Four kinds of ENU-induced white spot mice and chromosome locations of the mutant genes

After the accomplishment of the Human Genome Project, life sciences have entered a post-genome era to systematically study gene functions on a large scale[1]. Because of its similarity to humanity in genomic se-quences, biochemical metabolism and physiological mechanism, Mus musculus is the ideal model animal in the study of functional genome. As the publication of the draft map of mouse genome sequences in December 2002, studying gene functions by mouse enters a new stage[2]. So far, there …     

Characterization and mapping of a white panicle mutant gene in rice

A spontaneous white panicle mutant was found from the F6 progenies of an indicajaponica cross.The mutant exhibits white stripes on its basal leaves while the panicles,rachis and pedicel are milky white colored at flowering stage.Genetic analysis in an F2 population from the cross of Zhi7/white panicle mutant indicates that the white panicle phenotype is controlled by a single recessive nuclear gene,tentatively termed as wp(t).Using microsatellite markers,the wp(t) gene was anchored between the markers of SSR101 and SSR63.9 with a map distance of 2.3 and 0.8cM,respectively,and co-segregated with the marker of SSR17 on rice chromosome 1.     

动载滑动轴承优化设计研究

作者建立了以降低动耗为目标的动载滑动轴承优化设计数学模型,使用随机方向搜索法、复合形法、混合罚函数法编制了通用优化设计程序,并针对通用优化方法的弱点,提出三个改进措施:采用“灵敏度加权法”确定合理搜索方向,按约束值大小确定合理搜索步长,应用随机方向搜索法为复合形法产生合理的初始复合形。算例证明,本数学模及改进措施是合理的,其基本原理可用于机械优化设计的其他领域。     

山羊和藏羚羊全基因组微卫星分布规律及其生物信息学分析

本文利用生物信息学方法搜索和统计了山羊和藏羚羊全基因组中完整型SSRs序列,并对其生物信息学特征进行比较分析.山羊和藏羚羊全基因组中SSRs总数量分别为920 300个和913 059个,占其全基因组长度的比例分别为5.56‰和5.39‰.山羊和藏羚羊全基因组SSRs六种重复类型的数量、比例、丰度和密度分布模式如下:单核苷酸SSRs二核苷酸SSRs三核苷酸SSRs五核苷酸SSRs四核苷酸SSRs六核苷酸SSRs,这六种重复类型SSRs特征相互比较有显著差异,而相同重复类型SSRs特征基本一致.山羊基因5′端非翻译区和外显子区均是三核苷酸SSR丰最丰富,其次依次是单核苷酸、二核苷酸、四核苷酸、五核苷酸和六核苷酸;而其3′端非翻译区和内含子区均是单核苷酸SSR最丰富,其次依次是二核苷酸、四核苷酸、三核苷酸、五核苷酸和六核苷酸.山羊第1条染色体上SSRs数量最多,其次依次是第2条、X染色体、第6条、第4条和第8条染色体,而较少的是第25、28条染色体,所有染色体上SSRs丰度不存在显著差异.山羊和藏羚羊全基因组各重复类型优势SSRs序列基本一致,并与牛、绵羊全基因组中不同重复类型SSRs优势序列相一致.     

微卫星DNA技术及其应用的探讨

微卫星DNA是一类短串联重复的寡核苷酸，广泛的分散于整个基因组中，具有多态性高、突变速率快等特点，在医学领域、生物学领域应用广泛。本文综述了微卫星多态性形成机制、序列获得方法及其应用途径，尤其是微卫星不稳定性与疾病的相互关系。     

江西汉族人群13个STR基因座的遗传多态性研究

采用荧光标记复合扩增的方法对江西汉族人群D3S1358、vWA、FGA、D8S1179、D21S11、D18S51、D5S818、D13S317、D7S820、D16S539、THO1，TPOX、CSF1PO等13个STR基因座的基因频率调查，获得了江西人群13个STR基因座的基础数据，结果表明，D3S1358等13个STR基因座是一组高多态性的遗传标记系统，在法医学及人类遗传学研究应用中具有重要意义。     

Conditional and unconditional mapping of quantitative trait loci underlying plant height and tiller number in rice (Oryza sativa L.)grown at two nitrogen levels

In this study, we used 127 double haploid (DH) lines to analyze agricultural traits of rice. The DH lines, derived from a ZYQ8 (indica)/JX17 (japonica) cross by anther culture, contained 160 RFLP and 83 SSR markers. Unconditional and conditional quantitative trait loci (QTL) mapping was conducted to analyze plant height (PH) and tillers per plant (TP) at ?ve growth stages that were grown at two nitrogen levels. Fourteen PH and 13 TP unconditional QTL were identified in the di?erent growth stages, including 19 QTL from high-nitrogen (HN) and 14 QTL from low-nitrogen (LN) conditions. The conditional QTL for 14 genomic regions under LN/HN conditions showed that there was a significant effect on PH and TP across the different stages. Only one conditional QTL, ph2-3, was unable to be detected in unconditional mapping. More QTL were detected in the ?rst four rice growth stages than in the final stage. Furthermore, a line from the DH mapping population, DH78, was identified in extreme phenotypes of PH and TP that exhibited dwarfism and less-tiller (dft) characters. The gene dft1 was mapped to chromosome 2 using a backcrossed population of DH78/JX17 through a mapbased cloning strategy. The location of dft1 coincided with the mapping region of the small-LOD peak, QTL ph2 and tp2, which were identified in plants grown in low-nitrogen conditions. Further backcrossing and fine-mapping successfully delimited the dft1 locus to a 91 kb region.     

异源多倍化引起的小麦微卫星序列变异

利用80对小麦微卫星引物调查了小麦黑麦双二倍体形成过程中微卫星序列的变异情况.结果显示: 8对引物能从杂交F1植株及亲本小麦植株的基因组中扩增出相同的带型,而在新合成的双二倍体中条带缺失;4对引物从杂交F1植株及亲本小麦植株的基因组中扩增出相同的带型,而在新合成的双二倍体中扩增的条带变短;其余引物从亲本小麦、F1植株及双二倍体中扩增的带型相同.将有长度变化的条带回收测序,发现双二倍体中的条带变短现象是由二核苷酸重复单位减少所致.这些结果表明:常发生在二倍体生物中的微卫星序列变异现象在植物异源多倍化过程中也会发生,异源多倍化可能是促进微卫星进化的又一个不可忽视的动力.和二倍体生物一样,异源多倍化诱导的微卫星序列进化也表现为长的重复序列趋向缩短.     

动态复杂性状遗传结构研究的统计模型

许多重要的农艺性状、生物学和生物医学性状都是数量性状,这些性状在不同的发育阶段发生变化,并表现出复杂的动态特征。针对这些动态性状,传统的遗传作图方法是通过在不同的年龄或发育阶段利用遗传标记与表型性状进行关联分析,并比较这些性状在不同发育阶段的差异,或者通过进行不同阶段的多位点作图进行分析。然而,这些方法并不能确切地反映整个发育过程和动态特点,这使得对性状遗传结构的推测受到限制。要克服这一困难,函数作图将为动态性状的遗传学研究提供一条有效的途径。函数作图综合了生物学机制的数学特性和性状遗传作图的统计学特点,结合统计模型、遗传学和发育生物学的函数作图策略,力求解决诸如发育的遗传控制模式、QTL的持续效应以及引起发育过程中启动和终止的遗传机制等问题。笔者提出的函数作图策略将提供一个研究基因作用及互作与发育模式之间有效的量化检测平台。     

不结球白菜SSR引物的高效开发及其通用性研究

利用改进的ISSR-PCR分离不结球白菜基因组微卫星,进行两步PCR,分别设计出SSR两端引物IP2和IP3（即SSR引物对）,SSR引物产率为12%,明显高于传统方法.不结球白菜SSR序列以（GA）n为主,占70%.将69对SSR引物用于芸苔属其它8种作物的扩增,97%引物有显著扩增,扩增率最高的为四倍体白菜和甘蓝（85.5%）,最低的为青花菜（49.3%）.10对为通用引物,在所检测的8种作物中片段大小一致,其余的扩增片段和数目差异较大,表现出较为丰富的多态性.尤其是在C基因组的甘蓝和花椰菜上,最多可检测到5个位点,表明运用lSSR-PCR开发出的引物多态性较高.