Drosophila auraria复合种Period基因Thr-Gly区段的初步研究

测定了金色果蝇复合种（Drosophila auraria species complex）5个姐妹种（sibling species）和D.rufa的period(per)基因的Thr-Gly区段序列。该区段序列分析表明：DNA序列的碱其组成拥有果蝇其他基因的共同特点;颠换数多于转换数,两两种种间的颠换率与转换率的总比值为2～5,密码子第3位的颠换与转换的比值为2.5～5;同义替换/异义替换（Ks/Ka）值远大于10,且有的物种间根本不存在非同义突变,低的Ka值说明该复合种的per基因Thr-Gly区段在进化过程中可能承受着较强的选择压力。运用所得的核苷酸序列构建Drosophila auraria复合种的系统发育树,为澄清该类群的系统演化关系提供了新的线索。     

从D环和细胞色素b基因序列探讨懒猴属的分子系统发育关系(英文)

本研究测定了懒猴属(Nycticebus)D环的部分序列和细胞色素b基因的全序列(1140bp),分析了该属物种之间的系统发育进化关系。在DNA水平上,序列分析结果一致地提供了新的分类学证据：支持Rataiszczak和Groves的观点,即N．intermedus只是N．pygmaeus的成体(Ratajszczak,1998;Groves,1971)。对两种序列的数据做了联合及个别分析,获得相似的系统树,支持懒猴属由两个单系群组成：第一群由N．pygmaeus聚成,第二群由N．coucang聚成。该结果也提供了新的分子遗传证据,支持懒猴属由N．coucang和N．pygmaeus两物种组成。     

蜂猴属（Nycticebus）D-loop控制区和Cyt b基因遗传学研究

测定了蜂猴属线粒体DNA中的D-loop控制区部分序列和细胞色素b基因全序列（1140 bp）,对其变异情况进行了分析,并采用Mega 4.0软件中构建了分子系统树。无论是基于D-loop控制区部分序列构建的系统树,还是基于细胞色素b基因序列构建的分子系统树的拓扑结构图,都清晰地表明蜂猴属由两个分支组成,分支置信度较高,一支由N．pygmaeus聚成,另一支由N．coucang聚成,即支持蜂猴属由N．coucang和N．pygmaeus两物种组成。     

基于线粒体COⅡ基因的中国蝽科分子系统学研究(半翅目,异翅亚目)

扩增并测定了我国蝽科4亚科8属11种昆虫线粒体COⅡ基因585 bp的序列,对序列的碱基组成、转换颠换、遗传距离等进行分析,探讨了COⅡ基因在该科的分子进化机制.并基于COⅡ基因序列数据,分别采用邻接法(NI)、最大简约法(MP)和贝叶斯推论法(BI)建立蝽科分子系统发育关系.研究结果表明,蝽科昆虫COⅡ基因A T含量平均为71.7%,存在较强的A T含量偏向性,氨基酸的变异率为27.2%;亚科间的遗传距离介于0.168～0.242之间,大于亚科内属种间的遗传距离,蝽科与盾蝽科2外群之间遗传距离最大,两科之间存在明显的间断.分子系统发育树表明,短喙蝽亚科为蝽科中较为原始的类群,分化较早,益蝽亚科与舌盾蝽亚科关系较近,形成一对姐妹群,蝽科中捕食性种类--益蝽亚科是较为特化的类群,它是由植食性种类分化而来.蝽科4亚科间的分子系统发育关系为Phyllocephalinae (Pentatominae (Asopinae Podopinae).     

九种绢丝昆虫线粒体12S rRNA基因的序列特征和系统发育分析

为探讨鳞翅目中绢丝昆虫之间的系统发育关系和分子进化特征,本研究测定了中国柞蚕Antheraea pernyi野生型和放养型的线粒体12S rRNA基因的部分序列,结合来自GenBank数据库的17条序列,对总共9种绢丝昆虫（2科3属）的12S rRNA基因序列进行了分析。利用软件MEGA 3.1进行碱基组成、变异位点的统计和分子进化分析,分别用类平均聚类法（UPGMA）、邻接法（NJ）、最小进化法（ME）、最大简约法（MP）重建系统发生树。测定的中国柞蚕野生型的12S rRNA基因序列（427 bp）与放养型“豫早1号”的序列完全一致。序列对齐后共鉴定80个变异位点,50个简约信息位点。碱基组成分析显示在科属间具有明显差异,AT含量蚕蛾科高于大蚕蛾科;在A和T碱基的使用上,大蚕蛾科偏好使用T,而蚕蛾科则偏好使用A。与动物中常见的以转换为主的碱基替换模式不同,所分析的9种昆虫中除桑蚕属内部为转换与颠换基本一致外,其余物种间均是颠换多于转换。进化分析支持柞蚕属、樗蚕属和桑蚕属的单系。基于UPGMA法的进化树支持琥珀蚕是柞蚕属的较原始类型,而NJ、ME和MP法则支持印度柞蚕是较原始的类型,因此,柞蚕属种间的进化关系尚需进一步研究。     

胡颓子科叶绿体基因组系统发育分析与演化趋势推断

【目的】为探索胡颓子科叶绿体基因组演化趋势,从而为胡颓子科植物物种鉴定以及资源开发利用提供理论依据。【方法】研究从头组装并注释了沙棘属（Hippophae）和野牛果属（Shepherdia）共4个类群的叶绿体基因组,结合已发表的叶绿体基因组序列,比较了胡颓子科各类群叶绿体基因组的基因构成、重复序列和结构特征,建立了系统发育树,并通过高分化区定位了该科叶绿体基因组的潜在DNA条形码区域。【结果】胡颓子科各属叶绿体基因组在四分体结构、基因数量和排列上高度相似;沙棘属和野牛果属的反向重复区（IR）和整个基因组重复序列数目较胡颓子属有扩张和增加的趋势。基于胡颓子科18个类群的叶绿体全基因组序列的系统发育树中,胡颓子属、沙棘属和野牛果属各自聚为一支,前者先分化出来,沙棘属和野牛果属有最近共同祖先;从长单拷贝区（LSC）和短单拷贝区（SSC）筛选出3个DNA条形码候选区,其中ycf1基因的鉴定效果最佳,基于此构建的各类群系统发育关系与基于全基因组序列的结果一致。【结论】胡颓子科的叶绿体基因组结构保守,但其非编码区序列在各属间存在明显差异,且IR区序列与重复序列在演化过程中分别有扩张和增多的趋势。研究选定的DNA条形码序列能很好区分胡颓子科各属之间以及胡颓子属内物种间关系。     

SRY基因在人猿超科和旧大陆猴中具有不同的进化规律

通过ＰＣＲ扩增、测序,得到了白臀叶猴和红面猴的ＳＲＹ基因全序列。结合现有的灵长类其他物种序列进行分析,验证了ＨＭＧ盒的保守性。通过构建系统发育树,比较旧大陆猴和人猿超科两个类群内和类群间ＨＭＧ盒侧翼序列Ｋａ／Ｋｓ的比率。有趣的是,人猿超科两物种比较呈现较高的Ｋａ／Ｋｓ比值,但在旧大陆猴中及旧大陆猴与狨猴间的Ｋａ／Ｋｓ比值显著低于人猿超科的,呈现很不同的格局。同时,对于ＨＭＧ盒序列,Ｋａ／Ｋｓ比值在     

基于线粒体COⅠ基因的海陵岛鲷科鱼类系统发育分析

对采自海陵岛的6种鲷科鱼类(Sparidae)86个个体的线粒体COⅠ基因进行测序,结合Gen Bank上的17条同源序列,共7属11种103个个体进行系统进化分析。海陵岛11种鲷科鱼类COⅠ基因序列的T、C、A、G的平均含量分别为31.9%、27.6%、23.4%和17.1%,有保守位点359个,变异位点165个,简约信息位点162个,序列中转换大于颠换。Kimura 2-parameter种间遗传距离显示,真赤鲷和二长棘犁齿鲷的遗传距离小于前者与蓝点赤鲷的遗传距离。应用邻接法(NJ法)和最大似然法(ML法)对103条序列分别构建了鲷科鱼类的分子系统进化树。结果显示,鲷科鱼类分为两大类群,一类包括犁齿鲷属、赤鲷属、牙鲷属和四长棘鲷属,另一类包括平鲷属、棘鲷属和拟牛眼鲷属。根据种间遗传距离与系统发育树的结构特征推测,真赤鲷与二长棘犁齿鲷可能属于同一属,这与传统的形态分类学观点不完全相符。     

基于线粒体ND2基因的中国斑翅蝗科部分种类分子系统学研究（直翅目：蝗总科）

本文的目的是通过对斑翅蝗科部分种类的线粒体ND2基因进行分析,重建斑翅蝗科昆虫的系统发育关系,并探讨分子系统发育关系和传统分类结果的异同。扩增并测定了我国斑翅蝗科10属16种蝗虫的线粒体ND2全基因1 023 bp的序列,对序列的碱基组成、转换颠换、系统发育信号等进行了分析。并基于ND2全基因序列数据,分别采用邻接法（NJ）、最简约法（MP）、最大似然法（ML）和贝叶斯法重建了10属16种蝗虫的系统发育关系。结果表明：斑翅蝗科蝗虫ND2全基因A+T含量平均为74.6%;痂蝗亚科和异痂蝗亚科没能得到区分,建议合并为一个亚科;而斑翅蝗亚科和飞蝗亚科的分类地位还存在争议。     

从1 2S rRNA基因序列探讨8种鳄类的系统学关系

测得扬子鳄（Alligator sinensis）和暹罗鳄（Crocodylus siamensis）,的mtDNA12SrRNA基因片段的部分序列,与GenBank中的2种鳄及文献中4种鳄的12SrRNA基因相应片段,经比对后构建系统树。其结果显示,现存鳄类为单系起源,可划分为3个科,即：鳄科、食鱼鳄科和假食鱼鳄科。食鱼鳄与假食鱼鳄亲缘关系较近,支持将假食鱼鳄作为食鱼鳄科的一个属,与以形态学为基础的研究结果不同。在钝吻鳄科中,扬子鳄与凯门鳄亲缘关系较远,而与密西西比鳄的亲缘关系虽较近,但它们的确存在很多差异。两者12SrRNA基因序列差异达12．12％,碱基的颠换数为9。在基于碱基转换和颠换的NJ系统树及仅基于碱基颠换的NJ系统树中,前者支持扬子鳄与密河鳄间的亲缘关系较近,而后者支持扬子鳄与凯门鳄间的亲缘关系较近,说明扬子鳄与密河鳄间亲缘关系是值得研究的问题。因本文仅根据12SrRNA基因部分序列来进行分析的,尚需进一步研究。     

懒猴属的核糖体DNA变异及其种间分化关系

用１５种限制性内切酶和人２８Ｓ、１８ＳｒＤＮＡ探针构建了懒猴属各物种核糖体ＤＮＡ重复单位的限制性内切酶图谱。在进化速率较高的非转录间隔区,在大、中、小懒猴中分别定位了２３、２４、２４个酶切位点。大懒猴与中懒猴有１２个位点不同,与小懒猴有１４个位点不同,而中、小懒猴间则只有一个位点的差异。经过计算,大懒猴与中懒猴的遗传距离值为１２．６５％,与小懒猴的差异为１４．２４％,中、小懒猴间的差异则仅为０．７     

Cytochrome b sequences reveal Acomys minous (Rodentia, Muridae) paraphyly and answer the question about the ancestral karyotype of Acomys dimidiatus

Sequences of the cytochrome b (cyt b) mitochondrial gene show that the spiny mouse Acomys from Crete, known as the endemic species A. minous, is composed of two distinct maternal lineages ("A" and "B"). Group "A" sequences cluster with A. nesiotes (Cyprus) and group "B" sequences cluster with A. cilicicus (Turkey), which is evidence of paraphyly of A. minous in regard to these two species. From cyt b sequences, the three taxa are very closely related to A. cahirinus (Egypt): the maximum divergence found among these sequences is 1.6%, which is equivalent to the intraspecific diversity observed in other Acomys species. Paleozoology evidenced that man unintentionally introduced Acomys into Crete and Cyprus during antiquity. The divergence time between Acomys cyt b sequences found in Crete was estimated at 0.4 Myr, which means that the diversity observed did not appear after the introduction but reflects a much more ancient polymorphism. Cytochrome b phylogeny and cytogenetic data together comprise evidence that, within the species A. dimidiatus (Saudi Arabia, Israel, Egypt), it is the karyotypic form with 36 chromosomes that derives from the form with 38 chromosomes, due to a single acrocentric fusion.     

Cytogenetics of two Lorisidae (Nycticebus coucang and Perodicticus potto). Comparison with the lemurs and the simians (author's transl)]

The karyotypes of two Lorisidae (Prosimians) Nycticebus coucang and Perodicticus potto have been studied, using many banding techniques. These karyotypes are compared with each other and also with those of Microcebus murinus (Lemur) and of Cebus capucinus (Simian, platyrrhine). The karyotype of M. murinus appears ancestral to the other. That of the Lorisidae cannot be an intermediatry stage between the karyotypes of the lemurs and of the simians. An important part (12 p. cent) of the genome of N. coucang is comprised of heterochromatin ; it and the juxta centromeric heterochromatin stain negatively with C-banding techniques. C-banding therefore is insufficient to delineate constitutive heterochromatin, late replication being the only universal criterion.     

从细胞色素b 基因全序列分析岩羊和山羊、绵羊的系统发生关系

本文测定了来自四川和青海岩羊的细胞色素b 基因全序列(1 140 bp) , 结合从GenBank 中检索获得的山羊、北山羊、绵羊和盘羊4 个近缘种细胞色素b 核苷酸同源区序列进行比较, 分析了碱基组成和变异情况以及核苷酸序列差异。分别采用简约法和距离矩阵法构建分子系统树, 得到了基本相同的拓扑结构, 从分子水平初步探讨了岩羊的系统起源问题。岩羊与山羊属的山羊、北山羊有着比绵羊属的绵羊、盘羊更近的亲缘关系。岩羊与山羊、北山羊的分歧时间大约在3～6 百万年, 而与盘羊、绵羊的分歧时间大约在6～8 百万年。     

Molecular phylogeny of avian genus Syrmaticus based on the mitochondrial cytochrome B gene and control region

Mitochondrial DNA cytochrome b (cyt b) and control region (CR) nucleotide sequences were used to study the molecular phylogeny of the genus Syrmaticus. We found that the substitution rates among the three codon positions of cyt b were heterogeneous and the transition-transversion ratio was highly biased. As to CR sequences of the genus, most variable sites were in the peripheral domains. All molecular phylogenetic trees based on the two genes showed that: 1) the Syrmaticus was monophyletic and included five species with the following cladistic relationship: (S. reevesii, (S. soemmerringii, (S. mikado, (S. humiae and S. ellioti)))). Using the TN genetic distance of cyt b, we inferred the divergence time of the five species according to putative molecular clock and found that values were largely in agreement with the geological scenarios. The origin and speciation processes of the studied group were inferred by combining molecular and biogeographical evidences.     

Exhaustive sample set among Viverridae reveals the sister-group of felids: the linsangs as a case of extreme morphological convergence within Feliformia

Although molecular studies have helped to clarify the phylogeny of the problematic family Viverridae, a recent phylogenetic investigation based on cytochrome b (cyt b) has excluded the Asiatic linsangs (genus Prionodon) from the family. To assess the phylogenetic position of the Asiatic linsangs within the Feliformia, we analysed an exhaustive taxonomic sample set with cyt b and newly produced transthyretin intron I sequences (TR-I-I). TR-I-I alone and cyt b +TR-I-I combined (maximum-likelihood analysis) highly support the position of Asiatic linsangs as sister-group of the Felidae. The estimation of minimum divergence dates from molecular data suggests a splitting event ca. 33.3 million years (Myr) ago, which lends support to historical assertions that the Asiatic linsangs are "living fossils" that share a plesiomorphic morphotype with the Oligocene feliform Paleoprionodon. The African linsang is estimated to appear more than 20 Myr later and represents the sister-group of the genus Genetta. Our phylogenetic results illustrate numerous morphological convergences of "diagnostic" characters among Feliformia that might be problematic for the identification of fossil taxa. The morphotype reappearance from the Asiatic to the African linsangs suggests that the genome of the Feliformia conserved its potential ability of expression for a peculiar adaptive phenotype throughout evolution, in this case arboreality and hypercarnivory in tropical forest.     

Characterization of the Agamid Lizard Genus Uromastyx from Eastern Sudan Based on Morphology,Karyotypes and Mitochondrial DNA

This study focuses on taxonomy of Uromastyx species. Morphologically, U. ocellata and U. ornata were identified and cytogenetically, 2n = 36 chromosome. 16S, cyt b and 12S genes fragmentamplification shows 597, 399 and 450 base pair respectively and more A-T than G-C base pair andmore A/C than T/G base contents. While, sequences blasting in GenBank, followed by construction of phylogenetic tree revealed, 16S and cry b sequences were similar to U. ocellata sequences, andclustered together in phylogenetic tree, in contrast, 12S sequences from same species were related tosubspecies U. ornata ornata sequences and clustered together in the phylogenetic tree. Therefore, the results of this study suggest more studies on Uromastyx species in Sudan.     

Monophyletic Origin of Alu Elements in Primates

To get insight into the early evolution of the primate Alu elements, we characterized sequences of these repeats from the Malagasy prosimians, lemurs (Lemuridae) and sifakas (Indriidae), as well as from galagos (Lorisidae). These sequences were compared with the oldest Alu species known from the human genome: dimeric Alu J and S and free Alu monomers. Our analysis indicates that about 60 Myr ago, before the prosimian divergence, free left and right monomers formed an Alu heterodimer connected by a 19-nucleotide-long A-rich linker. The resulting elements successfully propagated in diverging primate lineages until about ∼20 Myr ago, conserving similar sequence features and essentially the same Alu RNA secondary structure. We suggest that until that time the same ``retropositional niche', molecular machinery making possible the proliferation by retroposition, constrained the evolution of Alu elements in extant primate species. These constraints became subsequently relaxed. In the Malagasy prosimians the dimeric Alu continued to amplify after acquiring a 34- to 36-nucleotide extension of their linker segment, whereas in the galago genome the ``retropositional niche' was occupied by novel short elements. Received: 1 December 1997 / Accepted: 30 January 1998