Application of entomological cases in genetics teaching
Kai Wu, Zhaohui Luo,College of Life Sciences, Shangrao Normal University, Shangrao 334001, China通讯作者:
编委: 张飞雄
收稿日期:2018-10-12修回日期:2019-02-2网络出版日期:2019-04-20
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Received:2018-10-12Revised:2019-02-2Online:2019-04-20
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作者简介 About authors
吴凯,博士,讲师,研究方向:昆虫遗传育种E-mail:
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吴凯, 罗朝晖. 昆虫学案例在遗传学教学中的应用[J]. 遗传, 2019, 41(4): 349-358 doi:10.16288/j.yczz.18-286
Kai Wu, Zhaohui Luo.
遗传学是研究遗传和变异规律的科学,是生物学、医学和农学等专业本科生的必修课程。学好遗传学对本科生建立完整的生物学知识框架和理解生命的本质有很大帮助。掌握遗传学知识对遗传病、动植物育种、基因工程、个体发育、免疫、种质资源保护等的研究和生产也有重要意义。案例教学法可以加强学生对理论知识的理解和应用,并提高学生分析、推理、概括和辩论等能力[1],得到广泛应用。已有文献报道案例教学在林学专业和医学专业等遗传学课上获得很大成功[2,3]。
昆虫是地球上最多的动物,已命名的种类有100多万种,占动物界已知种类的2/3[4]。虽然已出版的关于昆虫遗传学书籍为昆虫相关专业的遗传学教学做出了巨大贡献[5,6,7],但内容各有偏重,不适宜现在的本科实际教学。而普通遗传学教材中昆虫学案例较少,对蚕学、蜂学、植物保护等专业的学生而言,难以体现专业相关性,且缺乏近年来的最新研究进展。本文通过对可用于遗传学教学的昆虫案例和研究进展进行梳理,并引入遗传学教学,以期建立具有昆虫相关专业特色的遗传学教学体系,为提升遗传学教学效果提供参考。
1 理论教学体系
关于理论教学,现有遗传学教学体系一般以两条主线讲授:以经典遗传学、细胞遗传学、分子遗传学、核外遗传学、发育遗传学和进化遗传学等的授课主线[8];以遗传信息为中心的主线,即遗传信息的遗传、储存、读取、复制、变异与进化的主线[9]。这两种讲授方法在教学中均有一定的优势。对此,本文按第一条主线将昆虫学案例融入遗传学的授课体系中,形成了具有昆虫相关专业特色的遗传学理论教学框架(54学时) (表1)。Table 1
表1
表1 适用于昆虫学相关专业的本科遗传学理论教学案例
Table 1
教学模块 | 章节(学时) | 采用的昆虫学案例(相关专业内容) |
---|---|---|
绪论 | 1. 课程计划和要求介绍(1) 2. 遗传学发展(2) | 家蚕驯化(遗传、变异和遗传学的概念);昆虫相关遗传发现(遗传学发展史);我国家蚕遗传育种、转基因家蚕和家蚕生物反应器(遗传学的应用)[10] |
经典遗传学 | 1. 分离定律(1) 2. 自由组合定律(2) 3. 孟德尔遗传的拓展(2) 4. 染色体学说(1) 5. 连锁与交换(3) 6. 基因定位(1) 6. 性别决定与伴性遗传(3) 7. 染色体畸变(4) | 果蝇性状的遗传(体色、翅形和眼色等) (基因型和表型;孟德尔定律:分离定律和自由组合定律;伴性遗传);家蚕的皮斑不完全显性遗传;异色瓢虫鞘翅色斑镶嵌显性遗传:包括式和重叠式[8];异色瓢虫的复等位现象(等位基因、非等位基因和复等位基因);果蝇翅的拟表型现象(温度对翅的影响)(基因的作用及与环境的关系);家蚕茧色遗传中的修饰基因[8];昆虫细胞(细胞;细胞分裂和减数分裂;染色体周期性变化;遗传的染色体学说);昆虫染色体(染色体的形态和数目,染色体核型分析);果蝇X染色体连锁遗传(棘眼ec、缺胸刚毛sc和缺横脉cv) (连锁与交换,基因定位)[8];蜜蜂性别决定[11],家蚕性别决定与控制(性别决定)[12];易位在家蚕育种中的应用(染色体结构和数目改变) |
数量遗传学 | 1. 数量性状的遗传学分析(1) 2. 分析数量性状的基本统计方法(1) 3. 遗传变异与遗传率(1) 4. 数量性状基因的定位(1) 5. 近亲繁殖与杂种优势(1) | 家蚕茧质性状(质量性状和数量性状) [13];蜜蜂一些性状的QTL研究(QTL)[14];家蚕杂种优势(近亲繁殖和杂种优势)[12] |
核外遗传学 | 1. 母性影响(1) 2. 细胞质遗传(2) | 麦粉蛾的眼色(母性影响);害虫抗杀虫剂遗传[15],共生微生物沃尔巴克氏体遗传(细胞质遗传)[16] |
分子遗传学 | 1. 遗传物质(1) 2. DNA分子结构与复制(2) 3. 基因的本质(1) 4. 基因突变及分子基础(2) 5. 重组与修复(4) 6. 基因组(2) 7. 基因表达与基因调控(4) 8. 遗传工程与转基因技术(2) | 昆虫基因与基因组(基因,基因组)[17];果蝇突变体(基因突变);平衡致死系(果蝇突变的检出)[8];果蝇突变体的诱发(诱发突变、突变的分子基础和DNA损伤修复);果蝇的P因子(转座子,重组的分子基础);营养因素对蜜蜂幼虫发育影响(表观遗传);AFLP,SNP在昆虫中的应用(基因组多态性);鳞翅目昆虫RNAi(RNAi)[18];CRISPR/Cas9(转基因技术)[19];Flybase数据库(基因组应用) |
发育遗传学 | 1. 个体发育一般模式(1) 2. 基因在胚胎发育中的作用(2) 3. 昆虫变态发育(1) | 果蝇胚胎发育(细胞分化、基因表达调控和胚胎发育)[8];家蚕变态发育(个体发育);柑橘凤蝶皮肤变化(基因表达调控)[20] |
进化遗传学 | 1. 进化理论(1) 2. 分子进化(1) 3. 新种形成(1) 4. 系统发生分析与系统发生树(1) | 突变体果蝇在不同温度下的存活率(适合度、选择系数和基因频率);椒花蛾工业黑化(自然选择);昆虫分子进化与系统分类(进化、进化论、分子进化和系统发生) |
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1.1 绪论
除了对遗传学的基本定义、概念和研究内容讲授以外,遗传学的发展历程也会介绍。同时,为了体现昆虫学相关专业的特点,在普通遗传学的基础之上增加昆虫遗传学的实践意义与应用现状等内容。如在蚕桑生产中,一般雄性家蚕对疾病的抵抗力更高,且吃的食物少,产丝质量高。目前国内用转基因技术对家蚕进行遗传操作,建立了雌性家蚕特异性致死的系统[21],对蚕丝产业的发展具有重大的促进作用;通过转基因技术可以用内源、外源抗病毒基因,病毒RNAi基因,病毒免疫抑制基因等遗传元件改造家蚕,增强抗病毒能力[22];入侵害虫每年都给我国造成严重的经济损失,利用遗传调控技术可对入侵害虫进行防治[23];用家蚕作为生物反应器表达蛛丝蛋白等研究[10]。1.2 经典遗传学
经典遗传学内容主要指1940年以前的工作,是学习遗传学的基础,本科生在中学学过这个模块,很容易导入遗传学课程的学习。除了孟德尔的豌豆实验,果蝇翅的性状杂交实验也可阐述分离定律和自由组合定律[8]。在经典遗传学中,基因间的显隐性关系、环境与表型等,也应补充昆虫学案例,如残翅果蝇(vgvg)的幼虫在高温下饲养,羽化后其翅的大小接近野生型。而对复等位现象、镶嵌遗传的教学可使用异色瓢虫翅色多型案例。由于连锁与交换定律由摩尔根及其同事利用果蝇作为模型研究提出,这在普通遗传学教材中普遍存在,在昆虫相关专业授课中应重点介绍,特别是基因定位中的两点测交或三点测交。在设计染色体及染色体组教学内容时,可以直接以昆虫为例。昆虫染色体有其自身特点,有些昆虫的性染色体组成为XY/XX,鳞翅目昆虫为ZW/ ZZ。但在一部分昆虫(如蝗虫)中,雄性个体只有一条X染色体,没有Y染色体,所以其性染色体组成为XO型。与此类似,鳞翅目昆虫中有一些雌性个体没有W染色体,为ZO型。此外,对于膜翅目的蜜蜂、蚂蚁等昆虫,性别与染色体组的倍数有关,而营养状况决定职能。如蜜蜂(Apis mellifera)的工蜂和蜂王为二倍体(2n=32),但工蜂吃的蜂王浆量少质差,雄蜂为单倍体(n=16)。为了激发学生学习兴趣,可将染色体研究和发现过程插入进来。如昆虫染色体的数目不一,杰克跳蚁(Myrmecia pilosula)只有一对染色体,其孤雌生殖产生的雄蚁只有1条染色体[24],而一种灰蝶科的蝴蝶(Polyommatus (Plebicula) atlanticus)的染色体2n=448-452[25],但这种蝴蝶最初被认为是多倍体生物。
伴性遗传和性别决定有一定联系常在一起讲授。性别决定机制是当今昆虫研究热点领域之一,每年有大量论文发表[26,27]。此部分内容的教学案例以果蝇(Drosophila melanogaster)和家蚕的性别调控机制为主。在普通遗传学教材中,果蝇性别决定一般均有介绍,即果蝇的性别与早期胚胎的性指数(X染色体数目与常染色体组数A的比例)有关,若X∶A=0.5,会关闭性别决定相关基因sxl的表达,发育为雄性;若X∶A=1,sxl基因表达的蛋白Sxl参与另一性别相关基因tra基因转录产物的加工,得到有功能的tra蛋白,tra蛋白与tra2蛋白可以促使雌性特异的dsx蛋白产生,dsx蛋白可抑制雄性性别发育,因此果蝇胚胎发育为雌性。Y染色体与性别没关,只决定雄蝇的可育性,其机制不在此赘述。在家蚕中,W染色体对雌性家蚕性别形成非常重要,但并没有编码蛋白的基因被分离出来,相反,却有大量的转座元件,且雌性家蚕W染色体性别决定区可以产生大量piRNAs[28]。W染色体产生的雌性特异Fem piRNA,是家蚕最初级的性别决定因子[29]。研究表明,在雌性家蚕胚胎中抑制Fem piRNA介导的信号通路会导致产生特异性的doublesex选择性剪接使家蚕向雄性发育[29]。随后的实验证明家蚕组蛋白甲基转移酶BmAsh2在piRNA介导性别决定过程中起到关键作用[30],而雄性家蚕的性别决定和P元件体抑制剂(BmPSI)有关[31]。
在染色体畸变中可增加一些昆虫育种中的应用案例讲解,如利用易位鉴别家蚕的性别。生产上多选用食桑量小、出丝率高的雄蚕来饲养,研究发现卵壳颜色受第10号染色体上的w2 (3.5基因座位上)和w3 (6.9基因座位上)基因控制,纯合体(w2w3/w2w3)的卵壳颜色为浅黄色,各种杂合体为黑色卵壳。家蚕育种工作者利用辐射诱变,先使杂合体(w2+w3/+w2w3)的第10号染色体缺失(缺失的部位:或缺失w2座位,或缺失w3座位),并使有缺失的10号染色体易位到W染色体上,经过系统选育,从后代中选W-10的雌蚕品系(Z/w2+w3,卵黑色)。该品系的雌蚕与浅黄色卵雄蚕(ZZ+w2w3/+w2w3)杂交,后代黑色卵(ZZw2+w3/+w2w3)全为雄性,浅黄色的卵(Z/+w2w3)全为雌性[8]。
1.3 数量遗传学
数量遗传学是遗传学重要内容之一。与孟德尔和摩尔根的质量性状遗传理论不同,数量遗传学是研究数量性状变异规律的学科。很多数量性状都是经济性状:产蜜量,奶牛泌乳量,作物产量等,特点是呈连续变化,没有明显界限,但其表型变异分为遗传变异和环境变异两部分。事实上,数量遗传在昆虫中的应用很早。20世纪90年代,莫建初与唐振华就注意到数量遗传学在害虫种群抗性进化研究中的作用,并提出害虫抗性遗传力被高估或低估的因素[32]。2003年司马杨虎对家蚕茧质性状的数量性状位点(QTL)进行定位分析,发现控制全茧量性状有14个QTL,并分布在14个连锁群上[13]。蜜蜂的取食行为、自卫行为、体长和逆转学习等相关性状均已进行QTL研究[33],对社会性昆虫蜜蜂的数量遗传学研究对生物学发展具有重大意义。自然选择使个体对自然的适应性提高,但数量遗传学的研究对人工选择优良的经济性状及育种有重要意义。这对提高蚕学和蜂学专业的学生学习兴趣很有帮助。1.4 核外遗传学
核外遗传学是研究细胞核以外遗传规律的学科,其教学案例除了叶绿体花斑叶的核外遗传案例,动物中的核外遗传案例似乎很少,但笔者整理发现,昆虫相关的核外遗传案例却不少。例如:一种叶螨(Tetranychus urticae)抗杀虫剂联苯双酯的遗传是完全母性遗传[15],甲壳纲动物的外寄生虫鲑鱼虱(Lepeophtheirus salmonis)对溴氰菊酯的抗性也是通过母性遗传,并降低细胞凋亡[34]。在赤拟谷盗(Tribolium castaneum)中,细菌可以从母体的肠道转移到卵,用来预先增强后代的免疫[35],这在大蜡螟(Galleria mellonella)中也有类似现象[36]。在节肢动物体内普遍存在有一种沃尔巴克氏体(Wolbachia)的共生微生物,它传递给子代的方式便是通过宿主卵细胞质,也是一个可应用于教学的典型案例。沃尔巴克氏体在昆虫体内具有参与调控宿主生殖活动的功能[37]。有研究发现,黄粉蝶(Eurema mandarina)如果感染wFem沃尔巴克氏体,产生的后代全部为雌性,若给wFem感染的雌性蝴蝶饲喂抗生素,会产生雄性后代。这与感染wFem沃尔巴克氏体会引起Z0雌性化、W染色体缺失和破坏Z染色体遗传有关[16]。另外有研究表明内共生体沃尔巴克氏体属可以将自身基因组片段转移到宿主X染色体[38],虽然转入的基因通常没有活性,但可增加宿主的遗传多样性。
1.5 分子遗传学
现代分子生物学技术使遗传学发展突飞猛进,不注重分子遗传学知识的讲授,将不能适应学科发展。但据观察,虽然有些技术已经使用多年,而绝大部分本科生却知之甚少,因此这个模块也是案例梳理和讲授的重点。在教学过程中,一要结合昆虫学案例讲授基本概念、定律、原理、机制,二要对现有的基因技术应用讲授,提高学生学以致用的思维。本模块采用DNA—RNA—蛋白质的路线进行,中间穿插基因组和基因突变、表观遗传和转基因技术等内容。下面仅介绍昆虫基因组和表观遗传两部分案例。对于昆虫的基因组研究,添加国内****做出的贡献,如家蚕(Bombyx mori)、褐飞虱(Nilaparvata lugens)、柑橘凤蝶(Papilio xuthus)、小菜蛾(Plutella xylostella)、烟粉虱(Bemisia tabaci)、飞蝗(Locusta migratoria)和榕小蜂(Agaonidae)等多种昆虫的基因组图谱为我国昆虫学家研究发表[39]。讲授过程中,也可将昆虫基因组大小与植物和动物基因组大小比较,使学生加深对昆虫的认识,培养专业素养。此外,基因组、转录组测序及数据分析已广泛应用到生物学基础研究,增加GenBank和FlyBase等数据库的介绍与使用。
表观遗传学研究的是不涉及DNA序列改变的基因表达和调控的可遗传修饰,包括DNA甲基化、组蛋白修饰、RNA介导的基因沉默等。本处案例以蜜蜂级型分化现象为例,讲解蜜蜂的营养因素怎样通过影响幼虫体内大量基因和蛋白的差异表达导致发育为蜂王和工蜂。研究表明,增加幼虫对蜂王浆的采食量,幼虫的dynactin p62基因甲基化水平会显著降低,而幼虫发育为蜂王的比例会提高[11]。另外,microRNA和组蛋白乙酰化也可调节基因表达,与级型分化有一定关系[40]。
1.6 发育遗传学
哺乳动物受精卵发育成个体以后基本上是由小变大的过程,而昆虫发育为变态发育。完全变态的昆虫会经历卵、幼虫、蛹和成虫等发育阶段,在蛹期会发生剧烈变化,如从毛毛虫到蝴蝶的变化。从遗传学的角度来看,个体发育涉及到核基因组、细胞器基因组和母体基因产物的作用。因此,在设计本模块时,将细胞分化、胚胎发育和个体发育整理规划,具有连贯性。昆虫的发育受到激素调节,保幼激素和蜕皮激素在昆虫发育中起到关键作用。对于昆虫的发育遗传以果蝇胚胎发育的遗传控制研究的最为成熟,在多数教材中均有涉及。在对果蝇胚胎发育中的母体效应基因,裂隙基因,成对规则基因以及体节极性基因的基础上,增加讲授一些新的研究,如对果蝇30个不同发育时期进行RNA-Seq、tiling microarrays和cDNA序列分析,发现基因转录在整个发育过程中是动态变化的[41];其它鳞翅目昆虫的变态发育,特别是家蚕的研究,也是很好的案例。例如FOXO转录因子对家蚕生长发育的调控主要通过调节保幼激素的降解实现[42]。柑橘凤蝶幼虫皮肤发育也值得关注,其1~4龄幼虫皮肤为鸟粪状,5龄幼虫皮肤为绿色。为何4龄以前的蜕皮皮肤模式相差不大,而4~5龄的蜕皮皮肤差异巨大?通过microarray数据分析发现,在不同时期的幼虫有大量基因的转录水平发生变化,并且E75基因可能和幼虫皮肤变化有很大关系[20]。
将现有文献整理成教学案例,可以开扩学生视野,使其了解最新研究进展,同时也促进教师教学相长。
1.7 进化遗传学
进化遗传学部分有一个经典的昆虫案例,即自然选择的例子“工业黑化”。欧洲的产业革命使一些地区逐渐工业化,这使许多鳞翅目昆虫的黑色型个体频率逐渐上升。在曼彻斯特,最初黑色型椒花蛾频率很低,但从工业化以后,黑色型稳定上升,达95%以上。但从近年来的昆虫进化与遗传学研究发展来看,昆虫相关专业的遗传学教学内容应该补充一些新知识。昆虫系统发育学是研究昆虫类群亲缘关系、进化地位、分子演化和起源的学科,是昆虫学研究的一个重要领域。将昆虫系统发育的案例应用到遗传学教学中来,会使本科生对昆虫系统发育研究方向有进一步了解,对以后读研深造或从事相关科研工作均有帮助。例如:飞蝗虽然只有一个种,但有10个亚种。这些亚种因不同地域特点存在不同形态特征。传统的形态学测量方法区分飞蝗亚种具有很多缺点,如卵的滞育率,抗寒性是连续的,而且外部形态特征易受环境影响发生变化,而分子标记法如RAPD、微卫星和mtDNA等方法为分类和进化提供了有效手段,进而提示飞蝗不同地理种群的遗传多样性[43]。通过遗传多样性比较分析和近缘属的分布研究表明飞蝗起源于非洲,与人类走出非洲理论吻合[43]。此外,烟盲蝽及其近缘种的种群遗传学研究均可用于遗传学教学。利用线粒体基因进行系统发育学的研究,可以用来鉴定昆虫的系统进化关系。在害虫防治方面,天敌昆虫种群遗传学的应用可以为引进天敌昆虫进行生物防治提供理论基础[44]。
2 遗传学实验教学设计
实验教学有助于学生掌握基础知识,发现问题,总结归纳,带动后续课程的学习。因此,实验教学体系的设计既要有基本的验证性实验,也要兼顾综合性和探究性实验对学生科研素质的培养。为此,在昆虫相关专业遗传学实验中可以添加经典的昆虫染色体的观察实验[45,46],双翅目昆虫幼虫的唾腺细胞、肠细胞、气管细胞中存在多线染色体,这也是昆虫中很好的案例,供学生了解染色体和实验观察。除此之外,最好将现代生物学实验方法融入到遗传学实验中。根据昆虫相关专业的特点和学生培养目标的要求,可以设置以下实验(表2)。
Table 2
表2
表2 适用于昆虫相关本科专业遗传学实验设计
Table 2
序号 | 实验性质 | 实验名称 | 实验内容 |
---|---|---|---|
1 | 验证性 | 昆虫幼虫、成虫性别鉴定 | 家蚕、果蝇等昆虫幼虫、成虫性别鉴定,成虫交配 |
2 | 验证性 | 果蝇唾腺染色体观察 | 果蝇三龄末期幼虫唾腺解剖,染色,染色体观察 |
3 | 验证性 | 环境与表型—温度对果蝇卷翅程度的影响 | 3种温度下培养cu果蝇,观察翅的卷曲程度 |
4 | 综合性 | 果蝇杂交实验(单因子,双因子,伴性遗传) | 灰体残翅(EEvgvg)与黑檀体长翅(eeVgVg)果蝇的正反交;红眼与白眼果蝇正反交 |
5 | 综合性 | 果蝇Gal4-UAS系统检测基因在特定部位表达 | 果蝇品系Da-Gal4与UAS-GFP杂交,诱导全身表达GFP,果蝇品系NP3084-Gal4与UAS-GFP杂交,诱导中肠、唾液腺等表达GFP,子代果蝇解剖,荧光显微镜观察GFP信号 |
6 | 探究性 | 野外昆虫采集及基于COI gene测序鉴定 | 昆虫采集,基因组提取,PCR,DNA电泳,回收,测序,结果分析(Database)[47] |
7 | 探究性 | 昆虫基因PCR扩增 | 目的片段的扩增和酶切,凝胶检测,基因型判定[48] |
新窗口打开|下载CSV
验证性实验3个:(1)昆虫幼虫、成虫性别鉴定:包括果蝇饲料配置,果蝇生活史观察,果蝇雌雄鉴别;(2)果蝇唾腺染色体的观察;(3)环境与表型的关系—温度对果蝇卷翅程度的影响。
综合性实验2个:(1)果蝇杂交实验(单因子,双因子,伴性遗传)。单因子杂交,双因子杂交,伴性遗传的实验含有统计学分析,要求学生使用卡方检验判断F2的比例等。(2)果蝇Gal4—UAS系统检测基因在特定部位表达。Gal4—UAS系统是果蝇中常用的研究基因表达和功能的方法[49,50]。以果蝇作为模式生物进行科学研究必需具备果蝇遗传杂交实验技能,特别是平衡子和Gal4—UAS系统的应用,其重要性不言而喻。因此,在实验中安排“果蝇Gal4— UAS系统检测基因在特定部位表达”的实验。由于GFP蛋白的绿色荧光信号便于观察,所以使用UAS- GFP果蝇品系。
探究性实验2个:(1)野外昆虫采集及基于细胞色素氧化酶亚基I (COI)基因测序鉴定;(2)昆虫基因PCR扩增。在遗传学实验中常规分子生物学实验技术训练较少的问题得到普遍关注[51]。目前已有高校将经典实验与新技术融合的理念引入遗传学实验教学改革中[52,53]。但实验教学改革也应和学校硬件、软件条件相适应,例如复旦大学、上海交通大学在本科生的实验中引入CRISPR/Cas9系统定点敲除的实验[53],在一般大学很难完成。因此较为前沿的技术CRISPR/Cas9技术原理可在理论课上详细讲解。DNA条码(DNA barcoding)是一种很好的物种鉴定分子工具,因结果非常可靠,已广泛应用于昆虫分类研究中。目前国外已有教师将襀翅目(Plecoptera)的石蝇(stoneflies) COI DNA条码分析应用于遗传学实验教学中,取得了很好的教学效果[47]。对此,在昆虫相关专业的遗传学实验中,增加这一探究性实验,由学生自己去采集昆虫,通过形态描述分类,结合遗传学COI基因的扩增、测序和分析的实验,提高专业能力和科研素质。
综合本实验设计,既含有验证性的昆虫性别、染色体观察等验证性实验,也含有果蝇饲养,生活史观察,环境与表型关系,杂交等综合性实验,也兼顾了分子遗传学方法和技能的培养,能够有效满足培养高素质昆虫相关专业学生的需求。
3 结语
遗传工具创新和应用使遗传学急速发展,新的知识产生使分子遗传学内容越来越多,复杂的分子机制和遗传学新内容的整合对本科生学好遗传学是一个巨大的挑战。对于昆虫相关专业的本科生来说,如何学习和掌握昆虫遗传学知识,了解当前昆虫研究动态、方向,对高校培养高素质、专业能力强的昆虫优秀人才有着极其重要的意义。本文对昆虫学领域中的遗传学案例进行了梳理,建立了具有昆虫相关专业特色的昆虫遗传学理论教学体系和实验教学设计,能够跟上学科发展的步伐,也使学生对所学专业有更深入的认识。在遗传学教学过程中,并不提倡全部使用昆虫学案例而舍弃应用普通遗传学教材中的经典案例。而且,有些知识点在昆虫中缺少合适的案例,如在动物界自然产生的多倍体是非常罕见的,虽然曾在鱼类、鸟类、两栖类等动物中有多倍性个体报道,但都不能形成类群[54]。在昆虫中,单倍体、二倍体比较常见,多倍体昆虫也有报道,但自然界中异源多倍体的昆虫学案例鲜有报道。因此使用异源八倍体小黑麦的例子进行讲授就非常重要。所以,昆虫学案例在遗传学教学中的应用只是替代了一些普通遗传学教材中的案例,增加了一些其中没有的案例,来促进教学。
参考文献 原文顺序
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遗传学是林学专业本科生普遍反映最难学习的必修课程之一,传统的讲授式教学很难满足遗传学教学的需求。根据林学专业的理论特点和实际需求,结合近几年的教学和科研经验,选取了'开棺验亲'、'黑果枸杞茎刺'、'哈利·波特与魔法力'等一系列典型的案例应用于林学专业的遗传学教学。实践证明针对遗传学的案例教学能培养学生的学习能力和创造力、激发学生学习兴趣和学习的主动性,同时也培养了学生良好的个性品质并在一定程度上增强知识学习的系统性。
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遗传学是林学专业本科生普遍反映最难学习的必修课程之一,传统的讲授式教学很难满足遗传学教学的需求。根据林学专业的理论特点和实际需求,结合近几年的教学和科研经验,选取了'开棺验亲'、'黑果枸杞茎刺'、'哈利·波特与魔法力'等一系列典型的案例应用于林学专业的遗传学教学。实践证明针对遗传学的案例教学能培养学生的学习能力和创造力、激发学生学习兴趣和学习的主动性,同时也培养了学生良好的个性品质并在一定程度上增强知识学习的系统性。
URL [本文引用: 1]
遗传学是生命科学、医学、农学等相关领域的核心课程.作为21世纪生命科学中发展最为迅速的学科之一,教学内容复杂、更新快,遗传学知识对人一生的影响也日益增强,特别是与医学相关的遗传学知识更是受到大众关注.为使学生更容易理解深奥的遗传学知识,使教学内容更贴近生活,在教学过程中引入医学病例,将相应的医学病例同遗传学理论知识结合并作出适当的延伸,将有利于提高学生的遗传学知识综合分析能力,同时提高学生的学习积极性和实用技能.本文根据现代遗传学教学体系,引入相应的医学病例,强调培养学生综合遗传分析能力,为综合性大学、师范院校的普通遗传学教学提供参考.
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URL [本文引用: 1]
遗传学是生命科学、医学、农学等相关领域的核心课程.作为21世纪生命科学中发展最为迅速的学科之一,教学内容复杂、更新快,遗传学知识对人一生的影响也日益增强,特别是与医学相关的遗传学知识更是受到大众关注.为使学生更容易理解深奥的遗传学知识,使教学内容更贴近生活,在教学过程中引入医学病例,将相应的医学病例同遗传学理论知识结合并作出适当的延伸,将有利于提高学生的遗传学知识综合分析能力,同时提高学生的学习积极性和实用技能.本文根据现代遗传学教学体系,引入相应的医学病例,强调培养学生综合遗传分析能力,为综合性大学、师范院校的普通遗传学教学提供参考.
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URLMagsci [本文引用: 1]
文章分析了遗传学教学面临的问题, 对遗传学教学架构以及与其他课程的内容衔接进行了探讨, 认为以遗传信息为中心重新组织教学内容, 保证遗传学教学内容的完整性和系统性, 凸显遗传学特色。根据遗传学25章教学内容的相关性重新组合成4个模块, 即遗传信息的遗传、遗传信息的储存、遗传信息的读取、遗传信息的复制、变异与进化。各模块紧扣遗传信息这一主题—— 也是遗传现象的内在联系, 每个模块讲解遗传信息的一个方面。对比与其他课程重叠的内容, 提取其中涉及遗传信息的部分, 重点讲解遗传信息的流动和变化。以遗传信息为主线的遗传学教学使课堂既充满遗传学特色, 又易于被学生接受和掌握。
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URLMagsci [本文引用: 1]
文章分析了遗传学教学面临的问题, 对遗传学教学架构以及与其他课程的内容衔接进行了探讨, 认为以遗传信息为中心重新组织教学内容, 保证遗传学教学内容的完整性和系统性, 凸显遗传学特色。根据遗传学25章教学内容的相关性重新组合成4个模块, 即遗传信息的遗传、遗传信息的储存、遗传信息的读取、遗传信息的复制、变异与进化。各模块紧扣遗传信息这一主题—— 也是遗传现象的内在联系, 每个模块讲解遗传信息的一个方面。对比与其他课程重叠的内容, 提取其中涉及遗传信息的部分, 重点讲解遗传信息的流动和变化。以遗传信息为主线的遗传学教学使课堂既充满遗传学特色, 又易于被学生接受和掌握。
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Spider silk is one of the best natural fibers and has superior mechanical properties. However, the large-scale harvesting of spider silk by rearing spiders is not feasible, due to their territorial and cannibalistic behaviors. The silkworm, Bombyx mori, has been the most well known silk producer for thousands of years and has been considered an ideal bioreactor for producing exogenous proteins, including spider silk. Previous attempts using transposon-mediated transgenic silkworms to produce spider silk could not achieve efficient yields, due to variable promoter activities and endogenous silk fibroin protein expression. Here, we report a massive spider silk production system in B. mori by using transcription activator-like effector nuclease-mediated homology-directed repair to replace the silkworm fibroin heavy chain gene (FibH) with the major ampullate spidroin-1 gene (MaSp1) in the spider Nephila clavipes. We successfully replaced the 16-kb endogenous FibH gene with a 1.6-kb MaSp1 gene fused with a 1.1-kb partial FibH sequence and achieved up to 35.2% chimeric MaSp1 protein amounts in transformed cocoon shells. The presence of the MaSp1 peptide significantly changed the mechanical characteristics of the silk fiber, especially the extensibility. Our study provides a native promoter-driven, highly efficient system for expressing the heterologous spider silk gene instead of the transposon-based, random insertion of the spider gene into the silkworm genome. Targeted MaSp1 integration into silkworm silk glands provides a paradigm for the large-scale production of spider silk protein with genetically modified silkworms, and this approach will shed light on developing new biomaterials.
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URL [本文引用: 2]
家蚕是重要的经济昆虫,大多数重要经济性状都呈数量性状遗传,家蚕茧质性状就属于其中之一.需要用数理统计学的方法把控制某一数量性状的多个基因作为一个整体进行研究.因此把数量遗传学和分子遗传学相互结合,将形态性状构建的遗传图谱发展为高密度的分子连锁图,从分子水平上操纵家蚕一些重要经济性状基因,对实现分子育种具有十分重要的意义.该论文的主要研究结果如下:1.家蚕AFLP分子连锁图谱的构建;该研究采用了两个遗传差异比较大的现行生产用家蚕品种872和湘晖作为作图亲本材料,杂交得F1代,自交后得F2代,从F2代随机抽取91个个体作为作图群体...
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URL [本文引用: 2]
家蚕是重要的经济昆虫,大多数重要经济性状都呈数量性状遗传,家蚕茧质性状就属于其中之一.需要用数理统计学的方法把控制某一数量性状的多个基因作为一个整体进行研究.因此把数量遗传学和分子遗传学相互结合,将形态性状构建的遗传图谱发展为高密度的分子连锁图,从分子水平上操纵家蚕一些重要经济性状基因,对实现分子育种具有十分重要的意义.该论文的主要研究结果如下:1.家蚕AFLP分子连锁图谱的构建;该研究采用了两个遗传差异比较大的现行生产用家蚕品种872和湘晖作为作图亲本材料,杂交得F1代,自交后得F2代,从F2代随机抽取91个个体作为作图群体...
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蜜蜂(Apism ellifera)及其同属的昆虫正日益成为遗传学研究的重要试验材料,本文以性别决定为主要线索,展示了蜜蜂遗传学150多年的丰富历史和蜜蜂遗传学的发展前景。1、蜜蜂遗传学的起源蜜蜂遗传学起始于Johann Dzierzon。1845年,Johann Dzierzon发表了他的假说,认为雄蜂来源
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URL [本文引用: 1]
蜜蜂(Apism ellifera)及其同属的昆虫正日益成为遗传学研究的重要试验材料,本文以性别决定为主要线索,展示了蜜蜂遗传学150多年的丰富历史和蜜蜂遗传学的发展前景。1、蜜蜂遗传学的起源蜜蜂遗传学起始于Johann Dzierzon。1845年,Johann Dzierzon发表了他的假说,认为雄蜂来源
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URLPMID:17046600 [本文引用: 2]
Bifenazate is a selective hydrazine carbazate acaricide launched in 1999 and reported to be neurotoxic, since preliminary studies on the mode of action suggested that bifenazate may act on GABA-gated chloride channels. However, this information has not yet been supported by mechanistic studies. Therefore bifenazate is still considered as a neuronal inhibitor, but with unknown mode of action. Here we report an alternative hypothesis on the mode of action of bifenazate, i.e. its possible interference with a non-neuronal target site. An acaricide susceptible strain of Tetranychus urticae Koch (Acari: Tetranychidae), LS-VL, was artificially selected for bifenazate resistance, and after 36 generations an extremely high resistance ratio (RR) of >164,000 was obtained. This bifenazate-resistant strain (BR-VL) lacks cross-resistance to many different chemical classes and modes of action of other acaricides. In order to check for metabolic resistance mechanisms, synergists known to inhibit well-known detoxification routes were used together with in vitro enzymatic assays. No synergism or highly increased detoxification activity was observed in the resistant strain. However, the organophosphorous esterase inhibitor S,S,S-tributylphosphorotrithioate (DEF) applied to the susceptible strain could completely antagonise the acaricidal efficacy of bifenazate, suggesting that bifenazate is a pro-acaricide, not active by itself, that needs in vivo activation by esterases. Reciprocal crosses of diploid females and haploid males of strains LS-VL (susceptible) and BR-VL (bifenazate resistant) revealed that bifenazate resistance was inherited completely maternally, i.e. resistance is fully dominant when susceptible males were crossed with resistant females, and fully recessive when resistant males were crossed with susceptible females. Such an inheritance pattern has to our knowledge never been observed before in the case of insecticide/acaricide resistance. This observation may suggest a target-site for bifenazate encoded by the mitochondrial genome. Further evidence supporting such a hypothesis was obtained when measuring the ATP-level in spider mites treated with bifenazate. The ATP content in bifenazate treated mites declined progressively between 0 and 4 h after treatment, similarly to mites treated with the complex I inhibitor fenpyroximate, an acaricide known to interfere with mitochondrial function. The obtained results suggest a target-site other than GABA-gated chloride channels, most likely encoded by and located in the mitochondria.
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URL [本文引用: 2]
Abstract Wolbachia is a maternally inherited ubiquitous endosymbiotic bacterium of arthropods that displays a diverse repertoire of host reproductive manipulations. For the first time, we demonstrate that Wolbachia manipulates sex chromosome inheritance in a sexually reproducing insect. Eurema mandarina butterfly females on Tanegashima Island, Japan, are infected with the w Fem Wolbachia strain and produce all-female offspring, while antibiotic treatment results in male offspring. Fluorescence in situ hybridization (FISH) revealed that w Fem-positive and w Fem-negative females have Z0 and WZ sex chromosome sets, respectively, demonstrating the predicted absence of the W chromosome in w Fem-infected lineages. Genomic quantitative polymerase chain reaction (qPCR) analysis showed that w Fem-positive females lay only Z0 eggs that carry a paternal Z, whereas females from lineages that are naturally w Fem-negative lay both WZ and ZZ eggs. In contrast, antibiotic treatment of adult w Fem females resulted in the production of Z0 and ZZ eggs, suggesting that this Wolbachia strain can disrupt the maternal inheritance of Z chromosomes. Moreover, most male offspring produced by antibiotic-treated w Fem females had a ZZ karyotype, implying reduced survival of Z0 individuals in the absence of feminizing effects of Wolbachia . Antibiotic treatment of w Fem-infected larvae induced male-specific splicing of the doublesex ( dsx ) gene transcript, causing an intersex phenotype. Thus, the absence of the female-determining W chromosome in Z0 individuals is functionally compensated by Wolbachia -mediated conversion of sex determination. We discuss how Wolbachia may manipulate the host chromosome inheritance and that Wolbachia may have acquired this coordinated dual mode of reproductive manipulation first by the evolution of female-determining function and then cytoplasmically induced disruption of sex chromosome inheritance.
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URLPMID:15591204 [本文引用: 1]
We report a draft sequence for the genome of the domesticated silkworm (Bombyx mori), covering 90.9% of all known silkworm genes. Our estimated gene count is 18,510, which exceeds the 13,379 genes reported for Drosophila melanogaster. Comparative analyses to fruitfly, mosquito, spider, and butterfly reveal both similarities and differences in gene content.
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URLPMID:25561900 [本文引用: 1]
RNA interference has been described as a powerful genetic tool for gene functional analysis and a promising approach for pest management. However, RNAi efficiency varies significantly among insect species due to distinct RNAi machineries. Lepidopteran insects include a large number of pests as well as model insects, such as the silkworm,Bombyx mori. However, only limited success ofin vivoRNAi has been reported in lepidoptera, particularly during the larval stages when the worms feed the most and do the most harm to the host plant. Enhancing the efficiency of larval RNAi in lepidoptera is urgently needed to develop RNAi-based pest management strategies. In the present study, we investigate the function of the conserved RNAi core factor, Argonaute2 (Ago2), in mediatingB. moriRNAi efficiency. We demonstrate that introducingBmAgo2dsRNA inhibits the RNAi response in both BmN cells and embryos. Furthermore, we establish several transgenic silkworm lines to assess the roles ofBmAgo2in larval RNAi. Over-expressingBmAgo2significantly facilitated both dsRNA-mediated larval RNAi when targetingDsRedusing dsRNA injection and shRNA-mediated larval RNAi when targetingBmBlos2using transgenic shRNA expression. Our results show that BmAgo2 is involved in RNAi inB. moriand provides a promising approach for improving larval RNAi efficiency inB. moriand in lepidopteran insects in general.
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URLPMID:4094479 [本文引用: 1]
We report the establishment of an efficient and heritable gene mutagenesis method in the silkworm Bombyx mori using modified type II clustered regularly interspaced short palindromic repeats (CRISPR) with an associated protein (Cas9) system. Using four loci Bm-ok, BmKMO, BmTH, and Bmtan as candidates, we proved that genome alterations at specific sites could be induced by direct microinjection of specific guide RNA and Cas9-mRNA into silkworm embryos. Mutation frequencies of 16.7-35.0% were observed in the injected generation, and DNA fragments deletions were also noted. Bm-ok mosaic mutants were used to test for mutant heritability due to the easily determined translucent epidermal phenotype of Bm-ok-disrupted cells. Two crossing strategies were used. In the first, injected Bm-ok moths were crossed with wild-type moths, and a 28.6% frequency of germline mutation transmission was observed. In the second strategy, two Bm-ok mosaic mutant moths were crossed with each other, and 93.6% of the offsprings appeared mutations in both alleles of Bm-ok gene (compound heterozygous). In summary, the CRISPR/Cas9 system can act as a highly specific and heritable gene-editing tool in Bombyx mori.
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URLPMID:3386895 [本文引用: 2]
Background Body coloration is an ecologically important trait that is often involved in prey-predator interactions through mimicry and crypsis. Although this subject has attracted the interest of biologists and the general public, our scientific knowledge on the subject remains fragmentary. In the caterpillar of the swallowtail butterfly Papilio xuthus, spectacular changes in the color pattern are observed; the insect mimics bird droppings (mimetic pattern) as a young larva, and switches to a green camouflage coloration (cryptic pattern) in the final instar. Despite the wide variety and significance of larval color patterns, few studies have been conducted at a molecular level compared with the number of studies on adult butterfly wing patterns. Results To obtain a catalog of genes involved in larval mimetic and cryptic pattern formation, we constructed expressed sequence tag (EST) libraries of larval epidermis for P. xuthus, and P. polytes that contained 20,736 and 5,376 clones, respectively, representing one of the largest collections available in butterflies. A comparison with silkworm epidermal EST information revealed the high expression of putative blue and yellow pigment-binding proteins in Papilio species. We also designed a microarray from the EST dataset information, analyzed more than five stages each for six markings, and confirmed spatial expression patterns by whole-mount in situ hybridization. Hence, we succeeded in elucidating many novel marking-specific genes for mimetic and cryptic pattern formation, including pigment-binding protein genes, the melanin-associated gene yellow-h3, the ecdysteroid synthesis enzyme gene 3-dehydroecdysone 3b-reductase, and Papilio-specific genes. We also found many cuticular protein genes with marking specificity that may be associated with the unique surface nanostructure of the markings. Furthermore, we identified two transcription factors, spalt and ecdysteroid signal-related E75, as genes expressed in larval eyespot markings. This finding suggests that E75 is a strong candidate mediator of the hormone-dependent coordination of larval pattern formation. Conclusions This study is one of the most comprehensive molecular analyses of complicated morphological features, and it will serve as a new resource for studying insect mimetic and cryptic pattern formation in general. The wide variety of marking-associated genes (both regulatory and structural genes) identified by our screening indicates that a similar strategy will be effective for understanding other complex traits.
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"生物入侵"是指某种生物从外地自然传入或人为引种后成为野生状态,并对本地生态系统造成一定危害的现象。在缺乏天敌和其他制约因子存在的前提下,入侵种能够快速繁殖和扩增并对当地的生态环境、生物多样性和经济造成严重的损失。随着全球化进程的发展,生物入侵变得更加普遍并且危害更加严重,加强入侵种的治理至关重要。由于传统的物理和化学方法在入侵种防治中存在着一些难以解决的问题,开发和利用无污染、无公害的遗传调控技术在生物入侵种的综合治理方面就显得非常迫切。文章针对我国入侵害虫的现状、主要入侵方式及目前的防治措施进行了总结,同时对遗传调控技术及其在生物入侵种综合治理方面的应用进行了阐述,以期为我国生物入侵的科学治理提供参考。
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URL [本文引用: 1]
"生物入侵"是指某种生物从外地自然传入或人为引种后成为野生状态,并对本地生态系统造成一定危害的现象。在缺乏天敌和其他制约因子存在的前提下,入侵种能够快速繁殖和扩增并对当地的生态环境、生物多样性和经济造成严重的损失。随着全球化进程的发展,生物入侵变得更加普遍并且危害更加严重,加强入侵种的治理至关重要。由于传统的物理和化学方法在入侵种防治中存在着一些难以解决的问题,开发和利用无污染、无公害的遗传调控技术在生物入侵种的综合治理方面就显得非常迫切。文章针对我国入侵害虫的现状、主要入侵方式及目前的防治措施进行了总结,同时对遗传调控技术及其在生物入侵种综合治理方面的应用进行了阐述,以期为我国生物入侵的科学治理提供参考。
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URLPMID:17839565 [本文引用: 1]
A new sibling species of the primitive Australian ant Myrmecia pilosula has a chromosome number of n = 1. C-banding techniques confirm that the two chromosomes of workers are homologous. Males are haploid, as in other Hymenoptera, and their somatic cells contain only a single chromosome. This new species is potentially of great importance in both laboratory and field studies on gene organization.
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URLPMID:22020973 [本文引用: 1]
http://rnajournal.cshlp.org/cgi/doi/10.1261/rna.027565.111
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URLPMID:29474354 [本文引用: 1]
Author(s): Li, Z; You, L; Yan, D; James, AA; Huang, Y; Tan, A | Abstract: Sex determination is a hierarchically-regulated process with high diversity in different organisms including insects. The W chromosome-derived Fem piRNA has been identified as the primary sex determination factor in the lepidopteran insect, Bombyx mori, revealing a distinctive piRNA-mediated sex determination pathway. However, the comprehensive mechanism of silkworm sex determination is still poorly understood. We show here that the silkworm PIWI protein BmSiwi, but not BmAgo3, is essential for silkworm sex determination. CRISPR/Cas9-mediated depletion of BmSiwi results in developmental arrest in oogenesis and partial female sexual reversal, while BmAgo3 depletion only affects oogenesis. We identify three histone methyltransferases (HMTs) that are significantly down-regulated in BmSiwi mutant moths. Disruption one of these, BmAsh2, causes dysregulation of piRNAs and transposable elements (TEs), supporting a role for it in the piRNA signaling pathway. More importantly, we find that BmAsh2 mutagenesis results in oogenesis arrest and partial female-to-male sexual reversal as well as dysregulation of the sex determination genes, Bmdsx and BmMasc. Mutagenesis of other two HMTs, BmSETD2 and BmEggless, does not affect piRNA-mediated sex determination. Histological analysis and immunoprecipitation results support a functional interaction between the BmAsh2 and BmSiwi proteins. Our data provide the first evidence that the HMT, BmAsh2, plays key roles in silkworm piRNA-mediated sex determination.
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URLPMID:5289617 [本文引用: 1]
Abstract Manipulation of sex determination pathways in insects provides the basis for a wide spectrum of strategies to benefit agriculture and public health. Furthermore, insects display a remarkable diversity in the genetic pathways that lead to sex differentiation. The silkworm, Bombyx mori, has been cultivated by humans as a beneficial insect for over two millennia, and more recently as a model system for studying lepidopteran genetics and development. Previous studies have identified the B. mori Fem piRNA as the primary female determining factor and BmMasc as its downstream target, while the genetic scenario for male sex determination was still unclear. In the current study, we exploite the transgenic CRISPR/Cas9 system to generate a comprehensive set of knockout mutations in genes BmSxl, Bmtra2, BmImp, BmImpM, BmPSI and BmMasc, to investigate their roles in silkworm sex determination. Absence of Bmtra2 results in the complete depletion of Bmdsx transcripts, which is the conserved downstream factor in the sex determination pathway, and induces embryonic lethality. Loss of BmImp or BmImpM function does not affect the sexual differentiation. Mutations in BmPSI and BmMasc genes affect the splicing of Bmdsx and the female reproductive apparatus appeared in the male external genital. Intriguingly, we identify that BmPSI regulates expression of BmMasc, BmImpM and Bmdsx, supporting the conclusion that it acts as a key auxiliary factor in silkworm male sex determination.
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自1908年Melander[1]首次发现美国的梨园蚧AspidiotusperniciosusComstock对石硫合剂有抗药性以来,已有500多种害虫和害螨对一种或多种不同类群的杀虫剂产生了抗药性[2]。Dobzhansky[3]认为,杀虫剂抗性是一种进化现象,是害虫种群内部遗传结构在杀虫剂选择作用下持续变化的
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URL [本文引用: 1]
自1908年Melander[1]首次发现美国的梨园蚧AspidiotusperniciosusComstock对石硫合剂有抗药性以来,已有500多种害虫和害螨对一种或多种不同类群的杀虫剂产生了抗药性[2]。Dobzhansky[3]认为,杀虫剂抗性是一种进化现象,是害虫种群内部遗传结构在杀虫剂选择作用下持续变化的
URLMagsci [本文引用: 1]
<SPAN >继果蝇、按蚊和家蚕之后,意大利蜜蜂</SPAN><I ><SPAN lang=EN-US >Apis mellifera</SPAN></I><SPAN >(膜翅目:</SPAN><SPAN > </SPAN><SPAN >蜜蜂科)成为又一种被完整测得基因组序列的昆虫。从此,蜜蜂研究进入后基因组时代。作为一种典型的社会性昆虫,许多和蜜蜂社会生活紧密相关的性状都是数量性状。这些性状研究中广泛涉及到了数量性状位点(</SPAN><SPAN lang=EN-US >quantitative traits loci</SPAN><SPAN >,</SPAN><SPAN lang=EN-US >QTL</SPAN><SPAN >)定位研究。本文综述了应用</SPAN><SPAN lang=EN-US >QTL</SPAN><SPAN >对蜜蜂取食行为、自卫行为、体长、逆转学习等的研究现状,同时结合国内外最新研究进展,总结并展望了后基因组时代蜜蜂</SPAN><SPAN lang=EN-US >QTL</SPAN><SPAN >的研究方向。</SPAN>
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URLMagsci [本文引用: 1]
<SPAN >继果蝇、按蚊和家蚕之后,意大利蜜蜂</SPAN><I ><SPAN lang=EN-US >Apis mellifera</SPAN></I><SPAN >(膜翅目:</SPAN><SPAN > </SPAN><SPAN >蜜蜂科)成为又一种被完整测得基因组序列的昆虫。从此,蜜蜂研究进入后基因组时代。作为一种典型的社会性昆虫,许多和蜜蜂社会生活紧密相关的性状都是数量性状。这些性状研究中广泛涉及到了数量性状位点(</SPAN><SPAN lang=EN-US >quantitative traits loci</SPAN><SPAN >,</SPAN><SPAN lang=EN-US >QTL</SPAN><SPAN >)定位研究。本文综述了应用</SPAN><SPAN lang=EN-US >QTL</SPAN><SPAN >对蜜蜂取食行为、自卫行为、体长、逆转学习等的研究现状,同时结合国内外最新研究进展,总结并展望了后基因组时代蜜蜂</SPAN><SPAN lang=EN-US >QTL</SPAN><SPAN >的研究方向。</SPAN>
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Abstract Resistance towards deltamethrin (DMT) in the crustacean ectoparasite Lepeophtheirus salmonis (Caligidae) is a problem on fish farms lining the North Atlantic Ocean. Two Norwegian strains with different susceptibility towards DMT were crossed in the parental generation (P0), females from a sensitive strain were crossed with males from a resistant strain and vice versa. Individual susceptibility towards DMT was assessed in the second filial generation (F2). DMT resistance was only found in F2 descendants when the P0 females were from the resistant strain, pointing to maternal inheritance. Since maternal inheritance might be linked to the mitochondrial (mt) genome, the nucleotide sequences and the gene expressions of mt-genes were analysed. Twenty non-synonymous single nucleotide polymorphisms (SNPs) were identified in mt-transcripts from resistant F2 parasites, including SNPs in two cytochrome C oxidase subunits (COX1 and COX3) and two subunits of the NADH dehydrogenase complex (ND1 and ND5) previously linked to DMT resistance in the salmon louse. Differential expression analysis between the sensitive and resistant strain revealed strain effect in seven out of twelve mt-genes. The current study also show that DNA fragmentation (indicating apoptosis) was affected by DMT exposure in skeletal muscle tissue and that resistant parasites undergo less apoptosis than sensitive parasites.
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URLPMID:26701756 [本文引用: 1]
Invertebrates can be primed to enhance their protection against pathogens they have encountered before. This enhanced immunity can be passed maternally or paternally to the offspring and is known as transgenerational immune priming. We challenged larvae of the red flour beetleTribolium castaneumby feeding them on diets supplemented withEscherichia coli,Micrococcus luteusorPseudomonas entomophila, thus mimicking natural exposure to pathogens. The oral uptake of bacteria induced immunity-related genes in the offspring, but did not affect the methylation status of the egg DNA. However, we observed the translocation of bacteria or bacterial fragments from the gut to the developing eggs via the female reproductive system. Such translocating microbial elicitors are postulated to trigger bacterial strain-specific immune responses in the offspring and provide an alternative mechanistic explanation for maternal transgenerational immune priming in coleopteran insects.
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URLPMID:4063815 [本文引用: 1]
Parents invest in their offspring by preparing them for defense against pathogens and parasites that only the parents have encountered, a phenomenon known as trans-generational immune priming. We investigated the underlying mechanism using the established lepidopteran model host Galleria mellonella. When larvae were fed with non-pathogenic bacteria, or the entomopathogenic species Pseudomonas entomophila and Serratia entomophila, the activity of lysozyme and phenoloxidase increased in the hemolymph, and immunity-related genes encoding antibacterial proteins such as gloverin were induced. Remarkably, the ingestion of bacteria by female larvae resulted in the differential expression of immunity-related genes in the eggs subsequently laid by the same females, providing evidence for trans-generational immune priming in G. mellonella. To determine the fate of these ingested microbes, the larval diet was supplemented with bacteria carrying a fluorescent label. We observed these bacteria crossing the midgut epithelium, their entrapment within nodules in the hemocoel, their accumulation within the ovary, and ultimately their deposition in the eggs. Therefore, we propose that trans-generational immune priming in Lepidoptera can be mediated by the maternal transfer of bacteria or bacterial fragments to the developing eggs.
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沃尔巴克氏体Wolbachia是广泛分布于节肢动物体内的共生微生物,可通过宿主卵的细胞质传递给子代.Wolbachia通过多种方式调控其宿主的生殖活动,包括细胞质不亲和、孤雌生殖、雌性化、杀雄性和增强雄性或雌性的生殖力.通过这些调控作用促进其在宿主种群内的广泛传播.文章简要综述Wolbachia对宿主的生殖调控作用、水平传播、Wolbachia基因和应用方面的研究.
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沃尔巴克氏体Wolbachia是广泛分布于节肢动物体内的共生微生物,可通过宿主卵的细胞质传递给子代.Wolbachia通过多种方式调控其宿主的生殖活动,包括细胞质不亲和、孤雌生殖、雌性化、杀雄性和增强雄性或雌性的生殖力.通过这些调控作用促进其在宿主种群内的广泛传播.文章简要综述Wolbachia对宿主的生殖调控作用、水平传播、Wolbachia基因和应用方面的研究.
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URLPMID:12386340 [本文引用: 1]
The adzuki bean beetle, Callosobruchus chinensis, is triple-infected with distinct lineages of Wolbachia endosymbiont, wBruCon, wBruOri, and wBruAus, which were identified by their wsp (Wolbachia surface protein) gene sequences. Whereas wBruCon and wBruOri caused cytoplasmic incompatibility of the host insect, wBruAus did not. Although wBruCon and wBruOri were easily eliminated by antibiotic treatments, wBruAus persisted over five treated generations and could not be eliminated. The inheritance pattern of wBruAus was, surprisingly, explained by sex-linked inheritance in male-heterozygotic organisms, which agreed with the karyotype of C. chinensis (2n = 20, XY). Quantitative PCR analysis demonstrated that females contain around twice as much wsp titer as males, which is concordant with an X chromosome linkage. Specific PCR and Southern blot analyses indicated that the wBruAus-bearing strain of C. chinensis contains only a fraction of the Wolbachia gene repertoire. Several genome fragments of wBruAus were isolated using an inverse PCR technique. The fragments exhibited a bacterial genome structure containing a number of ORFs typical of the -proteobacteria, although some of the ORFs contained disruptive mutations. In the flanking region of ftsZ gene, a non-long terminal repeat (non-LTR) retrotransposon sequence, which is typical of insects but not found from bacteria, was present. These results strongly suggest that wBruAus has no microbial entity but is a genome fragment of Wolbachia endosymbiont transferred to the X chromosome of the host insect.
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随着测序技术的革新和多种组学综合分析方法的应用,昆虫基因组学研究领域得到了迅速的发展.目前,我国昆虫学家已经发表了家蚕Bombyx mori、小菜蛾Plutella xylostella、飞蝗Locusta migratoria榕小蜂Ceratosolen solmsi、褐飞虱Nilaparvata lugens、柑橘凤蝶Papilio xuthus、烟粉虱Bemisia tabaci等多种昆虫基因组图谱,同时在比较基因组学、功能基因组学、生物信息学以及基因编辑等研究领域也取得了突出的成绩.本文主要综述了近五年我国昆虫基因组学的重要进展,并提出了未来在数据分析、团队合作和基因操作等领域面临的挑战.
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随着测序技术的革新和多种组学综合分析方法的应用,昆虫基因组学研究领域得到了迅速的发展.目前,我国昆虫学家已经发表了家蚕Bombyx mori、小菜蛾Plutella xylostella、飞蝗Locusta migratoria榕小蜂Ceratosolen solmsi、褐飞虱Nilaparvata lugens、柑橘凤蝶Papilio xuthus、烟粉虱Bemisia tabaci等多种昆虫基因组图谱,同时在比较基因组学、功能基因组学、生物信息学以及基因编辑等研究领域也取得了突出的成绩.本文主要综述了近五年我国昆虫基因组学的重要进展,并提出了未来在数据分析、团队合作和基因操作等领域面临的挑战.
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URLPMID:28490635 [本文引用: 1]
Forkhead box O (FOXO) functions as the terminal transcription factor of the insulin signaling pathway and regulates multiple physiological processes in many organisms, including lifespan in insects. However, how FOXO interacts with hormone signaling to modulate insect growth and development is largely unknown. Here, using the transgene-based CRISPR/Cas9 system, we generated and characterized mutants of the silkworm Bombyx mori FOXO ( BmFOXO ) to elucidate its physiological functions during development of this lepidopteran insect. The BmFOXO mutant (FOXO-M) exhibited growth delays from the first larval stage and showed precocious metamorphosis, pupating at the end of the fourth instar (trimolter) rather than at the end of the fifth instar as in the wild-type (WT) animals. However, different from previous reports on precocious metamorphosis caused by juvenile hormone (JH) deficiency in silkworm mutants, the total developmental time of the larval period in the FOXO-M was comparable with that of the WT. Exogenous application of 20-hydroxyecdysone (20E) or of the JH analog rescued the trimolter phenotype. RNA-seq and gene expression analyses indicated that genes involved in JH degradation but not in JH biosynthesis were up-regulated in the FOXO-M compared with the WT animals. Moreover, we identified several FOXO-binding sites in the promoter of genes coding for JH-degradation enzymes. These results suggest that FOXO regulates JH degradation rather than its biosynthesis, which further modulates hormone homeostasis to control growth and development in B. mori . In conclusion, we have uncovered a pivotal role for FOXO in regulating JH signaling to control insect development.
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飞蝗是一种重大农业害虫,其分布范围几乎覆盖了东半球的整个温带和热带地区。由于飞蝗的远距离迁移习性,不同地理种群间的基因交流非常复杂。基于形态学特征,飞蝗曾被建议划分为13个亚种。然而,这些亚种的分类地位一直存有争议,不同亚种或地理种群间的亲缘关系也不十分清楚。近年来飞蝗分子谱系地理学研究的开展,尤其是基于线粒体基因组序列的研究,为飞蝗的种群遗传关系提供了全新的观点。线粒体基因组研究结果表明,飞蝗起源于非洲,通过南北2个主要线路扩散到整个旧世界。分子证据证明世界范围内仅有2个飞蝗亚种,分布于欧亚大陆温带地区的飞蝗属于亚洲飞蝗Locustamigratoria migratoria,分布于非洲、大洋洲和欧亚大陆南部地区的飞蝗属于非洲飞蝗L.m.migratorioides,所有其它的亚种和地理宗都是这2个亚种的地理种群。文中就飞蝗的种群遗传学、亚种分类的研究历史和研究进展进行了综述,还就许多飞蝗地理种群的谱系地理关系进行了讨论。
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URL [本文引用: 2]
飞蝗是一种重大农业害虫,其分布范围几乎覆盖了东半球的整个温带和热带地区。由于飞蝗的远距离迁移习性,不同地理种群间的基因交流非常复杂。基于形态学特征,飞蝗曾被建议划分为13个亚种。然而,这些亚种的分类地位一直存有争议,不同亚种或地理种群间的亲缘关系也不十分清楚。近年来飞蝗分子谱系地理学研究的开展,尤其是基于线粒体基因组序列的研究,为飞蝗的种群遗传关系提供了全新的观点。线粒体基因组研究结果表明,飞蝗起源于非洲,通过南北2个主要线路扩散到整个旧世界。分子证据证明世界范围内仅有2个飞蝗亚种,分布于欧亚大陆温带地区的飞蝗属于亚洲飞蝗Locustamigratoria migratoria,分布于非洲、大洋洲和欧亚大陆南部地区的飞蝗属于非洲飞蝗L.m.migratorioides,所有其它的亚种和地理宗都是这2个亚种的地理种群。文中就飞蝗的种群遗传学、亚种分类的研究历史和研究进展进行了综述,还就许多飞蝗地理种群的谱系地理关系进行了讨论。
URL [本文引用: 1]
天敌瓢虫常在农业生产的生物防治中被广泛引进和使用。这种使用过程往往会导致天敌瓢虫在遗传水平的改变,并最终影响到其生物防治的使用效果和本地生态多样性。对天敌瓢虫种群遗传学的研究,有助于我们认识甚至预测这种遗传改变的规律和生态机制,从而为生物防治计划的优化提供理论基础。本文介绍了种群遗传学的研究方法,分析在生物防治中促进天敌瓢虫遗传改变的因素,以及几种常见的天敌瓢虫种群演变情况,并讨论种群遗传学在天敌瓢虫研究的未来方向。
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URL [本文引用: 1]
天敌瓢虫常在农业生产的生物防治中被广泛引进和使用。这种使用过程往往会导致天敌瓢虫在遗传水平的改变,并最终影响到其生物防治的使用效果和本地生态多样性。对天敌瓢虫种群遗传学的研究,有助于我们认识甚至预测这种遗传改变的规律和生态机制,从而为生物防治计划的优化提供理论基础。本文介绍了种群遗传学的研究方法,分析在生物防治中促进天敌瓢虫遗传改变的因素,以及几种常见的天敌瓢虫种群演变情况,并讨论种群遗传学在天敌瓢虫研究的未来方向。
URL [本文引用: 1]
考查分析了东亚飞蝗精巢细胞减数分裂各主要时期的特征及分裂高峰期,为昆虫染色体结构、功能及进化研究提供标本材料,为蝗虫染色体的后续研究奠定了基础,也为生物遗传实验教学提供一种简单易行的方法。本实验采用每只活体注射0.04%秋水仙素0.1ml、细胞悬液滴片的方法,对东亚飞蝗的精巢细胞进行染色体制片。实验观察到东亚飞蝗精巢细胞减数分裂Ⅰ、Ⅱ各主要时相的鲜明特征,双线期同源染色体的四分体结构明显,浓缩期染色体形状多种,8月中旬是制作东亚飞蝗减数分裂标本的最佳时期。
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URL [本文引用: 1]
考查分析了东亚飞蝗精巢细胞减数分裂各主要时期的特征及分裂高峰期,为昆虫染色体结构、功能及进化研究提供标本材料,为蝗虫染色体的后续研究奠定了基础,也为生物遗传实验教学提供一种简单易行的方法。本实验采用每只活体注射0.04%秋水仙素0.1ml、细胞悬液滴片的方法,对东亚飞蝗的精巢细胞进行染色体制片。实验观察到东亚飞蝗精巢细胞减数分裂Ⅰ、Ⅱ各主要时相的鲜明特征,双线期同源染色体的四分体结构明显,浓缩期染色体形状多种,8月中旬是制作东亚飞蝗减数分裂标本的最佳时期。
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URL [本文引用: 1]
Chromosome preparations were made from testis tissue of the beet armyworm ((Spodoptera exigua H眉bner)) with airdry method. The morphological characteristics and behaviors of the chromosomes at various phases of mitosis and meiosis were studied. The chromosome number of the beet armyworm was determined as n=31. All chromosomes have diffuse centromeres, and two chromosomes have secondary constriction. Chromosomes interlockings occur during the late zygotene. The synaptonemal complexes stretch gradually from the early pachytene to late pachytene. During the diakinesis the synaptonemal complexes showed rings, crossed or end_to-end configurations.
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URL [本文引用: 2]
react-text: 284 Two new species of the genus Neoperla are described from Yunnan Province, China: Neoperla lihuae Li & Murányi, sp. nov. and Neoperla yanlii Li & Wang, sp. nov. They are compared with related congeners. Brief comments on the taxonomy of N. cavaleriei (Navás, 1922), N. limbatella Navás, 1933, N. obscurofulva Wu, 1962 and N. lui Du, 2004 are also presented. /react-text react-text: 285 /react-text
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利用实验室保存的果蝇特定突变品系,设计了从基因组的提取到基因分型的系列实验教学.针对果蝇体色突变的2个基因,建立基因扩增、酶切、凝胶检测方法,判定2个体色突变的基因型,利用基因型回推被检果蝇的亲本组合.实验对学生进行分子遗传实验技术的基本训练,同时,让学生从分子层面理解等位基因相互作用和基因间的相互作用关系,并加深学生对表型选择与基因型选择的差别的理解.
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URL [本文引用: 1]
利用实验室保存的果蝇特定突变品系,设计了从基因组的提取到基因分型的系列实验教学.针对果蝇体色突变的2个基因,建立基因扩增、酶切、凝胶检测方法,判定2个体色突变的基因型,利用基因型回推被检果蝇的亲本组合.实验对学生进行分子遗传实验技术的基本训练,同时,让学生从分子层面理解等位基因相互作用和基因间的相互作用关系,并加深学生对表型选择与基因型选择的差别的理解.
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URL [本文引用: 1]
URLMagsci [本文引用: 1]
【目的】Gal80<sup>ts</sup>与Gal4组合驱动UAS转基因表达是黑腹果蝇<em>Drosophila melanogaster</em>研究中常用的转基因过表达遗传学工具,通过温度控制实现对UAS转基因表达的灵活开关。Gal80<sup>ts</sup>是一种温度敏感型蛋白,低温下(18℃)与Gal4蛋白结合并抑制其转录活力,高温下(29℃)解除对Gal4的抑制,从而允许Gal4结合UAS位点,启动UAS转基因的表达。但是从18~29℃的开关只能强烈过表达UAS转基因,而不能灵活调控转基因的表达水平。本实验系统研究一系列温度下转基因的表达水平,从而实现该体系对转基因的表达水平的灵活控制。【方法】以果蝇翅芽这一常用器官组织为研究模型,以2种Gal4品系(dpp-Gal4和en-Gal4,分别由<em>decapentaplgic</em>和<em>engrailed</em>基因的启动子驱动)分别与tub-Gal80<sup>ts</sup>(微管蛋白基因<em>tubulin</em>启动子驱动)基因重组后,再分别与UAS-wg(<em>wingless</em>)转基因品系杂交;在一系列温度(18,25, 27.5, 28, 28.5和30℃)下进行子代幼虫培养,通过免疫组化染色揭示并量化分析转基因wg在3龄幼虫翅芽上的表达水平。【结果】18~25℃培养条件下,Gal80<sup>ts</sup>与Gal4组合系统中的UAS转基因不能表达;30℃时培养,转基因强烈地过表达;在25~30℃区间内,随着温度升高, 转基因表达水平逐渐上升。【结论】在25~30℃之间的温度调控可以实现对Gal80<sup>ts</sup>与Gal4组合系统中的UAS转基因表达水平的调控。本研究结果对调控转基因表达程度有重要价值。
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URLMagsci [本文引用: 1]
【目的】Gal80<sup>ts</sup>与Gal4组合驱动UAS转基因表达是黑腹果蝇<em>Drosophila melanogaster</em>研究中常用的转基因过表达遗传学工具,通过温度控制实现对UAS转基因表达的灵活开关。Gal80<sup>ts</sup>是一种温度敏感型蛋白,低温下(18℃)与Gal4蛋白结合并抑制其转录活力,高温下(29℃)解除对Gal4的抑制,从而允许Gal4结合UAS位点,启动UAS转基因的表达。但是从18~29℃的开关只能强烈过表达UAS转基因,而不能灵活调控转基因的表达水平。本实验系统研究一系列温度下转基因的表达水平,从而实现该体系对转基因的表达水平的灵活控制。【方法】以果蝇翅芽这一常用器官组织为研究模型,以2种Gal4品系(dpp-Gal4和en-Gal4,分别由<em>decapentaplgic</em>和<em>engrailed</em>基因的启动子驱动)分别与tub-Gal80<sup>ts</sup>(微管蛋白基因<em>tubulin</em>启动子驱动)基因重组后,再分别与UAS-wg(<em>wingless</em>)转基因品系杂交;在一系列温度(18,25, 27.5, 28, 28.5和30℃)下进行子代幼虫培养,通过免疫组化染色揭示并量化分析转基因wg在3龄幼虫翅芽上的表达水平。【结果】18~25℃培养条件下,Gal80<sup>ts</sup>与Gal4组合系统中的UAS转基因不能表达;30℃时培养,转基因强烈地过表达;在25~30℃区间内,随着温度升高, 转基因表达水平逐渐上升。【结论】在25~30℃之间的温度调控可以实现对Gal80<sup>ts</sup>与Gal4组合系统中的UAS转基因表达水平的调控。本研究结果对调控转基因表达程度有重要价值。
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血型是人类日常生活中非常常见的一种遗传表型,拥有丰富的遗传学内涵.随着科技的发展和技术的更新,血型的检测也越来越快速、精细.在本科生遗传学实验教学中引入ABO血型的分子分型实验,是引导学生思考生活常识、加强遗传学思维训练的一种有效的教学内容,通过教学实践中的不断优化,并依据Science杂志上发表的"重复提取"比"细化学习"更能促进学习的发生和记忆的保持原则,针对性地设计实验教学方案,注重学生自我测试能力的培养,同时加入新的分子信标技术知识,既传承了经典,又紧跟时代发展,使经典实验与新技术实现非常契合的融合.该实验贴近生活,大大激发了学生参与实验的积极性和对科研的兴趣,而且易于根据教学的对象调整教学内容和理论深度,对于培养学生的遗传学分析思想和科学思维素质能够发挥很好的典范作用.
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URL [本文引用: 1]
血型是人类日常生活中非常常见的一种遗传表型,拥有丰富的遗传学内涵.随着科技的发展和技术的更新,血型的检测也越来越快速、精细.在本科生遗传学实验教学中引入ABO血型的分子分型实验,是引导学生思考生活常识、加强遗传学思维训练的一种有效的教学内容,通过教学实践中的不断优化,并依据Science杂志上发表的"重复提取"比"细化学习"更能促进学习的发生和记忆的保持原则,针对性地设计实验教学方案,注重学生自我测试能力的培养,同时加入新的分子信标技术知识,既传承了经典,又紧跟时代发展,使经典实验与新技术实现非常契合的融合.该实验贴近生活,大大激发了学生参与实验的积极性和对科研的兴趣,而且易于根据教学的对象调整教学内容和理论深度,对于培养学生的遗传学分析思想和科学思维素质能够发挥很好的典范作用.
URL [本文引用: 2]
随着遗传学学科的发展,实验教学既要传承经典又要紧跟前沿,如何将经典实验与新技术有效的相互结合,是当前教学改革急需解决的挑战任务。RNA干扰技术比较经典,技术成熟;CRISPR/Cas9敲除技术是较为前沿的技术,在教学改革实践中将这两项非常重要的反向遗传学技术相结合,开展比较性教学,并引导学生展开讨论,后期再进行拓展延伸,分别从DNA、mRNA和蛋白质三个水平上检测分析RNA干扰和CRISPR/Cas9敲除技术的区别,既可让学生领略到经典技术的美妙之处,又可接触到最新的科研技术。整个实验设计完整,深受学生欢迎,大大提高了教学效果。
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URL [本文引用: 2]
随着遗传学学科的发展,实验教学既要传承经典又要紧跟前沿,如何将经典实验与新技术有效的相互结合,是当前教学改革急需解决的挑战任务。RNA干扰技术比较经典,技术成熟;CRISPR/Cas9敲除技术是较为前沿的技术,在教学改革实践中将这两项非常重要的反向遗传学技术相结合,开展比较性教学,并引导学生展开讨论,后期再进行拓展延伸,分别从DNA、mRNA和蛋白质三个水平上检测分析RNA干扰和CRISPR/Cas9敲除技术的区别,既可让学生领略到经典技术的美妙之处,又可接触到最新的科研技术。整个实验设计完整,深受学生欢迎,大大提高了教学效果。
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