封面说明

<正>家蚕(Bombyx mori)遗传资源丰富,是遗传学研究的极佳材料。由于色素在皮肤中的沉积形成繁多的斑纹类型,其中普通斑被作为幼虫斑纹的正常型(+)。普通斑(+)在第2胸节背面有眼状纹,第2腹节背面有1对半月纹,第5腹节背面有1对星状纹。最近,本课题组在家蚕素斑品种中发现了酷似鹑斑的突变体,褐色类鹑斑(Brown quail-like,q-l~b)和紫色类鹑斑(Purple quail-like,q-l~p)。它们的半月纹和星状纹正常,但无眼状纹,蚕体背面及侧面有纵向波纹状斑纹分布,侧面波纹较长,背面波纹第5腹节后短而密。封面图片为5龄期褐色类鹑斑幼虫图,其稚蚕期体色呈褐色。遗传分析表明褐色类鹑斑(q-l~b)与紫色类     

天宫二号航天蚕后代小茧突变体sc的发现与基因定位

【目的】从2016年天宫二号空间实验室经历33 d后返回的1头成活“秋丰×白玉”杂交后代雌蚕Bombyx mori与地面“白玉”雄蚕交配的后代个体中,发现有结小茧突变体,进而分离并建立了飞天蚕(space silkworm)正常茧品系TG和小茧突变体品系sc。本研究通过对sc进行遗传分析和基因定位,旨在揭示产生小茧突变体的基因。【方法】对TG和sc进行表型分析;以sc, TG和正常大茧品系0223V1为试验材料,组配(sc♀×0223V1♂)F₁及回交群体BC₁F——(sc♀×0223V1♂)F₁♀×sc♂和BC₁M——sc♀×(sc♀×0223V1♂)F₁♂。以sc, 0223V1和F₁基因组DNA为模板,每个连锁群随机选10个SSR引物进行PCR扩增,筛选多态性SSR标记。利用雌性家蚕减数分裂染色体不交换的特点,用BC₁F确定sc基因所属连锁群;再根据家蚕SSR分子标记连锁图谱,用BC1M进行基因定位。【结果】表型分析表明sc幼虫体型小于TG幼虫的,蚕茧重约为TG的1/2。遗传分析表明突变受一对隐性基因sc控制;基因定位结果表明该基因位于家蚕基因组第3连锁群S2930-363和S2930-289 SSR标记之间,物理距离为684 kb,包含33个候选基因。【结论】飞天蚕小茧突变受位于家蚕基因组第3连锁群的一对隐性基因sc控制。     

利用计算机视觉技术量化解析食物颜色与斜纹夜蛾幼虫体色变化的关系

【目的】为了明确食物颜色对不同日龄昆虫体色的影响,并推广利用计算机视觉研究昆虫体色的技术。【方法】本研究以斜纹夜蛾Prodenia litura幼虫为实验材料,采用计算机定量分析的方法,对取食不同颜色型人工饲料的斜纹夜蛾幼虫头部、胸部斑纹、胸腹部和背中线的红色(R)、绿色(G)、蓝色(B)和明度(L)值进行了定量化分析。【结果】结果表明:幼虫的斑纹、胸腹部背面及侧面主色和背中线的R,G,B和L值随日龄增加而下降;头部R,G,B和L值在1-3日龄增加,后随日龄的增加而下降。幼虫体色变化也受食物颜色的影响,以对1-7日龄的影响为最大;红色型食物r∶g∶b=(128~251)∶(3~129)∶(6~96)对幼虫各部位体色的影响大于黄色、绿色和紫色的食物;幼虫取食不同颜色型食物后,各部位的变异系数大小依次为:斑纹胸腹部头部背中线。最后,建立了幼虫体色与食物色彩r,g,b值及日龄的回归方程。【结论】斜纹夜蛾幼虫体色受到食物颜色的影响,且在低龄时更为显著。     

一种深色型粘虫成虫体色突变体的遗传分析

【目的】在粘虫Mythimna separate(Walker)常规饲养种群和室外监测中发现一种成虫体色突变体,本文主要研究其遗传模式及进行表型观察。【方法】用杂交实验的方法对该突变体进行观察研究。【结果】与正常型相比,该突变体的腹、翅颜色等形态特征与正常型有显著的不同;卵、幼虫的颜色与正常型的没有明显的区别;蛹的颜色前期没什么区别,临近羽化时表现为颜色较深。正常型与突变体正反交F1代均为正常型,F2代正常型和突变体分离比例为3.24︰1,回交比例为1.18︰1,F2代突变体自交,后代全为突变体。【结论】该突变体的遗传符合孟德尔的遗传规律,属于常染色体上单基因控制的隐性遗传性状。本项研究结果可以为粘虫的遗传防治、进化上的环境适应性及内在分子机制研究提供参考。     

玉米sk-A7110突变体的鉴定与基因定位

柱头是玉米的主要性器官,其正常发育与形态建成对种子的繁殖和产量具有决定作用。本实验室发现一个雌穗发育异常的自然突变体sk-A7110,该突变体雌穗的柱头完全缺失,无法授粉结实。遗传分析表明,sk-A7110突变体的柱头缺失性状属于隐性性状,受1对隐性核基因控制。利用集团分离分析法将控制对应野生型性状的SKA7110基因定位在2号染色体短臂上,位于物理距离约255kb的SAG21与IDP1453标记之间,研究工作为SKA7110基因的克隆与功能分析奠定了基础。     

水稻花器官突变体apl (abnormal palea and lodicules) 的表型分析与基因初定位

水稻(Oryza sativa)是重要的粮食作物, 其花器官的正常起始及形态建成直接影响水稻的产量。为了深入分析水稻小花发育的调控机理, 从已构建的水稻EMS诱变突变体库中筛选获得了一个花器官异常发育的突变体apl (abnormal palea and lodicules)。与野生型相比, apl突变体小花的内稃膨大, 浆片伸长或转换成稃状结构, 雄蕊数目减少, 表明APL基因可能参与调控水稻内稃、浆片和雄蕊等多轮花器官属性的建成。遗传学分析表明, 该突变体性状受1个隐性单基因控制。通过图位克隆, 将APL基因初步定位于1号染色体上。该工作为深入研究APL基因在水稻花器官形态建成中的作用机制奠定了基础。     

斑痣悬茧蜂在黏虫寄主体内与中红侧沟茧蜂竞争下的存活和发育表现

【目的】不同种寄生蜂在同一小生境中可能寄生同一共享寄主。本研究旨在为认识寄生蜂种间互作关系,并为科学评价寄生性天敌控害效应提供依据。【方法】在室内以单寄生性斑痣悬茧蜂Meteorus pulchricornis(Wesmael)和中红侧沟茧蜂Microplitis mediator(Halidy)及其寄主黏虫Mythimna separata(Walker)低龄幼虫为材料,以寄生顺序和间隔时间为因素进行种间寄生竞争效应实验,观察比较两种蜂的存活和斑痣悬茧蜂子代的发育历期、体型大小和寿命等发育参数。【结果】不同寄生顺序和间隔时间组合处理下斑痣悬茧蜂子代蜂存活率始终高于中红侧沟茧蜂,且先寄生的斑痣悬茧蜂子代存活率高于后寄生的蜂,提前24 h寄生的斑痣悬茧蜂子代存活率可高达96.7%。当斑痣悬茧蜂先于中红侧沟茧蜂寄生时,其子代幼虫发育历期比单独寄生(对照)时显著延长;当后于中红侧沟茧蜂寄生时,其子代幼虫发育历期与单独寄生时无显著差异。各竞争处理下,斑痣悬茧蜂子代成虫寿命均长于单独寄生的子代成虫;子代成虫后足胫节长度与单独寄生相比明显缩短。【结论】结果说明,斑痣悬茧蜂在黏虫低龄幼虫体内与中红侧沟茧蜂的竞争中占有优势,但竞争对斑痣悬茧蜂子代生长发育具有负面影响。     

斑痣悬茧蜂的寄主种间选择性及其子代蜂发育适合度表现

为检验基于经典搜寻理论的最优膳食模型的预测——产卵雌蜂应该选择最适于子代蜂发育的寄主种进行产卵,本研究以斑痣悬茧蜂(Meteorus pulchricornis)及其寄主斜纹夜蛾(Spodoptera litura)和粘虫(Mythimna separata)的幼虫为材料,在控制寄主体型大小和龄期影响的基础上,分别在体型大小相近和日龄相同的3个水平上观察了斑痣悬茧蜂对2种寄主幼虫的选择偏好,并观察了子代蜂生长发育适应度表现。在观察期(1h)内,当2种寄主幼虫的体型相近或者龄期相同的情况下,斑痣悬茧蜂对粘虫的产卵器刺扎次数以及寄生率(用结茧率表示)均高于斜纹夜蛾;而在斜纹夜蛾幼虫体内发育出的子代蜂茧重和体型均大于粘虫,成蜂寿命无显著差异。最后,对斑痣悬茧蜂的寄主选择和子代发育表现不一致现象进行了讨论。     

控制水稻叶绿体发育基因OsALB23的定位

叶绿体的正常发育是高等植物进行光合作用的前提条件。通过电镜观察,我们发现水稻白化突变体Osalb23的叶绿体发育缺陷,内部缺少正常类囊体片层结构。遗传学分析表明该突变体属于单位点隐性突变。利用图位克隆的方法,我们将基因定位于水稻第二条染色体分子标记R2M501和R2M502之间约280kb范围内。通过生物信息学软件预测,这段区间包括6个叶绿体蛋白基因。     

ST273是拟南芥绒毡层和小孢子发育的必需基因

绒毡层在拟南芥花药花粉发育过程中具有重要作用,包括分泌降解胼胝质的胼胝质酶、为花粉壁的形成提供原料以及为小孢子发育提供营养物质.本文通过对拟南芥雄性不育突变体st273的分析,研究了ST273基因在花药花粉发育过程中的功能.st273是通过T-DNA插入诱变野生型拟南芥得到的一株突变体,遗传分析表明st273是单隐性核基因控制的.利用图位克隆的方法对不育基因ST273进行了定位,结果表明ST273基因与拟南芥第三条染色体上分子标记CIW11连锁.生物信息学分析发现该分子标记附近有一个调控花粉发育的基因TDF1.测序分析结果表明在st273突变体中,TDF1基因第三个外显子上459位的碱基发生了由G459变成了A459的单碱基变化,导致ST273基因该位点提前终止突变.等位分析结果表明st273与tdf1是等位突变体.st273突变体营养生长期发育正常,但生殖生长发育出现异常.亚历山大染色结果显示st273突变体花药中没有花粉.组织切片观察结果表明,突变体花药绒毡层异常肥大且空泡化,四分体不能正常释放小孢子,最终无法形成花粉.这些结果揭示了ST273蛋白质参与调控了绒毡层和小孢子发育过程.     

Caterpillar color patterns are determined by a two‐phase melanin gene prepatterning process: new evidence from tan and laccase2

SUMMARY The larval color patterns in Lepidoptera exhibit splendid diversity, and identifying the genes responsible for pigment distribution is essential to understanding color‐pattern evolution. The swallowtail butterfly, Papilio xuthus, is a good candidate for analyzing marking‐associated genes because its body markings change dramatically at the final molt. Moreover, the silkworm Bombyx mori is most suitable for identification of lab‐generated color mutants because genome information and many color mutants are available. Here, we analyzed the expression pattern of 10 melanin‐related genes in P. xuthus, and analyzed whether these genes were responsible for Bombyx larval color mutants. We found that seven genes correlated strongly with the stage‐specific larval cuticular markings of P. xuthus, suggesting that, compared with Drosophila, more genes showed marking specificity in lepidopteran larvae. We newly found that the expression of both tan and laccase2 is strongly correlated with the larval black markings in both P. xuthus and B. mori. The results of F2 linkage analysis and mutant analysis strongly suggest that tan is the responsible gene for Bombyx larval color mutant rouge, and that tan is important in emphasizing black markings of lepidopteran larvae. Detailed comparison of temporal and spatial expression patterns showed that larval cuticular markings were regulated at two different phases. Marking‐specific expression of oxidizing enzymes preceded the marking‐specific expression of melanin synthesis enzymes at mRNA level, which is the reverse of the melanin synthesis step.     

The genetics of colour-patterns in the grasshopper Chorthippus brunneus

Several alleles were found to determine the colour of the dorsal pronotum in Chorthippus brunneus; there was evidence for at least two loci ( C and V ). Brown ( C^B )was the universal recessive and green ( C^C ) was dominant to all other colours. The white allele ( C^W )was codominant with green( C^G )and purple ( C^P ). Wing-patterns were determined by a separate, probably linked locus ( W ). A dominant plain wing-pattern ( W^P ) was associated with colours other than brown. Striped( W^S )and mottled( W^mo ) were codominant and a plain recessive allele ( W^P ) was also found. All three alleles were associated with the brown phenotype. A purple-sided allele ( S^Pu ) was sometimes obmd with C^pu.. S ^Pu was dominant to brown sides ( S^B ), A series of markings on the dorsal and lateral pronotum ( linea intermedia, fascia postocularis, linea media, carina media and zona lateralis ) were investigated and found to be controlled at separate loci which may be linked to W . These characters were expressed by dominant alleles.
Epistatic effects by modifier loci were shown to have an important effect on the determination of wing phenotype. Allele Wo⁺ , for example, suppressed the stripe-wing pattern, linea media, carina media and zona lateralis .
It was concluded that colour patterns appear to be under genetic control and that dominant alleles were rare in the wild. Changes in shades of colours were shown to be age-dependent and minor.     

Two New Species of Afronurus (Ephemeroptera: Heptageniidae) from Vietnam

ABSTRACT Two new species of the heptageniid mayfly genus Afronurus Lestage, Afronurus meo sp. n. and Afronurus mnong sp. n., are described from Vietnam with line-drawings of key characters. The larvae of A. meo can be characterized by rowed minute spines in the posterior margin of the abdominal terga 1-9 and distinct markings on anterior head, dorsal femora, and abdominal terga. The larvae of A. mnong can be characterized by scattered simple stout setae on the anterior margin and dorsal surface of femora, rowed acute spines on the posterior margin of abdominal terga 1-9, and plain brown body color. Their diagnoses, material data, distributions, and habitat and biological data are provided.     

Quail neural crest cells cannot read positional values in the dorsal trunk feathers of the chicken embryo

Summary If quail neural crest cells are grafted to the chick, they migrate into the feathers of the host and produce melanin pigment. In one study, the dorsal trunk feathers of the chimaera were found to have quail-like pigment patterns. This was interpreted in terms of a positional information model. By contrast, in another study it was found that pigment patterns in the wing plumage of the chimaera bore little or no resemblance to the quail, showing instead a rather uniform, dark pigmentation. This was interpreted in terms of a prepattern in the ectoderm. This striking difference in results could be because the wing and trunk plumages have their pigment patterns specified in different ways. We have examined this possibility by making detailed maps of the dorsal trunk plumage of the normal quail and the quail-chick chimaera. Using this novel technique, we can accurately record the secondary pigment patterns in the embryonic down plumage. In the quail there are well-defined, longitudinal stripes running down the back, whereas the chimaera shows rather uniform, dark pigment in this area. There is little or no indication of stripes and some chimaerae develop asymmetric, mottled patterns. Grafts to the cephalic region also produce uniform pigmentation with no quail-like patterning. These findings indicate that neural crest cells cannot read positional values in the feathers of another species.     

Pigment pattern formation in the quail mutant of the silkworm, Bombyx mori: parallel increase of pteridine biosynthesis and pigmentation of melanin and ommochromes

The larval pigment pattern in the silkworm, Bombyx mori, is formed by melanin, ommochromes and pteridines. During development all these pigments are synthesized autonomously, and possibly also with mutual interaction between them, to yield unique pigment patterns. In order to find the key trigger for such pigment pattern formation, developmental changes in pteridine biosynthesis were studied using the quail mutant (q/q), which has darker larval marks formed by melanin and an abundance of ommochromes in the integument. In the current study, emphasis has been placed on the analysis of GTP-cyclohydrolase I (GTP-CH I), which is a key enzyme for the biosynthesis of pteridines, during the development of the silkworm. Results of Northern blotting showed that in the quail mutant strong signals of GTP-CH I mRNA appeared around each period of ecdysis, while no such signals appeared in the background strain (+q/q) used. Also, both GTP-CH I activities and pteridine content were higher in the quail mutant compared with the background strain. These results strongly suggest that pteridine biosynthesis is closely linked to the formation of melanin and ommochromes. It is also suggested here that in the silkworm a recessive gene (q) may be involved in the regulation of its pigment pattern formation.     

普通齿蛉和单斑巨齿蛉(广翅目:齿蛉科)卵块及1龄幼虫形态学研究

本文以普通齿蛉Neoneuromus ignobilis Navás,1932和单斑巨齿蛉Acanthacorydalis unimaculata Yang et Yang,1986为例,描述和比较了广翅目齿蛉科齿蛉属和巨齿蛉属的卵块及1龄幼虫形态特征.结果显示普通齿蛉与单斑巨齿蛉的卵块和1龄幼虫在形态上有着较大差异:普通齿蛉卵块约为单斑巨齿蛉卵块的3/4;普通齿蛉卵粒约为单斑巨齿蛉卵粒的2/3,卵粒都呈圆柱形,差异不大;普通齿蛉外层白色覆盖物厚度是单斑巨齿蛉的2～3倍.普通齿蛉卵块为单个附着在芦苇叶上,形状有4种类型,分别为椭圆形、螺形、卵圆形、圆形,在所有样本中其占比分别依次为47.1％、9.8％、17.6％和25.5％;单斑巨齿蛉卵块多为数个相连附着在桥底,卵壳薄且最外层卵粒向外翘起,使其表面如突起均匀地分布在卵壳表面.普通齿蛉1龄幼虫腹部背面白色的线状裸露区较稳定,且8对气管鳃靠近末端都有褐色和黄色的斑纹,而单斑巨齿蛉1龄幼虫腹部背面呈深褐色,腹部背面裸露区和颜色分布不稳定,气管鳃无花斑;两种1龄幼虫腹部两侧均都无毛簇.这些数据资料不仅丰富了广翅目昆虫的相关知识,而且为其产业化应用提供了参考.     

Platinum coat color locus in the deer mouse

Platinum coat color in the deer mouse, Peromyscus maniculatus, is an autosomal recessive trait marking a locus, pt, distinct from silver (si), albino (c), blonde (bl), brown (b), and agouti (a). Platinum deer mice are conspicuously pale, with light ears and tail stripe. The pewter trait is allelic with and phenotypically identical to platinum, and represents an independent recurrence of this mutant. The rate of recoveries of coat color mutations from wild deer mice is consistent with available data for recurring mutation rates balanced by strong selection against the recessive phenotype.     

Plumage colour mutations and melanins in the feathers of the Japanese quail: a first comparison

The absorbance of melanin content from dorsal feathers was compared between wild-type Japanese quail and nine other quail plumage colours determined by single mutations in one of seven genes: extended brown ( MC1R ), yellow ( ASIP ), silver ( MITF ), lavender ( MLPH ), roux ( TYRP1 ), imperfect albinism ( SLC45A2 ) and rusty . As compared with wild-type quail, all mutations but extended brown decreased total melanins. The largest decrease was observed in quail with one of the dilution mutations at TYRP1 , MLPH or SLCA45A2 . No difference in eumelanins was found between the 10 plumage colours. Despite visible colour differences, homozygous and heterozygous mutants at MITF , or the two imperfect albino (white) and cinnamon (pale yellow) alleles at SLC45A2, could not be differentiated on the basis of melanins. In contrast, the two white phenotypes caused by mutations at MITF and SLC45A2, or the two reddish plumage colours caused by the roux and rusty non-allelic mutations had different total melanin contents. The results showed that rusty was not likely to be a dilution mutation.