科技翻译论文

Sensing Human Activity:GPS Tracking感应人类活动:GPS跟踪Stefan van der Spek1,*,Jeroen van Schaick1,Peter de Bois1,2and Remco de Haan1Abstract:The enhancement of GPS technology enables the use of GPS devices not only as navigation and orientation tools,but also as instruments used to capture travelled routes:assensors that measure activity on a city scale or the regional scale.TU Delft developed aprocess and database architecture for collecting data on pedestrian movement in threeEuropean city centres,Norwich,Rouen and Koblenz,and in another experiment forcollecting activity data of13families in Almere(The Netherlands)for one week.Thequestion posed in this paper is:what is the value of GPS as‘sensor technology’measuringactivities of people?The conclusion is that GPS offers a widely useable instrument tocollect invaluable spatial-temporal data on different scales and in different settings addingnew layers of knowledge to urban studies,but the use of GPS-technology and deploymentof GPS-devices still offers significant challenges for future research.摘要：增强GPS技术支持使用GPS设备不仅作为导航和定位工具,但也为仪器用来捕捉旅行路线:作为传感器,测量活动在一个城市或区域范围内规模。

机器翻译技术论文机器翻译是使用计算机实现一种自然语言文本到另一种自然语言文本的翻译。

下面是店铺整理的机器翻译技术论文，希望你能从中得到感悟!机器翻译技术论文篇一机器翻译在翻译实践中的应用摘要: 本文研究机器翻译在翻译实践中的应用,其由两部分组成:第一部分概述机器翻译,第二部分通过一个具体的翻译任务演示谷歌翻译工具的用法。

关键词: 机器翻译谷歌翻译译后编辑一、机器翻译概述机器翻译是指将翻译过程的部分或全部使用机器实现自动化(Austermühl,2006)。

一般认为机器翻译的思想起源于1949年写作的韦弗备忘录,而后机器翻译的发展经历了重大的起伏。

时至今日,机器翻译的研究和产品如雨后春笋般不断涌现出来,机器翻译已然成为一个具有重大社会意义、政治意义、商业价值、科学价值和哲学意义的重要课题。

机器翻译系统可以依据不同的标准分为不同的种类。

根据机器翻译系统的使用环境可以分为三类:低端机器翻译系统、用户定制的高端机器翻译系统和基于因特网的机器翻译系统。

低端机器翻译系统的目标客户是个人,用户定制的高端机器翻译系统的目标客户是公司,基于因特网的机器翻译系统则是一种通过因特网使用的。

根据机器翻译系统使用的技术可以分为下图所示的五类:基于规则的机器翻译系统、基于语料库的机器翻译系统、多引擎机器翻译系统、在线机器翻译系统和口语机器翻译系统(Feng,2004)。

一般而言,由于自然语言中诸如歧义、复杂句法、成语和照应关系之类问题,机器翻译的输出结果并不能令用户满意。

于是一些人认为机器翻译系统对于译员而言毫无用处。

我认为这是一种误解。

翻译的过程一般可以分为两个阶段:第一阶段是翻译出译稿,第二阶段是修改译稿以求译文可以达到要求。

在多数情况下使用机器翻译的目的仅仅是将第一阶段自动化,即翻译出译稿。

然后由译员修改译稿,最终产出达到要求的译文。

由此可见,机器翻译在将文本翻译成译稿的过程中大有用处。

在使用机器翻译将文本翻译成译稿的过程中,我们还可以使用多种方法提高机器翻译输出结果的质量。

人工智能对翻译的影响论文在当今这个信息技术飞速发展的时代，人工智能（AI）已经成为推动社会进步和科技创新的重要力量。

特别是在语言翻译领域，人工智能的应用正日益深入，对翻译行业产生了深远的影响。

本文将探讨人工智能对翻译的影响，分析其优势与挑战，并展望其未来的发展趋势。

引言翻译作为跨文化交流的桥梁，历来是国际交流中不可或缺的一部分。

随着全球化的不断深入，翻译需求日益增长，传统的翻译方式已经难以满足现代社会的需求。

人工智能技术的引入，为翻译行业带来了革命性的变化。

通过机器学习、自然语言处理等技术，人工智能翻译系统能够实现快速、准确的语言转换，极大地提高了翻译效率。

人工智能翻译技术的发展人工智能翻译技术的发展经历了从早期的基于规则的翻译系统到现代基于统计和神经网络的翻译系统。

早期的翻译系统依赖于语言学家制定的规则，这些规则虽然在一定程度上能够实现语言的转换，但往往缺乏灵活性和准确性。

随着大数据和计算能力的提升，基于统计的翻译系统开始兴起，它们通过分析大量的双语文本数据，学习语言之间的对应关系，从而实现更加准确的翻译。

近年来，神经网络翻译（NMT）技术的出现，更是将翻译质量推向了一个新的高度。

NMT利用深度学习技术，模拟人脑的神经网络结构，能够更好地理解语言的语义和语境，提供更加自然流畅的翻译结果。

人工智能翻译的优势1. 高效率：人工智能翻译系统能够在短时间内处理大量文本，显著提高翻译速度。

2. 低成本：与传统人工翻译相比，AI翻译减少了人力成本，降低了翻译费用。

3. 可定制性：AI翻译系统可以根据用户需求进行定制，满足不同领域的专业翻译需求。

4. 持续学习：AI翻译系统具备自我学习和优化的能力，随着使用时间的增长，翻译质量会不断提升。

人工智能翻译面临的挑战尽管人工智能翻译技术取得了显著进展，但它仍然面临着一些挑战：1. 语言的复杂性：语言不仅仅是文字的组合，还包含了丰富的文化和情感色彩，AI翻译系统在理解和表达这些细微差别方面还有待提高。

讯飞论文翻译去年11月，谷歌在美国发布了无线耳机Pixel Buds，凭借着实时翻译的功能，成功吸晴。

由于它支持40种语音，甚至可以被当作是一台简单的翻译机。

需要配合Pixel手机才能支持。

并不是安卓手机通用。

其实我们在惊叹谷歌高科技的时候，国内在语音识别领域的佼佼者，科大讯飞在年初的发布了自己的智能翻译机——译呗实时翻译机，基于科大讯飞核心口语翻译技术，能够快速准确地实现中对多语口语间的即时互译。

看着像个旧时代的小灵通，但内里却是新时代的高科技！在衣食住行等日常生活领域，晓译翻译机已经达到了大学英语六级水平，不论是学习、工作、出国旅行，它都能做你口袋里的便携翻译官！也可以是你的贴身外教！科大讯飞晓译翻译机搭载了国际领先的语音合成、语音识别、口语翻译引擎，以大量日常对话内容为翻译基础，对时下热词新词进行及时更新，并按照平时说话的方式翻译出来，准确率达到97%。

科大讯飞译呗翻译机体型小巧，比iPhone手机还小。

带上它无需导游，中文进出来英文，英文进出来中文，就可以与外国朋友沟通。

并通过自带专属APP与Wi-Fi网络或手机热点进行绑定，以匹配海量云端资源，拥有超过4000万条平行语句，基本覆盖了日常生活、旅游出差等各个场景。

翻译的同时，由于是通过热点和wifi与手机链接，科大讯飞译呗翻译机迅即就可以将双方的对话记录通过APP记录并显示出来。

如此一来，这就是一个随身的语音速记员。

你就不用担心遗漏重要内容了。

有了如此人工智能的基础，无论是在国内还是国外，想与人时时进行沟通，还是自学使用，还是娱乐搜索它都可以轻松面对。

集同声互译、学习、娱乐多种功能于一身，是一款真正的随身便携翻译器，有了它，你还学英语干嘛？。

科技英语翻译与功能对等理论论文摘要：风格层面的功能对等主要体现在科技英语的语篇是否突出了层次的清晰、构思的严谨、措辞的简洁以及重点表达的思想等四个方面的特点，这四个特点也是科技英语翻译在翻译过程中应该遵循的基本原则和重要规范。

一、功能等理论概述功能对等理论是美国语言学家和翻译家尤金·奈达在1964年出版的《翻译科学初探》中提出来的，他提出了“形式对等”和“动态对等”两个翻译概念，其中“形式对等”是指翻译的过程中将原文的含义和特征原封不动地进行直译的翻译，或者接复制至目的文本中；而“动态对等”是翻译中用最贴切的对等语再现原来的信息，达到从语义到语体的过程。

奈达认为“形式对等”与“动态对等”的最大区别在于翻译的接受语所达到的效果，他对“动态对等”做了强调，并在此基础上提出了具有影响力的功能对等，并根据对等的程度对功能对等做了不同层次的划分，属于最高层次的功能对等是读者通过阅读译文所体会到的感想与原文的读者读到原文时所感受到的体会是一致的，这是最理想的翻译的境界。

最低层次的功能对等是实现译文读者的对原文的想象，即译文读者通过阅读译文能够想象到原文读者对原文欣赏时的心理体验，这是阅读译文最基本的要求。

功能对等理论的核心是译文读者对译文的反映，直译与意译一直是存在于翻译中具有争论的两个方面，其争论的焦点在于译文与原文之间的关系，直译要求要尊重原文，准确地翻译原文；而意译要求将原文理解后以便于读者接受的语言翻译出来。

由于原文的读者与译文的读者在接受信息方面存在一定的差异，因此，要达到原文与译文之间的真正对等是不可能的，奈达的对等功能强调的是相对意义的对等，在翻译的实践中要以语言的差异进行灵活地翻译，可以和原文有一定的出入，但是，翻译的本质还是对文本信息内涵的传递，通过相对的对等，可以避免翻译过程中一些过分关注原文而造成译文难以理解的缺陷。

二、科技英语特点及分类科技英语是指在自然科学以及工程技术方面所使用的英语，包括涉及的教科书、著作以及论文和报告等，从广义上来讲，科技英语就是所有与科学有关的英语。

英语科技论文长句翻译中的常见问题和处理技巧英汉双语思维方式及语言表达习惯的不同增加了翻译的难度，特别是长句的翻译一直是英译汉中的重点和难点。

在英语科技论文翻译中，蓝译编译认为，翻译长句的过程可分为两个阶段：一是拆句即分析源语句子结构、理解内容；二是组句即整理源语句中的信息点、用目标语重新表达。

翻译实践中发现，在这两个阶段中最常见的问题，是语序问题和断句的问题。

一、语序问题的处理技巧。

英语的修饰成分多、长度长，而且多位于中心词的后面，但在汉语中定语和状语长度短，往往位于中心词之前。

翻译时就有必要对这些附属结构的顺序进行变动，维持原句的顺序肯定是不符合汉语表达习惯的。

译者要灵活运用常见的长句翻译方法，特别是综合使用顺译法和逆译法，把握信息点的重要性，考虑英汉排列信息的特点，按照各自的语言表达习惯重新排列信息。

一般来说，英语句子注重信息的主次之分，主要信息放在突出位置，次要信息作为辅助性的描写或叙述手段。

同时，英语有时态，可以通过动词的变化显出动作发生的先后顺序，而且英语大量使用分词和从句，位置也灵活，可前可后。

相比之下，汉语简单一些，叙事多借助并列结构即并列分句和并列谓语，按照时间顺序和逻辑顺序排列各成分的顺序。

汉语的信息重心并不在于形式，而体现在内在逻辑关系上。

二、断句的问题的处理技巧。

汉语多流水句，一个长句可能有多个主语，而英语中一句话只能有一个主语，因此有些情况下需要把长句断开翻译。

原文里的一句话在译文时可能分成两句或多句，尤其是在并列句中如果内容具有同等的重要性，或是相互间的关系不那么密切，往往可以分割开来。

译者首先要确定句子主干，确定原句的时态、语态、语气，从整体上把握句子结构。

然后区分主(句)从(句)，识别修饰语。

在第一步确定整个句子的中心内容的基础上分析各个分层的意思，判断分析各成分的内在逻辑关系和各自功能，搞清整个长句的层次，推断句子思维逻辑和表达重心。

分析清楚长句结构后，关键一点就是在何处断句，具体要把握以下原则：在结论、结果前断句；在句子语气变化处断开；在反问句、感叹句等句式变化处断开；在句子信息由总向分或者由分向总处断开；在分句顺序变化处断开。

LOGO第一章记叙文体的英译与写作第二章法律文体的英译与写作第三章应用文体英译与写作第四章广告文体英译与写作QQ:105448245424学时科技英语(二)EST ⅡREFERENCES:1、张梦井，杜耀文汉英科技翻译指南，航空工业出版社，19962、王运，实用科技英语翻译技巧，科技文献出版社，19923、熊第霖，英文科技写作，国防工业出版社，20011 记叙文体的汉译英1. 1 科技论文的汉译英问题1. 2 摘要的英译与写作1. 3 国际会议文献的英译与写作1. 1 科技论文的汉译英问题一、科技论文的分类◆按学科的性质和功能⏹基础学科论文⏹技术学科论文⏹应用学科论文◆按照写作目的和发挥的作用⏹学术性论文⏹技术性论文⏹学位论文◆按论文内容所属学科数学论文物理论文化学论文天文学论文机械工程技术论文建筑工程技术论文◆按研究和写作方法理论推导型实(试)验研究型观测型设计计算型发现发明型争鸣型综述型Title标题Abstract摘要Keywords关键词Table of contents目录Nomenclature术语表Introduction引言正文Acknowledgement致谢Reference参考文献Appendix附录Methods方法Results结果Discussion讨论Conclusion结论二、科技论文的一般结构LOGOacknowledgmentReferencesTitle 标题Author 作者Abstract 摘要Introduction 引言4 Summary and conclusion三、论文标题的英译与写作1、标题的作用⏹Generalizing the Text⏹Attracting the Reader⏹Facilitating the Retrieval2、标题的长度（单词总数）及词性⏹标题不宜过长，大多为12个单词以内。

⏹标题中用得最多的是名词（包括动名词），除名词外，用得较多的是介词，有时使用形容词、冠词、连词、副词。

生物科学论文中英文资料外文翻译文献Carotenoid Biosynthetic Pathway in the Citrus Genus: Number of Copies and Phylogenetic Diversity of Seven GeneThe first objective of this paper was to analyze the potential role of allelic variability of carotenoid biosynthetic genes in the interspecifi diversity in carotenoid composition of Citrus juices. The second objective was to determine the number of copies for each of these genes. Seven carotenoid biosynthetic genes were analyzed using restriction fragment length polymorphism (RFLP) and simple sequence repeats (SSR) markers. RFLP analyses were performed with the genomic DNA obtained from 25 Citrus genotypes using several restriction enzymes. cDNA fragments of Psy, Pds, Zds, Lcyb, Lcy-e, Hy-b, and Zep genes labeled with [R-32P]dCTP were used as probes. For SSR analyses, two primer pairs amplifying two SSR sequences identified from expressed sequence tags (ESTs) of Lcy-b and Hy-b genes were designed. The number of copies of the seven genes ranged from one for Lcy-b to three for Zds. The genetic diversity revealed by RFLP and SSR profiles was in agreement with the genetic diversity obtained from neutral molecμLar markers. Genetic interpretation of RFLP and SSR profiles of four genes (Psy1, Pds1, Lcy-b, and Lcy-e1) enabled us to make inferences on the phylogenetic origin of alleles for the major commercial citrus species. Moreover, the resμLts of our analyses suggest that the allelic diversity observed at the locus of both of lycopene cyclase genes, Lcy-b and Lcy-e1, is associated with interspecific diversity in carotenoid accumμLation in Citrus. The interspecific differences in carotenoid contents previously reported to be associated withother key steps catalyzed by PSY, HY-b, and ZEP were not linked to specific alleles at the corresponding loci.KEYWORDS: Citrus; carotenoids; biosynthetic genes; allelic variability; phylogeny INTRODUCTIONCarotenoids are pigments common to all photosynthetic organisms. In pigment-protein complexes, they act as light sensors for photosynthesis but also prevent photo-oxidat ion induced by too strong light intensities. In horticμLtural crops, they play a major role in fruit, root, or tuber coloration and in nutritional quality. Indeed some of these micronutrients are precursors of vitamin A, an essential component of human and animal diets. Carotenoids may also play a role in chronic disease prevention (such as certain cancers), probably due to their antioxidant properties. The carotenoid biosynthetic pathway is now well established. Carotenoids are synthesized in plastids by nuclear-encoded enzymes. The immediate precursor of carotenoids (and also of gibberellins, plastoquinone, chlorophylls,phylloquinones, and tocopherols) is geranylgeranyl diphosphate (GGPP). In light-grown plants, GGPP is mainly derivedcarotenoid, 15-cis-phytoene. Phytoene undergoes four desaturation reactions catalyzed by two enzymes, phytoene desaturase (PDS) and β-carotene desaturase (ZDS), which convert phytoene into the red-colored poly-cis-lycopene. Recently, Isaacson et al. and Park et al. isolated from tomato and Arabidopsis thaliana, respectively, the genes that encode the carotenoid isomerase (CRTISO) which, in turn, catalyzes the isomerization of poly-cis-carotenoids into all-trans-carotenoids. CRTISO acts on prolycopene to form all-trans lycopene, which undergoes cyclization reactions. Cyclization of lycopene is abranching point: one branch leads to β-carotene (β, β-carotene) and the other toα-carotene (β, ε-carotene). Lycopene β-cyclase (LCY-b) then converts lycopene intoβ-carotene in two steps, whereas the formation of α-carotene requires the action of two enzymes, lycopene ε- cyclase (LCY-e) and lycopene β-cyclase (LCY-b). α- carotene is converted into lutein by hydroxylations catalyzed by ε-carotene hydroxylase (HY-e) andβ-carotene hydroxylase (HY-b). Other xanthophylls are produced fromβ-carotene with hydroxylation reactions catalyzed by HY-b and epoxydation catalyzed by zeaxanthin epoxidase (ZEP). Most of the carotenoid biosynthetic genes have been cloned and sequenced in Citrus varieties . However, our knowledge of the complex regμLation of carotenoid biosynthesis in Citrus fruit is still limited. We need further information on the number of copies of these genes and on their allelic diversity in Citrus because these can influence carotenoid composition within the Citrus genus.Citrus fruit are among the richest sources of carotenoids. The fruit generally display a complex carotenoid structure, and 115 different carotenoids have been identified in Citrus fruit. The carotenoid richness of Citrus flesh depends on environmental conditions, particμLarly on growing conditions and on geogr aphical origin . However the main factor influencing variability of caro tenoid quality in juice has been shown to be genetic diversity. Kato et al. showed that mandarin and orange juices accumμLated high levels of β-cryptoxanthin and violaxanthin, respectively, whereas mature lemon accumμLated extremely low levels of carotenoids. Goodner et al. demonstrated that mandarins, oranges, and their hybrids coμLd be clearly distinguished by theirβ-cryptoxanthin contents. Juices of red grapefruit contained two major carotenoids: lycopene and β-carotene. More recently, we conducted a broad study on the organization of the variability of carotenoid contents in different cμLtivated Citrus species in relation with the biosynthetic pathway . Qualitative analysis of presence or absence of the different compounds revealed three main clusters: (1) mandarins, sweet oranges, and sour oranges;(2) citrons, lemons, and limes; (3) pummelos and grapefruit. Our study also enabled identification of key steps in the diversification of the carotenoid profile. Synthesis of phytoene appeared as a limiti ng step for acid Citrus, while formation of β-carotene and R-carotene from lycopene were dramatically limited in cluster 3 (pummelos and grapefruit). Only varieties in cluster 1 were able to produce violaxanthin. In the same study , we concluded that there was a very strong correlation between the classification of Citrus species based on the presence or absence of carotenoids (below,this classification is also referred to as the organization of carotenoid diversity) and genetic diversity evaluated with bi ochemical or molecμLar markers such as isozymes or randomLy amplified polymorphic DNA (RAPD). We also concluded that, at the interspecific level, the organization of the diversity of carotenoid composition was linked to the global evolution process of cμLt ivated Citrus rather than to more recent mutation events or human selection processes. Indeed, at interspecific level, a correlation between phenotypic variability and genetic diversity is common and is generally associated with generalized gametic is common and is generally associated with generalized gametic disequilibrium resμLting from the history of cμLtivated Citrus. Thus from numerical taxonomy based on morphologicaltraits or from analysis of molecμLar markers , all authors agreed on the existence o f three basic taxa (C. reticμLata, mandarins; C. medica, citrons; and C. maxima, pummelos) whose differentiation was the resμLt of allopatric evolution. All other cμLtivated Citrus specie s (C. sinensis, sweet oranges; C. aurantium, sour oranges;C. paradi si, grapefruit; and C. limon, lemons) resμLted from hybridization events within this basic pool except for C. aurantifolia, which may be a hybrid between C. medica and C. micrantha .Our p revious resμLts and data on Citrus evolution lead us to propose the hypothesis that the allelic variability supporting the organization of carotenoid diversity at interspecific level preceded events that resμLted in the creation of secondary species. Such molecμLar variability may have two different effects: on the one hand, non-silent substitutions in coding region affect the specific activity of corresponding enzymes of the biosynthetic pathway, and on the other hand, variations in untranslated regions affect transcriptional or post-transcriptional mechanisms.There is no available data on the allelic diversity of Citrus genes of the carotenoid biosynthetic pathway. The objective of this paper was to test the hypothesis that allelic variability of these genes partially determines phenotypic variability at the interspecific level. For this purpose, we analyzed the RFLPs around seven genes of the biosynthetic pathway of carotenoids (Psy, Pds, Zds, Lcy-b, Lcy-e, Hy-b, Zep) and the polymorphism of two SSR sequences found in Lcy-b and Hy-b genes in a representative set of varieties of the Citrus genus already analyzed for carotenoid constitution. Our study aimed to answer the following questions: (a) are those genes mono- or mμLtilocus, (b) is the polymorphism revealed by RFLP and SSR markers inagreement with the general histor y of cμLtivated Citrus thus permitting inferences about the phylogenetic origin of genes of the secondary species, and (c) is this polymorphism associated with phenotypic (carotenoid compound) variations.RESΜLTS AND DISCUSSIONGlobal Diversity of the Genotype Sample Observed by RFLP Analysis. RFLP analyses were performed using probes defined from expressed sequences of seven major genes of the carotenoid biosynthetic pathway . One or two restriction enzymes were used for each gene. None of these enzymes cut the cDNA probe sequence except HindIII for the Lcy-e gene. Intronic sequences and restriction sites on genomic sequences werescreened with PCR amplification using genomic DNA as template and with digestion of PCR products. The resμLts indicated the absence of an intronic sequence for Psy and Lcy-b fragments. The absence of intron in these two fragments was checked by cloning and sequencing corresponding genomic sequences (data not shown). Conversely, we found introns in Pds, Zds, Hy-b, Zep, and Lcy-e genomic sequences corresponding to RFLP probes. EcoRV did not cut the genomic sequences of Pds, Zds, Hy-b, Zep, and Lcy-e. In the same way, no BamHI restriction site was found in the genomic sequences of Pds, Zds, and Hy-b. Data relative to the diversity observed for the different genes are presented in Table 4. A total of 58 fragments were identified, six of them being monomorphic (present in all individuals). In the limited sample of the three basic taxa, only eight bands out of 58 coμLd not be observed. In the basic taxa, the mean number of bands per genotype observed was 24.7, 24.7, and 17 for C. reticμLata, C. maxima, and C. medica, respectively. It varies from28 (C. limettioides) to 36 (C. aurantium) for the secondary species. The mean number of RFLP bands per individual was lower for basic taxa than for the group of secondary species. This resμLt indicates that secondary species are much more heterozygous than the basic ones for these genes, which is logical if we assume that the secondary species arise from hybridizations between the three basic taxa. Moreover C. medica appears to be the least heterozygous taxon for RFLP around the genes of the carotenoid biosynthetic pathway, as already shown with isozymes, RAPD, and SSR markers.The two lemons were close to the acid Citrus cluster and the three sour oranges close to the mandarins/sweet oranges cluster. This organization of genetic diversity based on the RFLP profiles obtained with seven genes of the carotenoid pathway is very similar to that previously obtained with neutral molecμLar markers such as genomic SSR as well as the organization obtained with qualitative carotenoid compositions. All these resμLts suggest that the observed RFLP and SSR fragments are good phylogenetic markers. It seems consistent with our basic hypothesis that major differentiation in the genes involved in the carotenoid biosynthetic pathway preceded the creation of the secondary hybrid species and thus that the allelic structure of these hybrid species can be reconstructed from alleles observed in the three basic taxa.Gene by Gene Analysis: The Psy Gene. For the Psy probe combined with EcoRV or BamHI restriction enzymes, five bands were identified for the two enzymes, and two to three bands were observed for each genotype. One of these bands was present in all individuals. There was no restriction site in the probe sequence. These resμLts lead us to believe that Psy is present at two loci,one where no polymorphism was found with the restriction enzymes used, and one that displayed polymorphism. The number of different profiles observed was six and four with EcoRV and BamHI, respectively, for a total of 10 different profiles among the 25 individuals .Two Psy genes have also been found in tomato, tobacco, maize, and rice . Conversely, only one Psy gene has been found in Arabidopsis thaliana and in pepper (Capsicum annuum), which also accumμLates carotenoids in fruit. According to Bartley and Scolnik, Psy1 was expressed in tomato fruit chromoplasts, while Psy2 was specific to leaf tissue. In the same way, in Poaceae (maize, rice), Gallagher et al. found that Psy gene was duplicated and that Psy1 and notPsy2 transcripts in endosperm correlated with endosperm carotenoid accumμLation. These resμLts underline the role of gene duplication and the importance of tissue-specific phytoene synthase in the regμLation of carotenoid accumμLation.All the polymorphic bands were present in the sample of the basic taxon genomes. Assuming the hypothesis that all these bands describe the polymorphism at the same locus for the Psy gene, we can conclude that we found allelic differentiation between the three basic taxa with three alleles for C. reticμLata, four for C. maxima, and one for C. medica.The alleles observed for the basic taxa then enabled us to determine the genotypes of all the other species. The presumed genotypes for the Psy polymorphic locus are given in Table 7. Sweet oranges and grapefruit were heterozygous with one mandarin and one pummelo allele. Sour oranges were heterozygous; they shared the same mandarin allele with sweet oranges but had a different pummelo allele. Clementine was heterozygous with two mandarin alleles; one shared with sweetoranges and one with “Willow leaf” mandarin. “Meyer” lemon was heterozygous, with the mandarin allele also found in sweet oranges, and the citron allele. “Eureka”lemon was also heterozygous with the same pummelo allele as sour oranges and the citron allele. The other acid Citrus were homozygous for the citron allele.The Pds Gen. For the Pds probe combined with EcoRV, six different fragments were observed. One was common to all individuals. The number of fragments per individual was two or three. ResμLts for Pds led us to believe that this gene is present at two loci, one where no polymorphism was found with EcoRV restriction, and one displaying polymorphism. Conversely, studies on Arabidopsis, tomato, maize, and rice showed that Pds was a single copy gene. However, a previous study on Citrus suggests that Pds is present as a low-copy gene family in the Citrus genome, which is in agreement with our findings.The Zds Gene. The Zds profiles were complex. Nine and five fragments were observed with EcoRV and BamHI restriction, respectively. For both enzymes, one fragment was common to all individuals. The number of fragments per individual ranged from two to six for EcoRV and three to five for BamHI. There was no restriction site in the probe sequence. It can be assumed that several copies (at least three) of the Zds gene are present in the Citrus genome with polymorphism for at least two of them. In Arabidopsis, maize, and rice, like Pds, Zds was a single-copy gene .In these conditions and in the absence of analysis of controlled progenies, we are unable to conduct genetic analysis of profiles. However it appears that some bands differentiated the basic taxa: one for mandarins, one for pummelos, and one for citrons with EcoRV restriction and one for pummelos and onefor citrons with BamHI restriction. Two bands out of the nine obtained with EcoRV were not observed in the samples of basic taxa. One was rare and only observed in “Rangpur” lime. The other was found in sour oranges, “V olkamer” lemon,and “Palestine sweet” lime suggesting a common ancestor for these three genotypes.This is in agreement with the assumption of Nicolosi et al. that “V olkamer” lemon resμLts from a complex hybrid combination with C. aurantium as one parent. It will be necessary to extend the analysis of the basic taxa to conclude whether these specific bands are present in the diversity of these taxa or resμLt from mutations after the formation of the secondary species.The Lcy-b Gene with RFLP Analysis.After restriction with EcoRV and hybridization with the Lcy-b probe, we obtained simple profiles with a total of four fragments. One to two fragments were observed for each individual, and seven profiles were differentiated among the 25 genotypes. These resμLts provide evidence that Lcy-b is present at a single locus in the haploid Citrus genome. Two lycopene β-cyclases encoded by two genes have been identified in tomato. The B gene encoded a novel type of lycopene β-cyclase whose sequence was similar to capsanthin-capsorubin synthase. The B gene expressed at a high level in βmutants was responsible for strong accumμLation ofβ-carotene in fruit, while in wild-type tomatoes, B was expressed at a low level.The Lcy-b Gene with SSR Analysis. Four bands were detected at locus 1210 (Lcy-b gene). One or two bands were detected per variety confirming that this gene is mono locus. Six different profiles were observed among the 25 genotypes. As with RFLPanalysis, no intrataxon molecμLar polymorphism was found within C. Paradisi, C. Sinensis, and C. Aurantium.Taken together, the information obtained from RFLP and SSR analyses enabled us to identify a complete differentiation among the three basic taxon samples. Each of these taxons displayed two alleles for the analyzed sample. An additional allele was identified for “Mexican” l ime. The profiles for all secondary species can be reconstructed from these alleles. Deduced genetic structure is given in. Sweet oranges and clementine were heterozygous with one mandarin and one pummelo allele. Sour oranges were also heterozygous sharing the same mandarin allele as sweet oranges but with another pummelo allele. Grapefruit were heterozygous with two pummelo alleles. All the acid secondary species were heterozygous, having one allele from citrons and the other one from mandarins except for “Mexican” lime, which had a specific allele.柑桔属类胡萝卜素生物合成途径中七个基因拷贝数目及遗传多样性的分析摘要：本文的首要目标是分析类胡萝卜素生物合成相关等位基因在发生变异柑橘属类胡萝卜素组分种间差异的潜在作用；第二个目标是确定这些基因的拷贝数。