拟南芥AtCIPK23基因对烟草抗旱能力的影响

为了探索拟南芥AtCIPK23基因对烟草耐旱能力的影响,对3个转AtCIPK23基因阳性纯合株系KA13、KA14和KA44与野生型烟草K326（对照）进行了自然干旱处理,测定离体叶片的失水速率、叶绿素含量、相对电导率、脯氨酸和可溶性糖含量,并分析了转基因及野生型材料对活性氧的清除能力,对活性氧清除基因NtSOD、NtCAT和NtAPX及干旱胁迫相关基因NtDREB、NtLEA5和NtCDPK2的表达量进行检测。结果表明：（1）转基因烟草离体叶片的失水速率明显低于K326;自然干旱7 d后,野生型K326出现了明显的干旱胁迫症状;干旱7 d进行复水后,转基因株系的复水存活率明显高于K326。（2）转基因株系中的叶绿素、脯氨酸及可溶性糖含量比K326显著提高,电导率则明显降低。（3）野生型烟草K326中H₂O₂的积累量明显高于3个转基因株系,转基因株系中ROS清除机制的3个关键基因NtSOD、NtCAT和NtAPX被诱导上调表达。（4）抗旱相关基因NtDREB、NtLEA5和NtCDPK2仅在转基因烟草中受干旱诱导。研究认为,AtCIPK23基因可能具有提高植物抗旱能力的功能。     

番茄SlWRKY31基因启动子的克隆与逆境应答模式分析

该研究以野生型番茄（Solanum lycopersicum）为材料,采用PCR技术克隆得到了番茄 SlWRKY31 基因起始密码子 ATG 上游启动子序列,并利用该启动子驱动 GUS基因在野生型番茄中表达,对获得的转基因番茄采用不同胁迫处理后进行GUS 染色和定量分析。结果表明：（1）序列分析显示,该启动子全长1 849 bp,含有多个与非生物胁迫和激素响应相关的顺式作用元件,主要包括热胁迫响应元件 HSE、干旱诱导响应元件 MBS、防卫和胁迫响应元件 TC rich repeats、创伤诱导响应元件 WUN motif、脱落酸（ABA）响应元件 ABRE 和水杨酸（SA）响应元件 TCA element。（2）实时荧光定量 PCR 结果显示,SlWRKY31 基因呈组成型表达模式,且在叶和果实中表达量较高,茎中较低;在NaCl、甘露醇、SA、ABA 和42 ℃ 高温的胁迫处理下,其表达量显著升高。（3）构建 SlWRKY31 启动子和 GUS 基因融合的植物表达载体,并通过农杆菌介导法将其转化野生型番茄,对获得的转基因番茄进行 GUS 组织化学染色分析结果显示,SlWRKY31 基因在番茄的各个组织（根、茎、叶、花、果实和种子）中均有表达,表明 SlWRKY31 启动子是组成型表达启动子。（4）对转基因番茄在不同胁迫处理后的 GUS 染色和定量分析显示,SlWRKY31 启动子显著受到NaCl、甘露醇、SA、ABA 和42 ℃ 高温的诱导表达,说明该启动子是一个可以响应多种逆境胁迫的诱导型启动子。     

桃Pp4CL2基因的克隆及抗寒功能验证

基于‘丁家坝李光桃’抗寒转录组数据,采用RT PCR技术克隆桃4 香豆酸辅酶A连接酶基因(Pp4CL2),并对其进行生物信息学及转化模式植物拟南芥和烟草的抗寒分析,以解析‘丁家坝李光桃’的抗寒机制。结果显示：(1)成功克隆获得桃Pp4CL2基因(登录号：LOC18792923),其cDNA序列为1 635 bp,编码544个氨基酸残基,具有4CL基因家族保守结构域。(2)二级结构分析显示,Pp4CL2蛋白由4种状态的二级结构组成,其中α螺旋占30.51%、β 折叠占7.35%、不规则卷曲及延伸链分别占41.54%和20.59%。(3)顺式作用元件分析发现,Pp4CL2基因上游启动子区含有光、低温以及多种激素响应元件。(4)序列系统进化分析显示,桃Pp4CL2与杏(Prunus armeniaca)、欧洲甜樱桃(Prunus avium)和梅(Prunus mume)的蛋白相似性最高,分别为99.08%、97.98%和96.14%。(5)成功构建转化载体Pp4CL2 pRI101,对拟南芥和烟草进行遗传转化并通过PCR鉴定获得转基因拟南芥和烟草。(6)与野生型相比,低温胁迫下转基因拟南芥和烟草的Pp4CL2基因相对表达量高,受冷害程度轻,具有更高的渗透调节物质含量和抗氧化酶活性,对低温具有更强的耐受性。研究表明,过表达Pp4CL2基因可增强植物对低温的耐受性,推测Pp4CL2基因在‘丁家坝李光桃’响应低温胁迫过程中具有重要作用。     

烟草NtSKOR1基因的克隆及功能分析

该研究利用拟南芥AtSKOR蛋白序列,通过NCBI的Blast搜索获得烟草NtSKOR1基因CDS序列。设计全长CDS扩增引物,通过RT PCR方法从栽培烟草中克隆得到NtSKOR1基因,对其进行生物信息学、表达特性等分析,并利用CRISPR/Cas9技术获得NtSKOR1的敲除材料。结果表明：(1)NtSKOR1基因CDS由2 466 bp核苷酸组成,编码821个氨基酸,推测NtSKOR1蛋白等电点为6.36,分子量为94.21 kD。(2)NtSKOR1定位于细胞膜,有6个跨膜区,无信号肽序列;NtSKOR1蛋白含有孔形成区(P)及锚定蛋白区(ANK)等典型SKOR类蛋白功能域。(3)进化树分析表明,烟草NtSKOR1蛋白与番茄和马铃薯的SKOR蛋白遗传距离最近,与禾本科植物的SKOR蛋白遗传距离较远。(4)组织特异性表达分析表明,NtSKOR1基因主要在烟草根中表达,其表达模式与拟南芥一致;钾胁迫处理后,NtSKOR1基因呈先降低后升高再降低的表达模式。(5)CRISPR/Cas9敲除NtSKOR1基因,烟草叶片钾含量显著降低,表明NtSKOR1基因是控制烟叶钾离子的关键基因之一。该研究结果为解析烟草钾离子吸收转运的分子机制提供重要依据。     

忽地笑LaSUVH1基因克隆与功能分析

为了深入探究忽地笑(Lycoris aurea)组蛋白赖氨酸甲基转移酶(histone lysine methyltransferase, HKMT)基因的功能,该研究根据前期转录组测序结果,采用RT PCR方法克隆得到一个组蛋白赖氨酸甲基转移酶基因LaSUVH1。序列分结果表明, LaSUVH1基因的编码区(coding sequences, CDs)序列长2 007 bp,编码668个氨基酸残基;LaSUVH1蛋白不具有信号肽结构,无跨膜结构,为亲水性蛋白,含有SET、YDG/SRA、Pre SET和Post SET结构域;序列比对和系统进化树分析发现,LaSUVH1与芦笋AoSUVH1 like蛋白亲缘关系最近。实时荧光定量PCR分析表明,LaSUVH1基因在忽地笑不同组织部位均有表达,且在叶中表达量最高。经潮霉素筛选成功获得3个反义过表达LaSUVH1的转基因拟南芥株系。进一步功能分析发现,反义过表达LaSUVH1促进了拟南芥幼苗侧根的发生,降低了拟南芥对NaCl的耐受性,增加了拟南芥种子萌发对脱落酸(ABA)的敏感性,表明LaSUVH1基因响应盐胁迫应答可能依赖ABA信号通路。     

三倍体枇杷花期调控基因EjAGL6的表达特性和功能分析

以三倍体枇杷(Eriobotrya japonica) ‘华玉无核1号’的花芽为材料,采用基因克隆技术获得EjAGL6基因,分析其序列、亚细胞定位特性以及在二倍体和三倍体枇杷早晚花品种中的表达水平。采用花序浸染转化拟南芥,并利用实时荧光定量PCR分析转基因拟南芥植株的EjAGL6基因表达量,进一步观察野生型与EjAGL6转基因拟南芥的表型差异,分析EjAGL6基因的功能,为解析EjAGL6基因参与三倍体枇杷花期调控机制提供理论依据。结果显示：(1)成功获得MADS box基因EjAGL6;该基因的编码区序列(CDS)为732 bp,编码243个氨基酸,分子质量为27.88 kD,等电点为 9.05,脂溶指数为 79.05;系统进化树分析表明,枇杷EjAGL6与苹果MdAGL6蛋白质的相似性较高,聚在同一分支。(2)蛋白序列比对发现,EjAGL6的M区有57个氨基酸,I区有30个氨基酸,K区有82个氨基酸,C区有74个氨基酸,其中C区包含高度保守的AGL6基序Ⅰ和AGL6基序Ⅱ。(3)亚细胞定位分析表明,EjAGL6蛋白定位在细胞核,具有典型的MADS box转录因子亚细胞定位特性。(4)实时荧光定量PCR分析表明,EjAGL6基因在二倍体和三倍体枇杷早、晚花品种中均有表达,主要集中于小花分化期(S6)、花蕾露白期(S7)和盛花期(S8),且EjAGL6基因在二倍体和三倍体早花品种中的花蕾露白期的表达量均较高。(5) 转基因拟南芥株系的EjAGL6基因表达量显著高于野生型拟南芥;转EjAGL6基因植株表型观察显示,EjAGL6基因在拟南芥中过量表达能够使转EjAGL6基因拟南芥的开花时间提前1周左右。研究认为,EjAGL6基因可促使枇杷开花时间提前,推测EjAGL6基因在花蕾露白期发挥调控花期的关键作用。     

水母雪莲花青素合成相关基因的克隆及表达

为研究高山植物水母雪莲对强紫外辐射的分子适应机制,采用RT PCR结合RACE技术从水母雪莲中克隆了参与调控花青素合成的相关基因(SmMYB1),并采用hi TAIL PCR方法扩增了该基因的启动子序列。结果表明：(1)序列分析显示,SmMYB1基因cDNA序列(GenBank 登录号 MT188353)全长1 011 bp,编码269个氨基酸,gDNA序列含有2个内含子和3个外显子。(2)生物信息学分析显示,SmMYB1基因编码蛋白和菊科MYB蛋白亲缘关系最近,含有保守的［DE］Lx(2)［RK］ x(3)Lx(6)Lx(3)R和ANDV两个模体,属于拟南芥MYB第六亚族。SmMYB1基因启动子(GenBank 登录号 MT188354)全长1 407 bp,含有多个光响应元件。(3)荧光定量分析发现,SmMYB1基因在根、茎、叶和花中均表达,且在花中的表达量最高;在紫外胁迫下,SmMYB1基因的表达量在4 h达到最高,随后逐渐降低。研究推测SmMYB1基因可能参与调控水母雪莲花青素的合成以及对紫外辐射的响应过程。     

蒺藜苜蓿MtbHLH148转录因子的克隆与转化及其功能分析

bHLH(Basic helix loop helix, bHLH)转录因子家族是植物最大的转录因子家族之一,广泛参与植物生长发育和盐胁迫应答机制。该研究利用同源克隆的方法克隆蒺藜苜蓿(Medicago truncatula)的MtbHLH148基因,采用qRT PCR方法分析MtbHLH148基因在蒺藜苜蓿中的表达特性,构建超表达载体并通过农杆菌侵染法转化拟南芥(Arabidopsis thaliana),对转基因拟南芥的耐盐性相关功能进行分析研究。结果显示：(1)从蒺藜苜蓿中获得MtbHLH148基因,该基因cDNA全长1 343 bp,包含开放阅读框为603 bp,编码 201 个氨基酸,蛋白分子量22.7 kD,等电点为11.76;蛋白结构分析显示,该蛋白无跨膜结构域,无信号肽,为亲水性蛋白;含有精氨酸／赖氨酸残基的保守结构域和典型的bHLH结构域;二级结构以α 螺旋和无规则卷曲为主。(2)亚细胞定位表明,MtbHLH148蛋白定位在细胞核。(3)进化树分析表明,MtbHLH148与大豆(Glycine max)的亲缘性最近;启动子分析发现,该基因启动子区域含有光响应元件、MYB结合位点以及ABA应答元件ABRE,可能参与非生物胁迫。(4)qRT PCR分析发现,MtbHLH148基因在蒺藜苜蓿的茎中表达量最高,叶中表达量最低,且MtbHLH148基因受ABA(100 μmol/L)诱导并在盐胁迫(200 mmol/L NaCl)处理8 h内表达量上调,而在低温(4 ℃)处理时表达量明显下调。(5)成功构建超表达载体pCAMBIA3301 MtbHLH148并转化拟南芥获得16个抗性株系,经鉴定有12个过表达株系,其中表达量最高的转基因株系为OE8;对OE8株系耐盐性功能分析发现,转基因拟南芥植株的发芽率明显高于野生型,盐胁迫下转基因拟南芥的根长是野生型的1.5倍,表明其耐盐性得到了增强。研究表明,MtbHLH148基因可能在盐胁迫调节机制中具有一定的调控作用。     

中间锦鸡儿CiPUB22基因克隆与功能分析

中间锦鸡儿(Caragana intermedia)耐旱、耐寒、耐盐碱,是西北干旱地区的重要固沙灌木,筛选其优良抗逆境基因,可以作为林草基因工程的基因源。该研究在中间锦鸡儿干旱胁迫转录组文库中找到1条CiPUB22 (plant U box 22)基因的cDNA全长序列,CiPUB22基因包括1 260 bp开放阅读框,编码419个氨基酸。实时荧光定量PCR结果表明,在脱水、盐和ABA处理1 h后CiPUB22基因表达量上升并达到最高水平,分别为对照表达量的12倍、35倍和7倍,干旱处理后12 d达到最高值,为对照的2.5倍,表明CiPUB22的转录水平受非生物胁迫诱导。构建CiPUB22基因的过表达载体并转化野生型拟南芥,对转基因纯合体株系抗逆性分析发现,在150 mmol/L NaCl、1 μmol/L ABA和400 mmol/L甘露醇处理下,过表达株系的萌发率均低于野生型,说明过表达CiPUB22基因降低了拟南芥在种子萌发过程中对盐和渗透胁迫的耐受性。     

小麦盐华南象草PpCAD基因的亚细胞定位及其在转基因烟草中的异源表达迫相关基因的克隆与表达分析

该研究根据已克隆的华南象草(Pennisetum purpureum cv.Huanan)肉桂醇脱氢酶(CAD)基因PpCAD的cDNA序列,构建亚细胞定位载体pAN580-PpCAD,用PEG介导法转化象草原生质体,以探究PpCAD蛋白在细胞内的定位;同时构建植物过表达载体pBA002-PpCAD,通过农杆菌介导法在烟草中异源表达,以研究PpCAD基因与植物木质素合成的关系。结果显示:(1)PpCAD定位在象草原生质体的细胞质内;(2)过表达载体pBA002-PpCAD转化烟草后获得27株转基因烟草,其中25株PCR鉴定为阳性;(3)半定量RT-PCR检测6株转基因烟草后发现,PpCAD基因在不同植株的表达量存在差异,通过Southern杂交检测后发现该差异与目的基因插入的拷贝数有关;(4)6株转基因烟草和野生型烟草表型上没有明显差异,除目的基因多拷贝插入的植株OEC6外,木质素含量有不同程度的提高,最高比野生型提高了56.50%。研究表明,PpCAD是一个细胞质蛋白,在烟草中过表达PpCAD能够提高植株木质素含量,表明PpCAD基因参与了植物的木质素合成,可用于象草的木质素调控研究。     

Effects of MULTIFOLIATE-PINNA, AFILA, TENDRIL-LESS and UNIFOLIATA genes on leafblade architecture in Pisum sativum

In order to dissect the genetic regulation of leafblade morphogenesis, 16 genotypes of pea, constructed by combining the wild-type and mutant alleles of MFP, AF, TL and UNI genes, were quantitatively phenotyped. The morphological features of the three domains of leafblades of four genotypes, unknown earlier, were described. All the genotypes were found to differ in leafblade morphology. It was evident that MFP and TL functions acted as repressor of pinna ramification, in the distal domain. These functions, with and without interaction with UNI, also repressed the ramification of proximal pinnae in the absence of AF function. The expression of MFP and TL required UNI function. AF function was found to control leafblade architecture multifariously. The earlier identified role of AF as a repressor of UNI in the proximal domain was confirmed. Negative control of AF on the UNI-dependent pinna ramification in the distal domain was revealed. It was found that AF establishes a boundary between proximal and distal domains and activates formation of leaflet pinnae in the proximal domain.     

Presence of Rhizobium Etli bv . Phaseoli and Rhizobium Gallicum bv . Gallicum in Egyptian Soils

Seven bean rhizobial strains EBRI 2, 3, 21, 24, 26, 27 and 29 identified as Rhizobium etli, and EBRI 32 identified as Rhizobium gallicum, isolated from Egyptian soils and which nodulated Phaseolus vulgaris efficiently, were subjected to hybridization with a nifH probe in order to estimate the copy number of this gene. Seven strains (EBRI 2, 3, 21, 24, 26, 27 and 29) which were only able to nodulate Phaseolus vulgaris, contained three copies of the nifH gene, consistent with their identification as Rhizobium etli bv. phaseoli. Only one strain (EBRI 32) which nodulated both Phaseolus vulgaris and Leucaena leucocephala, had one copy of nifH gene. This confirmed the classification of this strain as Rhizobium gallicum bv. gallicum.     

Prosthecium species with Stegonsporium anamorphs on Acer

Data from microscopic morphology, single-spore cultures, and DNA analyses of teleomorphs and anamorphs support the recognition of five species of Prosthecium with Stegonsporium anamorphs on Acer: P. acerinum sp. nov., the teleomorph of S. acerinum; P. acerophilum comb. nov., formerly known as Dictyoporthe acerophila; P. galeatum comb. nov., originally described as Massaria galeata; P. opalus sp. nov.; and P. pyriforme sp. nov., the teleomorph of S. pyriforme s. str. The morphology of both type specimens and freshly collected material was investigated. The teleomorphs have brown ellipsoidal ascospores with five distosepta and often a longitudinal distoseptum. The anamorphs of all species described here belong to Stegonsporium; their connection to the Prosthecium teleomorphs was demonstrated by morphology and DNA sequences of single spore cultures derived from both ascospores and conidia. The anamorphs and teleomorphs of all five Prosthecium species are described and illustrated by LM images, and a key to these species is provided. As perceived from this work, S. pyriforme is restricted to Europe and does not occur in North America, whereas S. acerinum is restricted to North America, not found in Europe. The host associations given in the literature are revised and evidence is provided that only A. opalus, A. pseudoplatanus, and A. saccharum are confirmed hosts of Prosthecium with Stegonsporium anamorphs. Molecular phylogenetic analyses of tef1, ITS rDNA, and partial nuLSU rDNA sequences confirm that the species with Stegonsporium anamorphs are closely related to P. ellipsosporum, the generic type species. Stilbospora macrosperma is confirmed as the anamorph of P. ellipsosporum by DNA data of single spore isolates obtained from both ascospores and conidia.     

Characterisation of cell wall polysaccharides, arabinogalactans-proteins (AGPs) and phenolics of Cola nitida, Cola acuminata and Garcinia kola seeds

Many Cola plant species are endemic to West and Central Africa. Cola acuminata and Cola nitida are used as masticatory when fresh, while the dried nuts are used for beverages and pharmaceutical purposes in Europe and North America. Garcinia kola seeds, that serve as a substitute for the true kola nuts, are used in African traditional medicine for the treatment of various diseases, including colic, headache and liver cirrhosis. Seeds extracts of G. kola are also known for their anti-inflammatory, antimicrobial and antiviral properties. To gain information on the chemical properties of the kolas, we have isolated and analyzed cell wall polysaccharides, arabinogalactan-proteins and phenolic substances from the seeds of the three kola species. The sugar composition of cell wall material of C. acuminata, C. nitida and G. kola revealed that Gal (up to 30%), Ara, GalA and Glc as the predominant monosaccharides, representing approximately 90% by mol of the total hydrolysable sugar present in this material. In Ammonium oxalate cell wall fraction, GalA was found to be the major sugar present in all kola species. In the alkali-soluble fraction, there were significant differences in the level of Glc and Gal. The level of Glc was high in C. acuminata and C. nitida while the level of Gal and Xyl were high in C. nitida and G. cola. Isolation and quantification of arabinogalactan-proteins demonstrate that G. kola seeds contained four to eight times more of these proteoglycans than the seeds of the other two species. Finally, analysis of soluble phenolic substances shows that caffeine and catechin were largely represented in C. acumina and C. nitida seeds, with caffeine accounting for 50% of all soluble phenolics. These findings indicate that the three Kola seeds are highly enriched in pectins and proteoglycans and that C. acuminata and C. nitida can be used as a possible source of caffeine and catechin.     

中国黑粉菌属和利罗黑粉菌属

黑粉菌属是Roussel 1806年建立的,全世界记载有三百余种,主要寄生于禾本科,是经济作物及牧草的重要致病菌·长期以来,对黑粉菌的邢子使用过各种名称,如厚垣孢子,冬孢子及黑粉孢子等.本文采用黑粉孢子以区别锈菌的冬孢子. 芳’(1979)在《中国真菌总汇》中列出黑粉菌属五十种及一个变型.作者经过显微结构和超显微结构的研究,承认其中二十九种为正确名称,八种及一变型为异名,顶黑粉菌(Ustilago acrearus Berk.)由于错拼而被废弃.埃地黑粉菌(Ustilago emodensis Berk.)被转移至利罗粉菌属(Liroa).另有十一种黑粉菌因缺少标本留待今后订正.自1979年以后,杨信东(1983)增加黑粉菌属二种我国新纪录,K.范基和郭林(1986)描述一新种,四种新纪录.在本文中,作者描述一新种:鸢尾蒜黑粉(Ustilago ixiolirii Guo L) ,孢子堆生在蒴果内,不开裂,黑色,粉末状.黑粉孢子球形,近球形,稀椭圆形, 12.5-21×10-21μm,黑褐色,壁厚1-1.Sμm,纹饰脑状.是迄今生在石蒜科植物上唯一黑粉菌的种,其它几种黑粉菌均属条黑粉菌属.本文增加七种我国新纪录.共计四十九种,寄生于六科四十四属植物,主要是禾本科和蓼科.这仅是黑粉菌属研究的初步报告,在全国范围内大量采集黑粉菌标本后,作者相信会有更多新种和我国新纪录被发现.利罗黑粉菌属(Liroa)是从黑粉菌属(Ustaligo)分出的,此属为单种属.     

Comparative study of Bifidobacteriumanimalis, Escherichiacoli, Lactobacilluscasei and Saccharomycesboulardii probiotic properties

The present work investigates some probiotic properties of four different microorganisms (Bifidobacterium animalis var. lactis BB-12, Escherichia coli EMO, Lactobacillus casei and Saccharomyces boulardii). In vitro and in vivo tests were carried out to compare cell wall hydrophobicity, production of antagonistic substances, survival capacity in the gastrointestinal tract of germ-free mice without pathological consequence, and immune modulation by stimulation of Küpffer cells, intestinal sIgA and IL-10 levels. In vitro antagonism against pathogenic bacteria and yeast was only observed for the probiotic bacteria B. animalis and L. casei. The hydrophobic property of the cell wall was higher for B. animalis and E. coli EMO, and this property could be responsible for a better ability to colonize the gastrointestinal tract of germ-free mice. Higher levels of sIgA were observed mainly for S. boulardii, followed by E. coli EMO and B. animalis, and only S. boulardii induced a significant higher level of IL-10. In conclusion, for a probiotic use, S. boulardii presented better characteristics in terms of immunomodulation, and B. animalis and L. casei for antagonistic substance production. The knowledge of the different probiotic properties could be used to choice the better microorganism depending on the therapeutic or prophylactic application.     

Probing the Drosophila retinal determination gene network in Tribolium (II): The Pax6 genes eyeless and twin of eyeless

The Pax6 genes eyeless (ey) and twin of eyeless (toy) are upstream regulators in the retinal determination gene network (RDGN), which instructs the formation of the adult eye primordium in Drosophila. Most animals possess a singleton Pax6 ortholog, but the dependence of eye development on Pax6 is widely conserved. A rare exception is given by the larval eyes of Drosophila, which develop independently of ey and toy. To obtain insight into the origin of differential larval and adult eye regulation, we studied the function of toy and ey in the red flour beetle Tribolium castaneum. We find that single and combinatorial knockdown of toy and ey affect larval eye development strongly but adult eye development only mildly in this primitive hemimetabolous species. Compound eye-loss, however, was provoked when ey and toy were RNAi-silenced in combination with the early retinal gene dachshund (dac). We propose that these data reflect a role of Pax6 during regional specification in the developing head and that the subsequent maintenance and growth of the adult eye primordium is regulated partly by redundant and partly by specific functions of toy, ey and dac in Tribolium. The results from embryonic knockdown and comparative protein sequence analysis lead us further to conclude that Tribolium represents an ancestral state of redundant control by ey and toy.     

Doc and copia instability in an isogenic Drosophila melanogaster stock

A high degree of heterogeneity and an overall increase in number of insertion sites of the mobile elements Doc and copia were revealed in one substock of an isogenic Drosophila melanogaster stock, while in two other substocks the distribution of copia sites was highly homogenous, but that of Doc sites was again heterogenous. We therefore concluded that copia was unstable in one of the substocks and Doc was unstable in all. Doc instability presumably arose earlier than copia instability. Doc and copia transpositions were directly observed in experiments with one substock. An abundance of copia insertions was revealed in the X chromosome where insertions with deleterious effects are exposed to selection in hemizygous condition. The locations of many other mobile elements (mdg1, mdg2, mdg3, mdg4, 297, B104, H.M.S. Beagle, I, P, BS, FB) were found to be conserved in each substock and did not differ between them, indicating that these mobile elements were stable. This homogeneity is a strong argument against any possibility of inadvertent contamination.