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。     

中国东北地区黑腹果蝇（Drosophila melanogaster）P因子分布和来源

真核生物的转座因子(transposable elements)特别是果蝇P因子在研究生物进化上有重要的意义。以我国东北地区13个地方及毗邻的北京、烟台和呼和浩特三个地方共130个黑腹果蝇(D.melanogaster)单雌系为材料,对P因子序列的ORF2-ORF3区段进行PCR扩增,统计不同地方黑腹果蝇群体的P因子在此区段的缺失频率,再从整个地区来分析P因子缺失的分布规律,以推导东北地区黑腹果蝇中P因子的传递和扩散途径。结果显示P因子缺失频率由边境地区向内地逐渐递减,群体相对隔离的地方也较低,推断我国东北地区黑腹果蝇中P因子由朝鲜和俄罗斯向中国边境入侵后,逐步向中国内地扩散。     

中国东北地区黑腹果蝇(Drosophila melanogaster)P因子分布和来源

真核生物的转座因子(transposable elements)特别是果蝇P因子在研究生物进化上有重要的意义。以我国东北地区13个地方及毗邻的北京、烟台和呼和浩特三个地方共130个黑腹果蝇(D.melanogaster)单雌系为材料,对P因子序列的ORF2-ORF3区段进行PCR扩增,统计不同地方黑腹果蝇群体的P因子在此区段的缺失频率,再从整个地区来分析P因子缺失的分布规律,以推导东北地区黑腹果蝇中P因子的传递和扩散途径。结果显示P因子缺失频率由边境地区向内地逐渐递减,群体相对隔离的地方也较低,推断我国东北地区黑腹果蝇中P因子由朝鲜和俄罗斯向中国边境入侵后,逐步向中国内地扩散。     

双齿果蝇物种群Lordiphosa denticepsgroup的分类地位及四新种记述(双翅目:果蝇科)

Okoda(1967)以Drosophila(Hirtodrosophila)denticeps和D.(Hirtodrosophila)tripartita建立双齿果蝇物种群denticeps group,隶毛果蝇亚属Hirtodrosophila之下。他最近(1990)又将该物种群归入拱背果蝇亚属Lordiphosa,为黑色拱背果蝇物种群nigricolor group的同物异名。Grimaldi(1990)采用分支分类分析法对果蝇科各属间的系统发育关系进行分析,据单源群原则及7个离征将挑背果蝇亚属恢复为属。本文采用     

MicroRNA在果蝇原始生殖细胞命运调控中的功能研究

果蝇原始生殖细胞(primordial germ cells,PGCs)是生殖干细胞的前体。该群细胞在果蝇幼虫期经历特征性的发育过程,这一过程涉及程序化的细胞命运及行为改变。为系统探讨mi RNA在上述PGCs命运调控中的作用,对雌蝇幼虫发育中的性腺组织进行了mi RNA表达谱分析,发现一组mi RNA分子持续在性腺组织细胞中表达。应用GAL4/UAS遗传操作系统验证了部分候选mi RNAs的功能,获得了mi R-33和mi R-278参与调控果蝇幼虫PGCs有序分化的实验证据。该文为发育过程中功能性mi RNA研究工作的开展提供了有益的借鉴。     

黄体（yellow^0）是果蝇小体重的一个标记

标记辅助选择（marker-assisted selection,MAS）是现代育种的一种重要手段,但是在研究中经常发现与数量性状基因座位（quantitative trait loci,QTL）连锁的标记效应不稳定,这使得MAS在动物育种中成功应用的报道很少,人们甚至怀疑MAS在实际应用中的效果.本研究首次利用模式生物果蝇来研究是否能够找到应用到MAS中的有效标记.采用F2设计将带有黄体（y^0）标记（X染色体上yellow基因的一个隐性突变）的品系分别与3个不带此标记的品系进行正反杂交,结果发现F2代中,y^0标记与小体重显著相关（P〈0.001）,而且这种相关不随遗传背景的改变而消失.标记效应在雌雄中分别达到了0.95σP（表型标准差）和0.68σP.以y^0为标记,通过20代标记辅助导入（marker-assisted introgression,MAI）,将y^0所处的DNA区段导入到野生型品系中,结果使野生型雌雄体重分别降低了13%和7%（P〈0.0001）,从而成功建立了小体重果蝇品系,实验证明确实存在一个与y^0紧密连锁的小体重QTL.利用y^0标记和白眼（white）标记进行深度MAI,进一步将一个小于1.5cM的y^0标记区段导入到野生型品系中,同样导致了野生型果蝇相同程度的体重降低.可见,果蝇的小体重QTL位于y^0标记区段,遗传距离不超出1.5cM的范围.PCR和Southern杂交的结果显示,此标记处的y基因发生了缺失,可能影响了果蝇的正常生长发育.本实验充分证明,应用到MAS育种中的QTL有效标记是存在的,并且可以用于培育新的品系.     

家蚕EGFR配体的鉴定和验证

表皮生长因子受体(EGFR)是广泛存在于后生动物中的多功能受体,其配体的种类、活化方式、配体与EGFR之间的相互作用以及激活的信号通路在哺乳动物中研究得较为深入。而非脊椎动物中,EGFR配体在各物种间差异较大,目前缺乏对除果蝇以外的其他昆虫EGFR配体的认识。通过同源比对、结构域预测、m RNA翻译起始序列分析和系统进化树构建,在家蚕中鉴定到2个EGFR的配体,命名为Bm EGF-1和Bm EGF-2。Bm EGF-1与果蝇Spitz有较高的同源性和一致的Rhomboid识别序列,Bm EGF-2为Vein的同源分子。经原核表达和纯化获得了Bm EGF-1胞外区段,利用Sf9细胞分泌Bm EGFR胞外区段,并通过pull-down实验验证了两者之间存在相互作用。在Bm E细胞中表达Bm EGF-1后,通过Western blotting检测到ERK和p38 MAPK的磷酸化水平增强,说明其不仅能激活经典的ERK信号通路,还可能通过p38 MAPK信号通路参与其他生理过程,为进一步研究EGFR配体在家蚕中的生物学功能提供了参考。     

果蝇Drosophila saltans种亚组（双翅目：果蝇科）系统发育关系：形态学能否解决分子冲突？

正确的系统发生重建对于理解进化事件至关重要.尽管分子系统学对于解决此类问题取得了极大的成功,由于一些诸如密码子使用偏性等的内在约束,来源于DNA的信息可能仍然存在着局限.因为发生在祖先的替代性转换,果蝇Drosophila saltans 5个种亚组由不同基因构建的分子系统树之间存在着冲突(在以往发表的分子系统学研究中,这些种组的每一个种亚组全少有一个代表).本文用40个形态学特征重新分析了这些种组.不同于以前发表的大多数假说,本研究支序分类学的结果表明,果蝇sturtevanti种亚组是一个较早的分支,而剩下的4个亚组形成一个支持度较高的类群;后者又可以再分为两个姐妹群:一个包含cordata和elliptica亚组,另一个包含parasaltans和saltans亚来组.本研究结果修正了果蝇saltans种组的分子进化(密码子使用偏性),并强调形态学对于系统发生重建和理解分子进化现象的重要作用.     

基于果蝇口腔感染的肠道训练免疫模型研究（英文）

目的 利用果蝇作为遗传工具从个体和分子层面研究果蝇的训练免疫效应,并为后续深入研究其分子机制提供依据。方法 首先构建无菌果蝇模型,在此基础上构建果蝇成虫及跨发育阶段训练免疫模型,用两种革兰氏阴性菌——胡萝卜软腐欧文氏菌（Erwinia carotovora carotovora 15）及铜绿假单胞菌（Pseudomonas aeruginosa）分别经口腔感染果蝇。在第一次感染完全消退后进行再次感染,然后通过比较果蝇在两个感染阶段的存活率和细菌量来衡量训练免疫的潜在效果。通过实时荧光定量PCR检测相应先天免疫相关基因的表达水平,研究革兰氏阴性菌对免疫缺陷（IMD）通路的诱导作用。结果 果蝇成虫及幼虫初次感染均可提高二次感染后的生存率、细菌清除效率及死亡时能承受的最高细菌负荷;二次感染的果蝇中,IMD通路中免疫反应基因的基础表达比未感染的高,这提供了获得感染抗性的分子基础;果蝇的免疫反应主要发生在中肠,二次免疫比初次免疫的效应更迅速且剧烈;二次免疫的果蝇中,肠道干细胞的数量显著多于初次感染。结论 果蝇肠道中强大的训练免疫可由同源或异源革兰氏阴性菌口腔感染引发,且免疫记忆可在整个发育阶段持...     

利用帕金森症的果蝇模型测试具有神经保护作用的化学活性分子(英文)

帕金森症的果蝇模型对解析疾病的分子细胞机制贡献极大.为探讨利用地中海黑腹果蝇的疾病模型来筛选新型治疗帕金森症药物的可能性,我们构建了基于DJ-1A和PINK1两个遗传致病因子的帕金森症果蝇模型,测试抗氧化和消炎活性分子米诺环素和辅酶Q10对脑多巴胺浓度的影响.结果表明,米诺环素对DJ-1A果蝇模型有明显保护作用,能显著提高脑多巴胺的浓度,但是对PINK1果蝇模型没有保护作用;辅酶Q10对两种模型均有保护作用.因此,帕金森病的果蝇模型能够反映药物分子的特异性作用,为筛选新的帕金森病治疗药物提供了一条便捷的途径.     

伊米果蝇种组（Drosophila immigrans species group）H2a-H2b和Cyt b分子系统发育关系（简报）

伊米果蝇种组(Drosophila immigrans speciesgroup)是果蝇科(Drosophilidae)、果蝇属(Drosophi-la)、果蝇亚属(Drosophila)中数量最多的一个类群,主要分布于东洋区。在分类学上该种组分为nasuta、immigrans、hypocausta、quadrilineata和curviceps五个种亚组(species subgroup)[1],东洋区果蝇区系中伊米果蝇种组中包括94个种,其中有45个种分布在中国[2]。而且curviceps种亚组是1992年新建立的中国特有果蝇类群[3]。迄今,对伊米果蝇种组分子系统关系的报道还很少,有些物种的归属仍存在争议。伊米果蝇种组还有些问题需要探讨[4]。组蛋白基因…     

Hybridization and introgression of the genomes of Drosophila nasuta and Drosophila albomicans: evolution of new karyotypes.

Drosophila nasuta (2n = 8) and Drosophila albomicans (2n = 6) are cross-fertile allopatric sibling chromosomal races of the nasuta subgroup of Drosophila. Hybrids of these races can be maintained for any number of generations. Some of the introgressed hybrid lineages of D. nasuta and D. albomicans, after passing through a transient phase of karyotypic polymorphism, ended up with a stable karyotype whose composition is different from those of the parental races. Such hybrid populations were called cytoraces, in which the chromosomes of D. nasuta and D. albomicans are represented in different combinations. The karyotypic composition of 16 such cytoraces have been presented and discussed with reference to evolutionary strategies such as balancing selection, directional selection, and sex-specific effect on different components of the evolving karyotypes.     

果蝇Drosophila nasuta亚群系统发育问题的探讨

果蝇Ｄｒｏｓｏｐｈｉｌａｎａｓｕｔａ亚群由在１４个处于不同物种分化阶段的种,亚种和分类元组成,这个亚群的物种有许多进化上的独特之处,使得它在物种分化研究方面倍受关注,然而,在形态学,生殖隔离,染色体和同工酶多态,线粒体ＤＮＡＲＦＬＰ,求偶歌特征惟及线粒体和核基因序列分析等方面的研究都未能清楚地阐明这一亚群的系统进化关系,本文综合分析了关于这一亚群的进化遗传学的研究结果,并提出了有待进一步的一些问题     

The speciation history of the Drosophila nasuta complex

The Drosophila nasuta subgroup of the immigrans species group is widely distributed throughout the South-East Asian region, consisting of morphologically similar species with varying degrees of reproductive isolation. Here, I report nucleotide variability data for five X-linked and two mtDNA loci in eight taxa from the nasuta subgroup, with deeper sampling from D. albomicans and its sister species D. nasuta. Phylogenetic relationships among these species vary among different genomic regions, and levels of genetic differentiation suggest that this species group diversified only about one million years ago. D. albomicans and D. nasuta share nucleotide polymorphisms and are distinguished by relatively few fixed differences. Patterns of genetic differentiation between this species pair are compatible with a simple isolation model with no gene flow. Nucleotide variability levels of species in the nasuta group are comparable to those in members of the melanogaster and pseudoobscura species groups, indicating effective population sizes on the order of several million. Population genetic analyses reveal that summaries of the frequency distribution of neutral polymorphisms in both D. albomicans and D. nasuta generally fit the assumptions of the standard neutral model. D. albomicans is of particular interest for evolutionary studies because of its recently formed neo-sex chromosomes, and our phylogenetic and population genetic analyses suggest that it might be an ideal model to study the very early stages of Y chromosome evolution.     

Molecular phylogeny of the nasuta subgroup of Drosophila based on 12S rRNA, 16S rRNA and CoI mitochondrial genes, RAPD and ISSR polymorphisms

The nasuta subgroup is a cluster of morphologically almost similar forms with a wide range of geographic distribution. During the last three decades nature of inter-relationship among the members has been investigated at different levels of organization. The phylogenetic relationships of the members of the nasuta subgroup of the immigrans species group of Drosophila was made by employing Random Amplified Polymorphic DNA (RAPD), Inter Simple Sequence Repeats-PCR (ISSR-PCR) polymorphisms, mitochondrial 12S rRNA, 16S rRNA and Cytochrome C Oxidase subunit I (CoI) gene sequences. The phylogenetic tree generated by RAPD analysis is in nearly complete congruence with the classification based on morphophenotypic characters. The 12S and 16S rRNA genes were highly conserved across the nasuta subgroup and revealed only 3 and 4 variable sites respectively, of which only one site was informative. The CoI gene, on the other hand, revealed 57 variable sites of which 25 sites were informative. All the three species of orbital sheen complex were included in a major cluster in the phylogenetic trees derived from mitochondrial gene sequence data consistent with the morphophenotypic classification. The CoI analysis placed two species of frontal sheen complex, D. n. nasuta and D. n. albomicans in two different clades and this is inconsistent with morphological classification. The molecular clock suggested that divergence between the kohkoa complex and the albomicans complex occurred approximately 2.2 MYA, indicating recent evolution of the nasuta subgroup. The higher transition bias in the mitochondrial genes reported in the present study also suggested recent evolution of the nasuta subgroup.     

Metaphase chromosomes of four species of the Drosophila nasuta subgroup

Metaphase chromosomes of four species of the Drosophila nasuta subgroup, D. nasuta, D. kepulauana, D. kohkoa, and D. neveifrons, were analysed by the C banding method to clarify the chromosomal differentiation during speciation. Four species were different in heterochromatic regions of their chromosomes, especially microchromosomes of the fourth chromosomes and the Y chromosomes. Intraspecific variations of heterochromatic regions were also found among isofemale lines from various localities of D. nasuta, D. kepulauana, and D. kohkoa. Intraspecific variations of heterochromatic regions were not different from interspecific variations morphologically. From these results, the evolutionary process of heterochromatic regions was discussed.     

A Mutation in Drosophila simulans that Lengthens the Circadian Period of Locomotor Activity

The length of the Thr-Gly repeat within the period gene of Drosophilids, coevolves with its immediate flanking region to maintain the temperature compensation of the fly circadian clock. In Drosophila simulans, balancing selection appears to maintain a polymorphism in this region, with three repeat lengths carrying 23, 24 or 25 Thr-Gly pairs, each in complete linkage disequilibrium with a distinctive flanking region amino acid moiety. We wondered whether separating a specific length repeat from its associated flanking haplotype might have functional implications for the circadian clock. We fortuitously discovered a population of flies collected in Kenya, in which a chimeric Thr-Gly haplotype was segregating that carried the (Thr-Gly)24 repeat, but the flanking region of a (Thr-Gly)23 allele. One of the five isofemale lines that carried this 'mutant' Thr-Gly sequence showed a dramatically long and temperature-sensitive free-running circadian period. This phenotype was mapped to the X chromosome, close to the D. simulans per gene, but there was also a significant effect of a modifying autosomal locus or loci. It seems remarkable that such a mutant phenotype should be discovered in a screen of chimeric Thr-Gly regions.     

Linkage disequilibrium, mutational analysis and natural selection in the repetitive region of the clock gene, period, in Drosophila melanogaster

We have used the method of disequilibrium pattern analysis to examine associations between the threonine-glycine (Thr-Gly) encoding repeat region of the clock gene period (per) of Drosophila melanogaster, and polymorphic sites both upstream and downstream of the repeat, in a number of European fly populations. The results are consistent with the view that selection may be operating on various haplotypes which share the Thr-Gly length alleles encoding 17, 20 and 23 dipeptide pairs, and that the repeat itself may be the focus for selection. These conclusions lend support to a number of other population and behavioural investigations which have provided evidence that selection is acting on the Thr-Gly region. The linkage analysis was also used to infer an approximate mutation rate (mu) for the repeat, of 10(-5) < mu < 4 x 10(-5) per gamete per generation. Direct measurements of the mutation rate using the polymerase chain reaction in a pedigree analysis of tens of thousands of individuals do not contradict this value. Consequently, the Thr-Gly repeat does not have a mutation rate that is as high as some of the non-coding minisatellites, but it is several orders of magnitude higher than the nucleotide substitution rate. The implications of this elevated mutation rate for linkage disequilibria and selection are discussed.     

果蝇nasuta亚群求爱歌的种间识别与进化遗传学研究

果蝇ｎａｓｕｔａ亚群由１４个种、亚种和分类群组成,广泛分布于印度－太平洋区域。本文首次记录了ｎａｓｕｔａ亚群种的求爱歌,测量了脉冲歌时域模式的参数：脉冲串间隔（ＩＢＩ）、脉冲间隔（ＩＰＩ）、脉冲串时间长度（ＰＴＬ）、每个脉冲串的脉冲数（ＰＮ）、脉冲时间长度（ＰＬ）、波动周期时间长度（ＣＬ）。采用计算机声谱分析技术,作出求爱歌信号的三维数字功率谱图,进行频率分析。发现Ｄ．ｐｕｌａｕｎａ和Ｔａｘｏｎ－Ｆ不发出求爱歌声信号,视觉在交配中可能起重要作用。对其余种、亚种和分类群的求爱歌分析表明,ｎａｓｕｔａ亚群种的求爱歌分为脉冲歌和正弦歌。对部分种的正反交Ｆ１求爱歌分析表明,脉冲歌时域参数,如ＩＰＩ平均值为Ｘ染色体连锁或常染色体多基因控制,正弦歌频率偏向母方。根据不同种、亚种和分类群脉冲歌的时域模式构建ｎａｓｕｔａ亚群的系统树,对亚群中不同种、亚种和分类群的亲缘关系进行讨论。