for 36 Prunus individuals and two outgroups.Both nuclear and plastome data recovered a well-resolved phylogeny.The species were divided into three main clades corresponding to their inflorescence types,-the racemose group,the solitary-flower group and the corymbose group-with the latter two sister to one another.Prunus was inferred to have diversified initially in the Late Cretaceous around 67.32 million years ago.The diversification of the three major clades began between the Paleocene and Miocene,suggesting that paleoclimatic events were an important driving force for Prunus diversification.Ancestral state reconstructions revealed that the most recent common ancestor of Prunus had racemose inflorescences,and the solitary-flower and corymb inflorescence types were derived by reduction of flower number and suppression of the rachis,respectively.We also tested the hybrid origin hypothesis of the racemose group proposed in previous studies.Prunus has undergone extensive hybridization events,although it is difficult to identify conclusively specific instances of hybridization when using SNP data,especially deep in the phylogeny.Our study provides well-resolved nuclear and plastid phylogenies of Prunus,reveals substantial cytonuclear discord at shallow scales,and sheds new light on inflorescence evolution in this economically important lineage.

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.

Evolutionary relationships of mitogenomes in a recently radiated Old World avian family

Environmentally heterogeneous mountains provide opportunities for rapid diversification and speciation.The family Prunellidae(accentors)is a group of birds comprising primarily mountain specialists that have recently radiated across the Palearctic region.This rapid diversification poses challenges to resolving their phylogeny.Herein we sequenced the complete mitogenomes and estimated the phylogeny using all 12(including 28 individuals)currently recognized species of Prunellidae.We reconstructed the mitochondrial genome phylogeny using 13 protein-coding genes of 12 species and 2 Eurasian Tree Sparrows(Passer montanus).Phylogenetic relationships were estimated using a suite of analyses:maximum likelihood,maximum parsimony and the coalescent-based SVDquartets.Divergence times were estimated by implementing a Bayesian relaxed clock model in BEAST2.Based on the BEAST time-calibrated tree,we implemented an ancestral area reconstruction using RASP v.4.3.Our phylogenies based on the maximum likelihood,maximum parsimony and SVDquartets approaches support a clade of large-sized accentors(subgenus Laiscopus)to be sister to all other accentors with small size(subgenus Prunella).In addition,the trees also support the sister relationship of P.immaculata and P.rubeculoides+P.atrogularis with 100%bootstrap support,but the relationships among the remaining eight species in the Prunella clade are poorly resolved.These species cluster in different positions in the three phylogenetic trees and the nodes are often poorly supported.The five nodes separating the seven species diverged simultaneously within less than half million years(i.e.,between 2.71 and 3.15 million years ago),suggesting that the recent radiation is likely responsible for rampant incomplete lineage sorting and gene tree conflicts.Ancestral area reconstruction indicates a central Palearctic region origin for Prunellidae.Our study highlights that whole mitochondrial genome phylogeny can resolve major lineages within Prunellidae but is not sufficient to fully resolve the relationship among the species in the Prunella clade that almost simultaneously diversify during a short time period.Our results emphasize the challenge to reconstruct reliable phylogenetic relationship in a group of recently radiated species.

北京大学燕园鸟类组成

2003—2012年,在北京大学燕园校区进行鸟类调查446次。其中2010—2012年,春季、秋季每周平均两次,夏季、冬季每周平均一次,总计234次,468小时。共记录鸟类178种,隶属14目37科102属,其中留鸟24种,旅鸟117种,夏候鸟24种,冬候鸟19种,迷鸟1种。其中有国家I级重点保护鸟类1种,国家Ⅱ级重点保护鸟类20种,水鸟28种。燕园各区域中,静园鸟种最少,仅记录28种。鸣鹤园鸟种最多,记录109种。在鸣鹤园和镜春园,迂回水道与覆盖有天然次生林的土丘交错,有73种鸟仅记录于上述地点。燕园各区域的次生林和人工绿地比例是影响鸟类多寡的关键因素。

中国北方主要坚果类淀粉粒形态对比

近年，考古学家发现坚果类植物在农业起源中曾占有很重要的地位。为了对考占器物上附着的淀粉粒进行鉴定，我们对中国北方现代主要坚果类栗属（Castanea）中的板栗（C．mollisima）、栎属（Quercus）中的槲树（p．dentata）、槲栎（Q．aliena）、麻栎（Q．acutissima）、栓皮栎（p．viriabilis）、蒙古栎（Q．mongolicus）和胡桃属（Juglans）中的胡桃楸（J．mandshurica）共7个样品进行了淀粉粒形态对比分析，以求为建立北方坚果类淀粉粒的鉴定标准积累资料。实验结果发现，除胡桃楸未发现淀粉物质以外，其他6个样品的淀粉粒不仅可以与其他科、属进行区分，甚至在一定程度上还可以进行种问的区分。板栗的脐点是闭合的，有层纹，无裂隙；麻栎脐点是偏心的；槲树栓皮栎的淀粉粒近乎80％都具有裂隙特征，但栓皮栎的淀粉粒中会出现横裂隙和相当数量的星形裂隙而只有槲树的淀粉粒才具有相当数量的纵向裂隙；蒙古栎的淀粉也大多具有裂隙（〉70％）而且纵向型裂隙占主要地位，但是蒙古栎淀粉粒表面有细密的放射线；60％的槲栎淀粉粒不具有裂隙特征。所有样品的淀粉粒均由大小不一的各种卵圆形组成，而且6个样品的长轴最大值（约20μm）和6个样品的平均值（约10μm）都非常接近。

裸子植物雄球花——纤细堆囊穗的修订(英文)

研究了采自中国东北晚三叠世羊草沟组的一种裸子植物雄球花——纤细堆囊穗。通过对新材料的研究,发现这种雄球花小孢子叶末端的裂片在形态上差异很大,这是原来没有发现的十分重要的特征。这些保存精美的化石对于纤细堆囊穗特征的阐明和修订以及物种复原很有帮助。将中国的标本与西伯利亚堆囊穗、小堆囊穗、乌尔马堆囊穗和被定为长叶拜拉的雄球花进行了比较,发现它们与纤细堆囊穗在特征上一致,故将它们处理为纤细堆囊穗的异名。修订后的纤细堆囊穗包括上面所提到的所有种。同时,也讨论了堆囊穗属可能的演化意义。它可能是银杏属的远祖,经过小孢子囊数目的减少和小孢子叶长度的缩短而演化到现在的银杏,而产自辽西早白垩世的辽宁银杏可能代表了堆囊穗和现代银杏在形态演化上的一个中间步骤。

东南亚地区五加科植物进化关系的初步研究(英文)

东南亚五加科包含14个属约500种,本文应用ITS片段对该区五加科植物的进化关系作了初步研究。研究显示该地区五加科植物具有复杂的起源,很多属属于亚洲掌状复叶类群或Hedereae族的一支中。该区特有类群Harmsiopanax形态上非常特殊,但其系统位置尚未不明朗。在Brassaiopsis属中,有几种形态差异较大的种,但它们属同一单系,加之各种间ITS序列差异较小,故应是新近起源于马来亚半岛和苏门达腊岛的种类。Wardenia simplex聚类在Brassaiopsis一支中,故不支持将Wardenia作为独立的属。东南亚地区对于Schefflera属的发育非常重要,已有的证据显示该区的Schefflera属植物属于该属的Heptapleurum类群。马来亚与泰国南部的Dendropanax lancifolius并没有与Dendropanax属的核心类群聚在一起,其系统地位需进一步研究。Macropanax maingayi是非常特殊的一个种,曾被独立分出,成立了单种属Hederopsis。本文的分析清楚表明它属于Macropanax属。Aralia merrillii因为其不同寻常的攀缘特性而被独立出来,建立了单种属Acanthophora,但ITS序列分析支持将它置于Aralia属中。新增的取样继续支持Arthrophyllum的单系性。Os-moxylon的原初分布范围在东南亚,它是五加科系统进化树上孤立的类群。

中国忍冬科分布新记录——温州六道木(英文)

温州六道木AbeliaspathulataSieb.&Zucc.原来被认为特产于日本,最近发现也分布在我国浙江省永嘉县四海山。温州六道木与糯米条A.chinensisR.Brown的亲缘关系最近,但温州六道木聚伞花序仅2花,生于小枝顶端;花冠白色或粉红色,长2–3cm,钟状,裂片二唇形;雄蕊不伸出花冠筒外。糯米条聚伞花序多花,集生于小枝顶部叶腋成圆锥花序状;花冠白色,长0.5–1cm,漏斗状,裂片近辐射对称;雄蕊显著伸出花冠筒外。

适应辐射类群穇属的系统学研究进展

综合花序拓扑学、比较形态学、分子系统发育、细胞遗传学等资料,对适应辐射类群穇属(Eleusine Gaertn.)的系统学研究进展进行了述评。穇属系统位置——Eleusiinae亚族成员得到分子系统发育证据的支持。该属具有3种花序类型、7个基因组类型、多倍体均由二倍体杂交起源、C4植物高度适应半湿润-半干旱镶嵌气候等特征。据可靠化石记载和现代地理分布推断,穇属很可能起源于东非,时间是晚中新世,而适应辐射则发生在上新世-中新世间隔。总的来说,分子系统发育、细胞遗传学、古地质、古气候数据的整合研究能够为穇属多倍体起源和谱系多样化历史提供令人信服的证据。

人类最早出现在东北亚高纬度地区的新证据

确定早期人类扩散到亚洲的时间是人类演化研究的中心课题之一。在华北泥河湾盆地马圈沟湖相沉积剖面发掘出四层无可争议的石器层。本项研究的磁性地层学结果表明，这四层石器层的年龄介于Olduvai极性亚时和Cobb Mountain事件之间的近34万年时间间隔内。层位最低的旧石器的年龄约1．66Myr，代表了东亚地区利用石器加工动物遗骨最古老的记录。

人类在东北亚的最早出现

在人类演化研究中，不同地区早期人类及石器技术的年代问题一直是争论的焦点。对华北泥河湾翁地的小长梁和洞沟这两个平行的湖相沉积剖面作了洋细的磁性地层学研究，为20多年前在这里发现的旧石器进行了精确定年。古地磁结果表明，小长梁行器层位于奥杜韦和哈拉米洛两个正极性亚时之间的负极性带内。假定这一负极性带形成时间段内的沉积速率恒定，那么小长梁石器层的形成年龄大约是距今1．36Myr。这一结果是东亚高纬度地区（40°N）古人类活动的最早证据。

中国青铜技术研究回顾与展望

目前，中国青铜技术研究领域相当活跃，不断出现的考古新发现展示了过去一无所知的中国古代科技成就，亚洲各地及西方的最新研究又使人们对中国古代科技有了更深刻的认识。夏、商、周三代以及秦、汉两代的研究较为深入，汉之后的青铜技术研究看来还只是刚刚开始。

穇属颖果微形态及其系统学意义

在电子扫描显微镜下观察了穇属(Eleusine Gaertn.)9种植物颖果的微形态特征。结果表明,穇属颖果有卵形、披针形和矩圆形3种腹面形状,压扁方式有背腹压扁及两侧压扁,腹面形态有平腹面和凹腹面两种,胚比为0.29～0.58,种脐比为0.10～0.24,颖果纹饰有2种,包括疣突状一级纹饰和疣突规则排列构成的复合网状(二级)纹饰,表面小孔平均直径0.57～1.31μm,分布密度为30～200个(100μm-2)。穇属植物的颖果腹面形状、纹饰、表面小孔直径及平均密度等性状,可为种类鉴定及种间关系分析提供有价值的证据。穇属颖果腹面形态呈平腹面或凹腹面,颖果体积相对小,生活周期相对缩短,这可能是与东非季节性干旱气候相适应的。

New Jurassic Pseudopolycentropodids from China (Insecta: Mecoptera)

In this paper two new species of fossil Pseudopolycentropus Handlirsch, 1906 are described： Pseudopolycentropus janeannae sp. nov. and P. novokshonovi, sp. nov. All of them were recovered from the Middle Jurassic non-marine sedimentary strata of northeastern China. The new material from China reveals that the early diversification of pseudopolycentropodids was well underway by the Middle Jurassic.

New Mesozoic Mesopsychidae (Mecoptera) from Northeastern China

The Mesozoic family Mesopsychidae Tillyard, 1917 presently consists of seven described genera and 13 species from the mid-Triassic to the Early Cretaceous of Australia, South Africa and Eurasia. In the present paper one new genus and three new species of fossil mesopsychids are described that add significant distributional and stratigraphic extensions to the family. This finding documents the first formal record of fossil Mesopsychidae in China. Both Lichnomesopsyche gloriae gen. et sp. nov. and L. daohugouensis gen. et sp. nov. were found from the Middle Jurassic Jiulongshan Formation of Inner Mongolia, whereas Vitimopsyche kozlovi sp. nov., of mid Early Cretaceous age, was collected from the Jehol Biota of northern Hebei Province. This new, wellpreserved material from China reveals complete and previously unknown body features, including head, antennae, mouthparts, legs and abdomen. The delicate and long proboscides of these new taxa indicate that they were feeding on externally exposed, nutrient-rich fluids of gymnospermous ovulate fructifications, and incapable of piercing surface epidermis - attributable principally to the absence of stylets. These proboscides originated, perhaps multiply, among basal Mecoptera and are functionally and structurally convergent with equivalent mouthparts borne by fossil and extant Diptera, Lepidoptera, Neuroptera and Coleoptera.

Evolution of the Madrean-Tethyan disjunctions and the North and South American amphitropical disjunctions in plants

The present paper reviews advances in the study of two major intercontinental disjunct biogeographic patterns： （i） between Eurasian and western North American deserts with the Mediterranean climate （the Madrean- Tethyan disjunctions）; and （ii） between the temperate regions of North and South America （the amphitropical disjunctions）. Both disjunct patterns have multiple times of origin. The amphitropical disjunctions have largely resulted from long-distance dispersal, primarily from the Miocene to the Holocene, with available data indicating that most lineages dispersed from North to South America. Results of recent studies on the Mediterranean disjuncts between the deserts of Eurasia and western North America support the multiple modes of origin and are mostly consistent with hypotheses of long-distance dispersal and the North Atlantic migration. Axelrod＇s Madrean-Tethyan hypothesis, which implies vicariance between the two regions in the early Tertiary, has been favored by a few studies. The Beringian migration corridor for semiarid taxa is also supported in some cases.

Phylogenetic analysis of Toxicodendron(Anacardiaceae) and its biogeographic implications on the evolution of north temperate and tropical intercontinental disjunctions

Toxicodendron is a genus in the Rhus complex of Anacardiaceae with a disjunct distribution between eastern Asia and North America, extending to southeastern Asia and the neotropics. Nuclear （internal transcribed spacer, external transcribed spacer, and NIA-i3） and chloroplast （ndhF and trnL-F） sequences were used to construct phylogenetic relationships of Toxicodendron. Phylogenetic analysis of these data strongly support Toxieodendron as a monophyletic group distinct from other genera of the Rhus complex, and the phylogeny does not fully corroborate classification at the sectional level. Two temperate disjunct lineages were detected, one from section Toxicodendron and the other between the eastern North American Toxicodendron vernix and the eastern Asian Toxicodendron vernieifluum. Their divergence times were estimated to be 13.46 （7.95-19.42） and 7.53 （2.76-12.86） mya, respectively. The disjunction between section Griffithii （taxa from warm temperate to tropical Asia） and Toxieodendron striatum （from the neotropics） was supported and their divergence time was estimated to be 20.84 （11.1 6-30.52） mya in the early Miocene. Our biogeographic results and the paleontological data support the Bering land bridge as the most likely route to explain the temperate disjunctions, yet the tropical disjunction in Toxicodendron seems to be best explained by the North Atlantic land bridge hypothesis.

Counter-regulatory phosphatases TNAP and NPP1 temporally regulate tooth root cementogenesis

Cementum is critical for anchoring the insertion of periodontal ligament fibers to the tooth root. Several aspects of cementogenesis remain unclear, including differences between acellular cementum and cellular cementum, and between cementum and bone. Biomineralization is regulated by the ratio of inorganic phosphate （Pi） to mineral inhibitor pyrophosphate （PPi）, where local Pi and PPi concentrations are controlled by phosphatases including tissue-nonspecific alkaline phosphatase （TNAP） and ectonucleotide pyrophosphatase/phosphodiesterase 1 （NPP1）. The focus of this study was to define the roles of these phosphatases in cementogenesis. TNAP was associated with earliest cementoblasts near forming acellular and cellular cementum. With loss of TNAP in the Alpl null mouse, acellular cementum was inhibited, while cellular cementum production increased, albeit as hypomineralized cementoid. In contrast, NPP1 was detected in cementoblasts after acellular cementum formation, and at low levels around cellular cementum. Loss of NPP1 in the Enppl null mouse increased acellular cementum, with little effect on cellular cementum. Developmental patterns were recapitulated in a mouse model for acellular cementum regeneration, with early TNAP expression and later NPP1 expression. In vitro, cementoblasts expressed Alpl gene/protein early, whereas Enppl gene/protein expression was significantly induced only under mineralization conditions. These patterns were confirmed in human teeth, including widespread TNAP, and NPP1 restricted to cementoblasts lining acellular cementum. These studies suggest that early TNAP expression creates a low PPi environment promoting acellular cementum initiation, while later NPP1 expression increases PPi, restricting acellular cementum apposition. Alterations in PPi have little effect on cellular cementum formation, though matrix mineralization is affected.

狭义蛇葡萄属东亚支系的系统发生与生物地理演化

狭义蛇葡萄属(Ampelopsis s. str.)是葡萄科的落叶木质藤本植物,主要分布在北半球温带地区,特别是东亚为其重要的分布和演化中心。该研究选取了狭义蛇葡萄属15个种的37个样本,对其5个叶绿体基因片段(trnL-F、rps16、psbA-trnH、atpB-rbcL和trnK-petN)和2个核基因标记(ITS和GAI1)进行了分子测序;利用测序获得的分子数据探讨属内的系统发生关系,叶的性状演化以及生物地理起源演化。结果表明:(1)狭义蛇葡萄属是一个单系类群,属内东亚地区的物种聚成一支。(2)叶绿体基因数据分析结果表明,狭义蛇葡萄属东亚支系分为两支系,这两支系的分布范围大致与东亚植物区系的中国-日本森林和中国-喜马拉雅森林亚区范围相一致。(3)形态演化分析表明,掌状复叶为祖征,叶形态性状存在多次的独立起源和演化,其变化与系统进化没有明显的关系。(4)生物地理分析结果表明,狭义蛇葡萄属起源于北美,渐新世晚期至中新世早期迁移扩散至欧洲,中新世中期随着全球气温回暖迁移至东亚,并进一步在东亚地区快速分化形成多样化中心,这可能与中新世时期的气候温暖、受第四纪冰川影响较少以及东亚地区复杂的地形地貌有关。

联合使用电刺激采精与直肠按摩对大熊猫精液采集的影响

研究了实施经直肠按摩输精管壶腹部对大熊猫精液采集的影响。B超检查结果显示，大熊猫具有发达的输精管壶腹部，其位于膀胱与直肠之间；单独实施经直肠按摩输精管壶腹部200～400次后，所有个体均出现程度不等的阴茎勃起，平均阴茎周长从按摩前的6．33cm增加到7．49cm，但是单独使用直肠按摩还不足以刺激大熊猫的射精反应。为确定联合使用直肠按摩与电刺激采精对大熊猫精液采集的影响，开展了进一步实验；电刺激按常规方式进行，在每个刺激系列结束后接着进行直肠按摩100～200次。结果显示，对于电刺激采精量低于1．68mL的个体，直肠按摩可显著增加采精量（P〈0．05），采精量从（0．36±0．66）ml，增加到（0．95±0．99）mL，但是对于电刺激后采精量在1．9mL以上的个体，直肠按摩不能增加采精量。电刺激后进行直肠按摩可将大熊猫采精成功率从44％提高到88％。