The normal function of a speciation gene, Odysseus, and its hybrid sterility effect

To understand how postmating isolation is connected to the normal process of species divergence and why hybrid male sterility is often the first sign of speciation, we analyzed the Odysseus (OdsH) gene of hybrid male sterility in Drosophila. We carried out expression analysis, transgenic study, and gene knockout. The combined evidence suggests that the sterility phenotype represents a novel manifestation of the gene function rather than the reduction or loss of the normal one. The gene knockout experiment identified the normal function of OdsH as a modest enhancement of sperm production in young males. The implication of a weak effect of OdsH on the normal phenotype but a strong influence on hybrid male sterility is discussed in light of Haldane's rule of postmating isolation.     

海洋酸化对海水青鳉性别分化的影响

以海水青鳉作为研究对象,研究海洋酸化对其性别分化的影响。将刚受精的受精卵置于对照组(CO_2浓度为480×10~(-6))和2个处理组(CO_2浓度分别为1 000×10~(-6)和2 000×10~(-6))的水体中,直到孵化出膜。将出膜后仔鱼饲养在对照组水体中至性成熟,然后通过形态学、组织学和遗传学方法,对每一尾实验鱼进行表现型和基因型的性别鉴定。经形态学判断,发现酸化处理组的雄雌比例显著高于对照组(P0.01)。经形态学观察其第二性征和遗传学性别判断,对照组的青鳉从孵化到性成熟的个体中并未出现基因型和表现型性别不一致的个体,而在2个酸化处理组中,均有基因型为XX而表现型为雄性的个体,即性逆转雄性,性逆转率分别为38.4%和47.5%。     

鸡性分化前抑制雌激素合成对性行为和视前内侧核的影响

 在受精蛋孵化第3天从气室注入100 μl生理盐水或芳香化酶抑制剂(AI),出雏后常规饲养到8月龄性成熟,观察其性行为,检测血清性激素水平,观察下丘脑视前内侧核(POM)形态结构变化。结果发现,AI处理母鸡获得雄性交配行为,血中雌二醇(E2)和睾酮(T)含量发生变化,雄性交配频率与血清T/E2 比呈正相关。1日龄雌雄雏鸡POM细胞大小和形态无明显差异,AI处理后细胞均变大;性反转母鸡POM细胞形态较正常母鸡无明显变化,但细胞密度降低,细胞变小。结果表明,在胚胎期抑制芳香化酶活性可以引起血清性激素水平、性行为雄     

不同pH人工精浆对性逆转金鳟雄鱼精子活力的影响

研究了性逆转金鳟雄鱼（XX,伪雄鱼）精子在不同pH的人工精浆（ artificial seminal plasma,ASP）溶液中的活动情况。结果显示,随着pH的提高精子活力不断增强。伪雄鱼精子在不同ASP—pHs中培养1h后,pH9．5～10．5培养组精子活力超过正常雄鱼精子（XY）活力水平,且正常雄鱼精子与pH8．5～9．5培养组的精子活力不存在显著性差异（P〉0．05）。将金鳟伪雄鱼精液培育在pH8．5～10．5的ASP中,0～180min内,pH10．5中的精子寿命和激活比例都最佳,180min之后的精子寿命超过80s,激活比例在90％以上,显著好于其他pH组（P〈0．05）。在低温储藏12h后,正常雄鱼精子在ASP—pH10．5溶液中寿命时间最长,为（284．05±78．37）S,其次是同等稀释条件下的伪雄鱼精子寿命,其时间为（203．89±43．68）s,正常雄鱼精液原浆精子寿命最短,为（122．19±37．61）s。直接用金鳟伪雄鱼精液受精,发眼率和仔鱼上浮率仅为12．50％和8．77％,而通过pH10．5的ASP培养后,其发眼率和孵化率分别提高到了52％和49．95％。因此,在高pH的ASP中培养金鳟伪雄鱼精子能提高其活力和延长寿命。通过这种处理也能够显著的提高金鳟全雌和全雌三倍不育后代的育苗生产效率。     

Two Dobzhansky-Muller genes interact to cause hybrid lethality in Drosophila

The Dobzhansky-Muller model proposes that hybrid incompatibilities are caused by the interaction between genes that have functionally diverged in the respective hybridizing species. Here, we show that Lethal hybrid rescue (Lhr) has functionally diverged in Drosophila simulans and interacts with Hybrid male rescue (Hmr), which has functionally diverged in D. melanogaster, to cause lethality in F1 hybrid males. LHR localizes to heterochromatic regions of the genome and has diverged extensively in sequence between these species in a manner consistent with positive selection. Rapidly evolving heterochromatic DNA sequences may be driving the evolution of this incompatibility gene.     

Sex chromosome-linked species recognition and evolution of reproductive isolation in flycatchers

Interbreeding between species (hybridization) typically produces unfit offspring. Reduced hybridization should therefore be favored by natural selection. However, this is difficult to accomplish because hybridization also sets the stage for genetic recombination to dissociate species-specific traits from the preferences for them. Here we show that this association is maintained by physical linkage (on the same chromosome) in two hybridizing Ficedula flycatchers. By analyzing the mating patterns of female hybrids and cross-fostered offspring, we demonstrate that species recognition is inherited on the Z chromosome, which is also the known location of species-specific male plumage traits and genes causing low hybrid fitness. Limited recombination on the Z chromosome maintains associations of Z-linked genes despite hybridization, suggesting that the sex chromosomes may be a hotspot for adaptive speciation.     

超级杂交水稻两优培九光抑制差异表达基因的遗传来源

 利用改进的银染mRNA差异显示技术研究杂种超级杂交水稻两优培九及其母本培矮64S和父本9311在光抑制胁迫条件下基因表达的变化，共得到了杂种的167个差异表达基因片段。对这些差异片段进行分类和遗传来源分析表明，杂种光抑制差异表达基因多数为父母本所共有，是母本和父本共同遗传的结果。少数基因表现为母本或父本的单亲特异性，或无明显亲本来源，说明某种未知机制可能参与了光抑制相关基因从亲本到杂种的遗传过程。     

Extensive gene traffic on the mammalian X chromosome

Mammalian sex chromosomes have undergone profound changes since evolving from ancestral autosomes. By examining retroposed genes in the human and mouse genomes, we demonstrate that, during evolution, the mammalian X chromosome has generated and recruited a disproportionately high number of functional retroposed genes, whereas the autosomes experienced lower gene turnover. Most autosomal copies originating from X-linked genes exhibited testis-biased expression. Such export is incompatible with mutational bias and is likely driven by natural selection to attain male germline function. However, the excess recruitment is consistent with a combination of both natural selection and mutational bias.     

三系两系杂交水稻比较研究

三系两系杂交水稻是提高水稻产量最有效的技术。比较三系两系不育系遗传、选育,恢复系选育以及杂交水稻组合选育,对于正确认识三系两系杂种优势具有重要意义。本文综述了三系两系不育系遗传和选育、三系两系恢复系选育、三系两系杂交水稻组合的选育理论与实践等方面进展,并比较了中国水稻数据中心三系两系杂交水稻新组合产量差异。笔者认为三系两系杂交水稻育种技术不同,但两系三系杂交水稻不存在优劣之分。讨论了存在的问题,包括杂交水稻杂种优势机理、三系两系杂交水稻材料创新与育种技术等问题。针对以上问题,建议进一步研究杂交水稻杂种优势机理;加强三系两系亲本改良,聚合更多的优良基因,有更强的配合力;采用常规育种技术结合分子育种,提高三系两系亲本育种效率。     

黄瓜性型遗传与调控的研究

对黄瓜自交纯系及其杂交组合的性型遗传进行分析,进一步验证了全雌基因F和单性花控制基因M的遗传方式,并明确了不同性型自交系的基因型.对黄瓜不同性型植株的药荆处理结果表明,全雌株(FFMMAA)、强雄株(ffMMAA)、两性花株(FFmmAA)、和雄全株(ffmmAA)对乙烯利和AgNO3溶液处理的反应很一致,即乙烯利能诱导产生雌花,AgNO3诱导形成雄花,说明F和M基因的调控途径均与乙烯作用密切相关.     

红麻雄性不育株的发现

 利用家蚕性连锁平衡致死系可实现专养雄蚕的目的。但现行蚕品种缺乏平衡致死系的性别控制基因 ,不能人为控制性别。本文通过一个生物实例 ,介绍一个把家蚕性连锁平衡致死的性别控制基因导入现行品种的方法 ,使现行品种也具有性别控制能力 ,达到生产上专养雄蚕的目的     

Identification of the Sex of Earlier Embryos from Generic Hybrids of Chicken-Quail by Wpkci

In this study, a protocol was developed to identify the sex of earlier embryos of chicken （♂）-quail （♀） hybrids and successfully tested the sex proportion of each period （66-120 h）. We acquired cross bred eggs by artificial insemination, hatched them in the same batch according to the standard hatching condition of chicken, and collected earlier living embryos at 66, 72, 78, 84, 90, 96, 102, 108, 114, and 120 h randomly. We adopted RT-PCR protocol and multiple PCR, made the known sex quail as the external control, employed fl-actin as the internal control, and used primers that were designed according to conservative area of gene Wpkci of quail to identify the sex of earlier hybrid embryos. The results indicated that the primer of Wpkci can be used to identify the sex of hybrid embryos accurately; there were more male than female in earlier embryos, the sex proportion of earlier embryos compared with academic numerical value was significantly different （P〈0.01）, and there was no difference between different periods （P〉0.05）. In the present study, we concluded that a simple, fast, credible and stable protocol to identify the sex of earlier hybrids embryos had been established by using primer of Wpkci; in earlier embryos, the death rate of female was higher than that of male and there was no fluctuant peak.     

小麦高分子量谷蛋白亚基的遗传特性研究

利用聚丙烯酰胺凝胶电泳(SDS-PAGE)方法,在蛋白质水平上对多个亲本及其杂交获得的正反交F1代杂交籽粒进行小麦高分子量谷蛋白亚基(HMW-GS)分析,研究其遗传规律.结果表明:小麦高分子量谷蛋白亚基具有品种特性,表达受遗传控制,不受环境影响;小麦高分子量谷蛋白业基在F1代有些组合呈共显性,有些组合呈倾母性的遗传特性.     

Mosaic histocompatibility of skin grafts from female mice

The histoincompatibility determined by one or more genes on the X chromosome of the mouse effects a complete rejection of skin of the (C57BL/6 female symbol x BALB/c male symbol) F(1) hybrid male grafted onto the reciprocal type F(1) hybrid male, but only an incomplete rejection of either reciprocal type F(1) hybrid female skin, grafted onto the same type of male host. The resulting mosaic survival pattern of the female graft is interpreted as support for the Lyon hypothesis of X-chromosome inactivation.     

两系法杂交水稻研究的进展

两用核雄性不育系是两系法杂交水稻的基础,我国现已育成17个达到规定标准的两用核不育系。根据育性对光温条件的不同反应,它们分为光敏型和温敏型两个基本类型,在生产上均有实用价值,但要因地制宜选用。两系法品种杂交水稻已经研究成功,一批优良组合开始在生产上试种和示范。两系法亚种间杂交水稻的选育也取得了很大的进展。     

Constraints in the evolution of sex ratio adjustment

When the relative fitness of male and female offspring varies with environmental conditions, evolutionary theory predicts that parents should adjust the sex of their offspring accordingly. Qualitative and even quantitative support for this prediction is striking in some taxa but much less convincing in others. Explaining such variation across taxa in the fit of sex ratio theory remains a major challenge. We use meta-analysis to test the role of two constraints in the evolution of sex ratios. Based on analysis of sex ratio skews in birds and wasps, we show that (i) mechanisms of sex determination do not necessarily constrain the evolution of sex ratio adjustment, and (ii) parental ability to predict their offsprings' environment influences the evolution of sex ratio patterns across taxa. More generally, our results show that multiple constraints may determine the precision of adaptation.     

超级杂交稻育种的创新思维与实践

超级杂交稻育种的创新思维提出了超级杂交稻育种三步法设想,即超级亲本选育——超级杂交组合选育——超级杂交制种,并详细阐述了各步骤的标准和实现其目标的技术路线;提出了水稻光温敏不育机理新设想:即水稻光温敏核不育系育性转换是主效不育基因与其位置相近的发育感光基因或(和)发育感温基因相互作用的结果,不育基因位点(微效不育基因)可影响两用核不育系的不育起点温度的高低.按照超级杂交稻育种三步法的技术路线,成功选育了父本996和两用核不育系C815S两个超级杂交稻亲本,利用前者选育出适合长江中下游稻区作双季早稻种植的超级杂交早稻组合陆两优996,用后者选配出C两优87和C两优396等增产幅度大、极有应用前景的超级稻新组合.遵循水稻光温敏不育系选育的技术路线,育成C815S,P88S和9771S等实用的水稻两用核不育系.     

鞘翅目昆虫性别决定的研究进展

鞘翅目为昆虫纲最大的一个目，许多种类是农业、林业、果树和园艺作物的重要害虫，研究和揭示鞘翅目昆虫发生的内在机制、种群繁衍和适应性进化等成为保护农林业生产和生态环境建设的重要任务。鞘翅目昆虫由于交配、产卵、取食和生活方法等生命活动的多样性、特异性，使得鞘翅目昆虫性别决定机制十分复杂、多样。对鞘翅目昆虫性别决定基因特性、重要性别决定相关基因的分子级联互作、性别决定基因在鞘翅目昆虫发育中的作用和机制，以及影响性别决定的因素进行综述，旨在为深入研究鞘翅目昆虫性别决定的调控、种群繁衍、数量动态和进化提供理论基础。     

AL型小麦育性恢复主基因+多基因混合遗传分析

[目的]研究 AL 型雄性不育育性恢复基因的遗传模型.[方法]通过 AL 型小麦不育系(♀)与恢复系(♂)杂交,获得杂交后代分离群体,采用植物数量性状主基因+多基因混合遗传模型分离分析法对亲本 P1 和 P2 以及杂种后代 Fl 和 F2 群体 4 个世代的育性进行分析.[结果]AL 型育性恢复基因的最适遗传模型为 E-1,育性恢复基因由两对加性-显性-上位性主基因和加性-显性多基因共同控制,主基因遗传率为 85.92;.[结论]小麦 AL 型雄性不育育性恢复基因由两对主效基因和多对微效基因控制,主效基因遗传力较高,在小麦育种中有较高的利用价值.