植物数量性状遗传体系的分离分析方法研究

在传统的数量性状多基因遗传模型基础上提出主基因-多基因遗传模型具普遍性,纯主基因或纯多基因遗传模型只是其特例。由此初步建立了植物数量性状遗传体系分离分析方法。目前该方法可以检验2～3个主基因的个别遗传效应、多基因整体的遗传效应和两者的遗传率。本文介绍这种分离分析方法的研究经过、主要进展及应用效果,并以实例说明其分析步骤、方法和效果。     

RFLP遗传标记与作物数量性状基因定位

在农作物中许多主要经济性状属由单个基因效应微小的多基因控制且易受环境影响的数量性状。多年来对这类性状的遗传研究主要采用数量遗传学方法,通过适当的试验设计和统计模型估算出乎均数、方差、协方差、遗传力、配 合力、遗传距离,基因加性效应显性效应上位性效应等遗传参数,用这些参数描述群体的遗传特征,对育种研究起到了一定的指导作用。     

数量性状主要基因随机效应的分析

数量性状主基因在不同环境或遗传背景中表现随机效应。本文提出数量性状基因随机效应分析的试验设计和统计模型,以及对基因的分离比、平均效应和随机方差进行假设测验的方法．所述方法可用于借助标记基因对数量性状基因效应作类似分析．     

甘蓝型油菜主要农艺性状的遗传模型和基因效应分析

本文以甘蓝型优质油菜(81008×Tower)正反交各12个世代的资料,按照4种不同的遗传模型,对包括单株产量在内的8个农艺性状的遗传方式进行了详尽地分析。结果表明:所有性状的遗传皆不符合简单的加性-显性模型,上位性效应普遍存在,且对世代平均数有较大影响;单株产量及几个产量性状的遗传均受重复型互作基因的控制,杂种优势需利用三基因或多基因间的互作效应。     

IGF-1基因对长白×蓝塘猪资源群生产性能的遗传效应分析

利用F2代设计建立了由216头F2代个体组成的长白×蓝塘猪资源群,应用PCR-RFLP方法检测F2代个体IGF-1基因的多态性;通过固定模型方法估计了IGF-1不同基因型的最小二乘均值,同时采用混合模型方法分析不同性状IGF-1基因型的遗传效应,并由此计算IGF-1基因的加性和显性效应.固定模型和混合模型方法的分析结果都表明,IGF-1不同基因型对猪断奶后日增重有显著影响,AA型的遗传效应显著比AB型高20.58 g(P=0.0347),IGF-1基因对该性状的加性和显性效应分别为1.78 g和-18.81 g;对胴体组成性状也有影响,AA型和AB型对骨率的遗传效应分别极显著低于BB型5.22%(P= 0.0008)和5.19%(P=0.0007),IGF-1基因对该性状的加性和显性效应分别为-2.61%和-2.58%;AA型胴体瘦肉量的遗传效应显著比AB型少0.45 kg(P=0.0264),IGF-1基因对该性状的加性和显效应分别为0.16 kg和0.61 kg;AA型和AB型皮脂率的遗传效应比BB型分别高8.81%(P=0.0206)和7.64%(P=0.0431),对该性状的加性和显性效应分别为4.41%和3.24%.因此,IGF-1基因的遗传效应分析说明该基因对断奶后日增重、骨率、胴体瘦肉量和皮脂率等4个性状有显著的遗传影响;而加性和显性效应估计值的大小表明,IGF-1基因的遗传效应只有在皮脂率性状上加性效应相对显性效应比较高,可以作为主基因对该性状进行有效选择.     

远交群体动态性状基因定位的似然分析Ⅰ.理论方法

受动物遗传育种中用来估计动态性状育种值的随机回归测定日模型思想的启发 ,将关于时间 (测定日期 )的Legendre多项式镶嵌在遗传模型的每个遗传效应中 ,以刻画QTL对动态性状变化过程的作用 ,从而建立起动态性状基因定位的数学模型。利用远交设计群体 ,阐述了动态性状基因定位的似然分析原理 ,推导了定位参数似然估计的EM法两步求解过程。结合动态性状遗传分析的特点和普通数量性状基因定位研究进展 ,还提出了有关动态性状基因定位进一步研究的设想     

稻米碾磨品质性状遗传主效应及其与环境互作的遗传分析

采用包括遗传主效应和基因型与环境互作效应的种子三倍体遗传模型,分析了不同环境条件下籼稻稻米碾磨品质的遗传特性。结果表明,各碾磨品质性状除了受制于种子基因效应、细胞质效应和母体植株基因效应等遗传主效应外,还会明显受到各遗传效应与环境互作效应的影响。其中精米重和精米率两个性状的表现主要是以遗传主效应为主,而糙米重和糙米率则以基因型ｘ环境互作效应为主。在各遗传体系中,除了精米率性状的种子直接遗传效应与环境的互作效应略大于母体植株遗传效应与环境的互作效应外,其他碾磨品质性状的母体植株基因的表达受环境条件的影响程度要大于种子基因。细胞质ｘ环境互作效应对精米重和糙米率的影响也较为重要。遗传效应预测值结果表明,Ｐ７和Ｐ８两个亲本的遗传主效应表现突出,可以明显改良杂交后代多数碾磨品质性状。Ｐ１和Ｐ２两个亲本的碾磨品质性状预测值在两年中的环境互作效应较为－致,不易受到外界条件的影响。上述亲本在水稻品质育种中可加以利用。     

黄瓜雄花性状的遗传分析

为了解黄瓜雄花花器的遗传特性,该研究以雄花器官较小的华南型黄瓜二早子为母本,花器较大的加工型黄瓜NC-76为父本,构建4世代遗传群体,并采用多世代联合分离分析方法,分析黄瓜雄花花器性状的遗传特性。结果表明:分离群体的雄花花梗和花冠长2个性状均表现为单峰分布,表明两性状为数量性状且有主基因控制;花梗长性状符合2对完全显性主基因+加性-显性多基因(E-5)模型,花冠长性状符合2对加性-显性-上位性主基因+加性-显性-上位性多基因(E-1)模型;控制花梗长性状的两对主基因的加性效应相等,为0.573,多基因的加性效应和显性效应值相差不大,且均为负向;控制花冠长度性状的2对主基因的加性效应均为0,显性效应分别为-0.226和-0.472,在上位性作用中以加性×加性和显性×显性互作为主,多基因以显性效应为主,正向显性效应值为0.613,大于负向的加性效应值。花梗和花冠长度两个性状在F2群体中主基因遗传率分别为61.04%和69.60%,多基因遗传率均为0。由此看出黄瓜雄花花器性状为数量遗传,遗传率相对较高。该研究结果显示在黄瓜杂交育种中对花器大小选择可以在较早世代选择。     

胚乳性状的遗传模型和世代平均数

谷类作物的胚乳是三倍体组织,胚乳性状受3N遗传控制。本文分析了胚乳性状的遗传特征,建立了相应的遗传模型,推导了世代群体的平均数分量,并提出了研究胚乳性状基因效应的一些简单的交配设计。     

远交群体动态性状基因定位的似然分析 I．理论方法

受动物遗传育种中用来估计动态性状育种值的随机回归测定日模型思想的启发,将关于时间(测定日期)的Legendre多项式镶嵌在遗传模型的每个遗传效应中,以刻画QTL对动态性状变化过程的作用,从而建立起动态性状基因定位的数学模型。利用远交设计群体,阐述了动态性状基因定位的似然分析原理,推导了定位参数似然估计的EM法两步求解过程。结合动态性状遗传分析的特点和普通数量性状基因定位研究进展,还提出了有关动态性状基因定位进一步研究的设想。     

糖皮质激素非基因组效应的研究

在过去的几十年间,人们认为糖皮质激素（glucocorticoid,GC）仅仅是通过改变基因的表达来发挥其生理作用,这个过程需要几个小时来完成。然而,近年来越来越多的证据表明GC对激素分泌、神经元兴奋性、机体行为及细胞形态、糖类代谢等具备快速效应,这些过程往往在数秒钟或者分种内完成,这种作用机制被称为GC的非基因组作用机制。GC的非基因组作用主要可能通过两种不同的机制起作用：（1）通过细胞膜上或者细胞质内结构未知的糖皮质激素受体（glucocorticoid Recptor,GR）来发挥非基因组作用,即为特异性非基因组效应,（2）GC主要通过改变细胞膜理化作用来发挥效应。也称为非特异性非基因组效应（non-specific nongenomic effects,NSNE）。本文通过阐述近年来GC的非基因组的作用的最新研究进展并且讨论了这些非基因组作用临床治疗过程中的联系。对糖皮质激素基因组和非基因组作用机制的深入了解有助于指导我们在临床合理用药并减少其副作用。     

普通玉米籽粒性状的遗传效应分析

采用二倍体种子遗传模型及其分析方法,研究了５个玉米籽粒性状的直接效应、母体效应和细胞质效应．分析结果表明,各性状的遗传同时受种子直接效应和母体效应的影响,细胞质基因对百粒重和粒宽具有极显著影响．除粒长、粒厚的直接显性效应与母体显性效应间的协方差外,直接效应与母体效应间的协方差均不显著．因此,通过母体植株的表现可对这些性状进行有效的选择．Ｓ_２２和 ８７－１是改良粒重的优良亲本．选择粒较宽的自交系作母本有利于提高后代选系及Ｆ_１的百粒重．     

Across species‐pool aggregation alters grassland productivity and diversity

Plant performance is determined by the balance of intra‐ and interspecific neighbors within an individual's zone of influence. If individuals interact over smaller scales than the scales at which communities are measured, then altering neighborhood interactions may fundamentally affect community responses. These interactions can be altered by changing the number (species richness), abundances (species evenness), and positions (species pattern) of the resident plant species, and we aimed to test whether aggregating species at planting would alter effects of species richness and evenness on biomass production at a common scale of observation in grasslands. We varied plant species richness (2, 4, or 8 species and monocultures), evenness (0.64, 0.8, or 1.0), and pattern (planted randomly or aggregated in groups of four individuals) within 1 × 1 m plots established with transplants from a pool of 16 tallgrass prairie species and assessed plot‐scale biomass production and diversity over the first three growing seasons. As expected, more species‐rich plots produced more biomass by the end of the third growing season, an effect associated with a shift from selection to complementarity effects over time. Aggregating conspecifics at a 0.25‐m scale marginally reduced biomass production across all treatments and increased diversity in the most even plots, but did not alter biodiversity effects or richness–productivity relationships. Results support the hypothesis that fine‐scale species aggregation affects diversity by promoting species coexistence in this system. However, results indicate that inherent changes in species neighborhood relationships along grassland diversity gradients may only minimally affect community (meter) – scale responses among similarly designed biodiversity–ecosystem function studies. Given that species varied in their responses to local aggregation, it may be possible to use such species‐specific results to spatially design larger‐scale grassland communities to achieve desired diversity and productivity responses.     

Bacterial survival in evaporating deposited droplets on a teflon-coated surface

Understanding of bacterial survival in aerosols is crucial for controlling infection transmission via airborne aerosols and/or large droplets routes. The cell viability changes of four bacteria species (Escherichia coli K12 JM109; Acinetobacter sp. 5A5; Pseudomonas oleovorans X5; and Staphylococcus aureus X8), three Gram-negative and one Gram-positive, in a large evaporating droplet of size 1,800 μm in diameter on teflon-coated slides were measured using the LIVE/DEAD BacLight solution and a microscope. Droplets of three levels of salinity (0, 0.9, and 36% w/v) were tested. All four species survived well during the droplet evaporation process, but died mostly at the time when droplets were dried out at 40–45 min. The final bacteria survival rate after droplets were completely dried was dependent on bacteria species and the salinity of the suspension solution. Droplet evaporation over the first 35–40 min had no adverse effect on bacterial survival for the droplets tested. The lethal effect of desiccation was found to be the most important death mechanism.     

片断森林植物多样性及其保护和恢复价值

森林片断化是导致生物多样性丧失最严重的单一因素。在片断森林中植物多样性除与片断面积有关外,还受边缘效应、瞬时取样效应、驰豫效应、远距离扩散的挽救效应以及背景生态系统的性质等影响。本文阐述了在这些综合因素影响下,片断森林中植物种类、丰富、性质的变化。由于这些综合因素的影响,不少片断森林尚有较高的保护价值,但需建立合适的评价体系和标准。片断森林在确定生态恢复目标、为恢复实践提供种源等方面也有重要价值。提出了对片断森林的保护措施。     

大坝的生态效应:概念、研究热点及展望

大坝产生的生态效应涉及范围广、周期长,在对社会经济发展起到积极作用的同时,也对生态、环境造成了一定的影响。在评述国内外对大坝生态效应概念和内涵理解的基础上,提出了大坝生态效应链和生态效应网的概念。依据大坝建设和运行的特点,结合流域生态系统的特征分别论述了大坝对水文、局地生态的调节效应以及屏障效应和岛屿化、截留效应、边缘效应、水温效应等国内外研究的热点。最后,提出了今后大坝生态效应的研究方向:1)生态正效应、生态效应链和生态效应网;2)生态系统过程和状态生态效应;3)不同时空尺度下生态效应及其尺度推绎方法等3个方面的研究。     

压力波对听觉器官的致伤作用——Ⅱ.压力波参数与伤情的关系

压力峰值 P、脉宽 T 和发数 N 是决定压力波致伤作用的基本参量,它们之一的增大一般都导致伤情的加重,但中耳损伤和内耳损伤各有不同的变化规律。当 N 为1、T 在几毫秒之内时,170dB 左右的 P 可以开始对豚鼠的中耳致伤,P 增至185dB 左右时中耳损伤便达到最大。T 和 N 的增大虽也可稍降低中耳的致伤阈或使损伤稍加重,但其主要作用则是加重内耳的伤情。若将听觉器官的损伤从最轻到最重分成5级,则每当 P 增高3—4dB,或 T 或 N 增3—5倍,伤情大体上加重一级。因此若 T 和 N 不变,压力峰值超出安全界线15dB 便可能引起严重的听觉损伤。在数秒到数十分钟的范围内,发射的间隔时间对伤情的影响不大。但当发射的间隔时间缩短到<1s(如100ms)时,对一定发数的总伤情便可稍减轻,此结果可用中耳反射的保护作用来解释。     

Stomach cancer incidence trends in selected Latin America countries: Age,period, and birth-cohort effects

Backgroundto explore the age, period, and birth-cohort effects on stomach cancer incidence trends during 3 decades in selected Latin American countries.Methodsa time-trend study was performed using Cancer Incidence in Five Continents data from high-quality population-based cancer registries(PBCRs) in Latin American countries. Crude and age-standardized incidence rates(ASRIs) were calculated. Time trends in ASRIs were assessed using the average annual percentage change(AAPC). Age-period-cohort effects were estimated by Poisson regression for individuals aged between 20 and 79 years with stomach cancer informed by PBCRs from 1983 to 2012 in Cali(Colombia); from 1982 to 2011 in Costa Rica; and from 1988 to 2012 for Goiania(Brazil) and Quito(Ecuador). The goodness-of-fit model was tested using the deviance of the models.Resultsa decrease in age-standardized incidence rates was observed for both genders in all populations covered by PBCRs, except for young men from Cali(AAPC 3.89 95 %IC: 1.32–7.29). The age effect was statistically significant in all areas, and the curve slope reached peaks in the older age groups. The cohort effect was observed in all PBCRs. Regarding the period effect, an increased ratio rate was observed for both genders in Costa Rica(1997–2001 women RR 1.11 95 %CI: 1.05–1.17; men RR 1.12 95 %CI: 1.08–1.17) and Goiânia(2003–2007 women RR 1.21 95 %CI: 1.08–1.35; men RR 1.09 95 %CI: 1.01–1.20), while Quito(1998–2002 women RR 0.89 95 %CI: 0.81–0.98; men RR 0.86 95 %CI: 0.79–0.93) presented a decrease.Conclusionthe present study showed a decreasing gastric cancer trend for over the past 30 years with gender and geographic variations. Such a decrease seems to be mainly a result of cohort effects, suggesting that the economic market opening process led to changes in the risk factor exposures over successive generations. These geographic and gender variations may reflect cultural/ethnic/gender differences and differences in dietary and smoking rate patterns. However, an increased incidence was observed for young men in Cali, and additional studies are needed to determine the cause of the increasing incidence in this group.     

Anti-inflammatory,anti-oxidant effect and cytotoxicity of ocimum sanctum intra oral gel for combating periodontal diseases

It is of interest to evaluate the anti-inflammatory, anti-oxidant effect and cytotoxicity of Ocimum sanctum (an Indian herb, Thulsi) intra oral gel in combating periodontal diseases. Hence, 2% of O. sanctum gel was prepared with Carbopol940 soaked in purified water containing 0.2% w/v sodium benzoate overnight. Hydroxy proplyl methyl cellulose (HPMC) solution was mixed with propylene glycol using using tissue homogenizer. Anti-oxidant effect was analyzed using DPPH radical assay and anti-inflammatory effect was assessed using the inhibition of albumin denaturation assay. Ocimum sanctum gel with various dilutions from10 micro litres to 50 micro litres showed exponential increase in percentage of inhibition from 60.9 to 72.2 exhibiting antioxidant activity. The anti-inflammatory effect of Ocimum sanctum gel showed comparatively equivalent effect with standard diclofenac gel with values ranging from 76.6 for 50 micro liters of Ocimum sanctum gel and 89.6 for standard gel at 50 micro liters. Ocimum sanctum showed less toxicity towards brine shrimp nauplii. Thus we show that Ocimum sanctum gel showed potent anti-oxidant and anti-inflammatory effect and less toxic to brine shrimp nauplii as a promising agent for the treatment of periodontal diseases.     

栖息地破碎化与鸟类生存

栖息地破碎化给野生动物带来的不良后果是全球生态学家和保护生物学家共同关心的问题.自从提出栖息地破碎化是导致生物多样性丧失的关键因素之一的论点后,近20年来,栖息地破碎化研究一直是生态学和保护生物学最活跃的前沿研究领域之一.栖息地破碎化是一动态过程,可在多尺度上发生并蕴涵着复杂的空间模式变化.栖息地破碎化对鸟类的生态学效应主要体现在面积效应、隔离效应和边缘效应等.这些效应影响着鸟类的分布、基因交流、种群动态、扩散行为、种间关系和生活史特征等,最终影响着鸟类的生存.介绍和总结了栖息地破碎化过程、研究的理论依据及栖息地破碎化对鸟类生存产生的诸多影响.