论受控于X连锁基因性状的变异性

本文应用数量遗传学方法,结合概率运算,从理论上分析了由X连锁基因控制的性状在雌雄群体中的变异情况。表明雄（男）性群体的这类性状遗传变异范围有大于雌（女）性群体的倾向。对这一问题的探讨,将有助于对X连锁基因及所决定性状的遗传特性、进化特点及基因定位等的研究提供新的思路。     

家蚕内网虫属微孢虫核糖体小亚单位RNA(SSUrRNA)核心序列的克隆和序列分析

Endoreticulatus bombycis is a new pathogenic microspordia isolated from the silkworm larvae.With polymerase chain reaction(PCR) method,we amplified a fragment of the core sequence of the small subunit ribosomal RNA( SSUr-RNA) of Endoreticulatus bombycis.The SSUrRNA fragment was inserted into pMD18-T Vector and then cloned.It had a length of 1230 nucleotides and a percentage GC content of 51.3%.The accession number in Genbank is gill 181769|AY009115.The secondary structure model of the SSUrRNA of Endoreticulatus bombycis was constructed both on the bases of the sequence alignment and RNAFOLD program of the PC-GENE package.The secondary structure model revealed that Endoreticulatus bombycis lacked many cukaryotic hclices.such as heli10,helix 11.helix 18,helix 43 and helix 46,but it has V4 region and has more of prokaryotic character.Analyzed by Blast,Endoreticulatus bombycis.Endoreticulatus schubergi and pleistophora sp.(Sd-Nu-IW8201) have a high similarity,over 98%,Phylogeny tree of Endoreticulatus and Pleistophora species showed that Endoreticulatus and Pleistophora sp.(Sd0Nu-IW8201) was in a group and the other Pleistophora species were in another group[Acta Zoologica Sinica 49(3):414-420,2001].     

一个新的家蚕油蚕白卵系BH863的基因型研究

家蚕卵色正常型为黑褐色,其突变种类丰富,其中白色卵系列不失为一特色。迄今研究报道的家蚕白卵突变基因有１２种之多（向仲怀,１９９４;江口正治等,１９８６;Ｆｕｊｉｉ,１９９８;Ｃｈｉｓｈｕｓｈｉ,１９７２;Ｋｉｎｇ,１９７６）。本研究室发现１９９４年由广东省农科院蚕业所移送西南农业大学家蚕基因库保存和鉴定的ＢＨ８６３系是一种新的油蚕白卵突变。ＢＨ８６３系是以家蚕品种湖２０４（♀）为受体,蓖麻蚕品种斑马（♂）为供体,经人工授精产生的子代中的家蚕变异品系（陈元霖等,１９９３）。其主要性状特征为：浆液膜…     

一种简单、经济的植物RNA抽提方法

一种简单、经济的植物ＲＮＡ抽提方法孟玲谭德勇王焕效吕朝晖王晓燕周翔（云南大学生物系,昆明６５００９１）ＡＳｉｍｐｌｅＥｃｏｎｏｍｉｃａｌＭｅｔｈｏｄｆｏｒｔｈｅＩｓｏｌａｔｉｏｎｏｆＰｌａｎｔＲＮＡＭＥＮＧＬｉｎｇＴＡＮＤｅｙｏｎｇＷＡＮＧＨｕａｎｘ...     

家蚕近交系遗传纯度的RAPD检测

目的分析家蚕近交系IS-c108A的遗传纯度,为家蚕实验动物化的培育工作提供指导。方法应用经过筛选的20条随机引物对家蚕近交系IS-c108A(F10)的3个蛾区各30个个体和该近交系的亲本系统c108、对照实用化品种871各30个个体的基因组DNA进行RAPD扩增,计算个体间和蛾区间的相似系数及遗传距离。结果家蚕近交系IS-c108A(F10)的3个蛾区内的多态性带频率分别为1.807%、1.841%、1.841%,平均为1.830%;起点亲本c108个体间多态性带频率为7.207%,对照品种871个体间的多态性带频率为7.08%;而近交系IS-c108A与c108之间的多态性带频率为49.20%,c108和871品种之间的多态性带频率为58.33%。家蚕近交系IS-c108A10的3个蛾区内个体之间遗传相似系数的平均值分别为0.99581、0.99555、0.99551,总平均为0.99562。结论家蚕近交系IS-c108A(F10)已具有较高的遗传纯合度,家蚕具有易于获得高纯的有利条件。     

偏分离分子标记的作图方法

对取自MAPMAKER软件小鼠F2群体(含333个体)的5个RFLP连锁标记数据作了共显性分子标记偏分离的分析。先确定选择类型的方程组(配子或合子),随后采用Newton-Raphson迭代法估算标记间的重组值。在构建分子标记遗传图谱时,如果两个相邻标记均存在偏分离,最好采用纳入偏分离因子的估算方法。在估计F2群体标记间偏分离重组距离上,用连续χ2检测方法比传统χ2检测更为准确。Abstract The comparative analysis of segregation distortions of the codominant markers data presented in software MAPMAKER are made, where five RFLPs markers involve in a mouse F2 population with 333 individuals. The successive χ2 test begins with the determinations of gametic or zygotic selection types, followed by the estimation of recombination fractions between two markers with the Newton-Raphson iteration method. It is better to use the molecular marker showing segregation distortion for constructing a genetic map, in the case of seriously skew segregation between both the adjoining markers. The successive χ2 test provides better accuracy than that of classical χ2 test for the estimation of the recombination values in F2 population with segregation distortion.     

秦岭川金丝猴的一次家庭雄性替代

家庭雄性替代已在亚洲叶猴的许多种类中有所报道。 2 0 0 3年 ,我们在一种亚洲叶猴———秦岭的川金丝猴 (Rhinopithecusroxellana)的一个单雄家庭中观察到一次完整的家庭雄性替代过程。此次替代发生于 4月 2 8日 - 5月 2日的五天时间内。在家庭雄性发生替代后的第六个月 ,该家庭中的婴猴消失。本文是首次对野生川金丝猴家庭雄性替代进行详细的报道。通过本次观察证明野生川金丝猴的确存在家庭雄性替代的现象。且像亚洲叶猴的许多种类一样 ,野生川金丝猴的家庭雄性替代同样发生于产仔季节和交配季节之间。但我们仍无法确定在本次雄性替代中婴猴最终的消失是否是雄性杀婴的结果     

家蚕线粒体ND2、COⅠ和若干tRNA基因的克隆及序列分析

克隆并测定了家蚕（Bombyx mori）线粒体基因组3468bp的EcoRⅠ和HindⅢ双酶一段序列,根据序列同源性比较,该DNA片段包括3个蛋白质编码基因：ND2基因、COⅠ基因和COⅡ基因5′端399bp的序列,以及6个tRNA基因和一个尚待确定的tRNA^Met基因。家蚕与果蝇的ND2基因序列同源性约69.7%,COⅠ基因的同源性约83.8%,COⅡ基因5′端的同源性约80％,这表明细胞色素氧化酶基因在物种间比烟酰胺腺漂呤二核苷酸脱氢酶基因保守,6个推定的tRNA基因序列与果蝇相应tRNA基因序列差异较大,另外,除tRNA^Chn基因的二级结构相似外,其它tRNA基因的二级结构与果蝇相应tRNA基因的二级结构也有较大差异。     

家蚕分子连锁图谱的构建及分子标记育种研究进展

国际蚕分子育种计划(International Silkworm Project)是Rhode Island大学的M.R.Goldsmith在1991年提出来的,也叫基因标记育种计划[1].该计划主要包括两步工作:第一步是制作蚕的分子基因图, 第二步是数量性状定位分析(简称QTL分析,也叫数量性状定位作图:QTL Mapping).最后利用分子标记直接在DNA水平进行重要经济性状(数量性状)的选择、固定,即实施"分子育种",用很短时间育成兼具高抗、强健、丝多、质优、易繁等特性的新蚕品种,本文对此进行简要介绍.     

利用肠道菌群的分布和16S DNA序列研究鲤科肠道菌系统演化关系

肠道微生物与寄主具有复杂的、多方面的相互依存效应,这种依存效应所产生的共生关系或协同进化关系既可反映寄主间的系统演化关系,也可显示肠道微生物间的系统演化关系,共生关系或协同进化关系是由于寄主与肠道微生物两者之间存在着相互自然选择作用所形成的,在长期的进化历程中逐步发生的共生关系信息很可能被记录在DNA序列中。本文通过检测鲤鱼科8种鱼中9种肠道菌群的分布含量对这9种菌群进行分析,且利用从GenBank调取这9种肠道细菌菌属的43个种或亚种的16S DNA序列的构建NJ树和MP树,将这6个科9个属43个种或亚种分为革兰氏阴性和革兰氏阳性两大类群（一级分枝）。在这两类群中,又以科为单位分为6个亚类群（二级分枝）,而肠杆菌科中则以属为单位分为4个小类群（三级分枝）,此外球状菌与杆状菌也能截然分开。将16S DNA的NJ树隐去所有的种,以属为单位所得到的以分枝形式的无根树在拓扑结构上与菌群分布含量（寄主范围）所构建的无根树相近,但芽孢杆菌在两种无根树的位置中有较大的差异。如果提高检测水平,扩大所检测的寄主对象,这种差异有可能消除。 Abstract:There is a complex- and multi-effect for interdependent survival between intestinal- microorganisms and hosts.The symbiosis or coevolution that results from this effect for interdependent survival is used to reveal the phylogenies of hosts as well as intestinal microorganisms.The symbiosis or coevolution between intestinal microorganisms and hosts has been generated by interactive natural selection occurred between them.The symbiosis information that has been formed by interactive natural selection during a long evolutionary process must be recorded in DNA sequences.According to this point of view,we analyzed the phylogeny of 9 intestinal bacteria genera using their contents in intestines of 8 Cyrinidate species.At the same time,we fetched the 16S rRNA gene DNA sequences of 43 intestinal bacteria species being included in these nine genera of six intestinal families from GeneBank and constructed phylogenetic trees by NJ and MP methods.The NJ tree and MP tree have the same topologic configuration and are identical with the classical phylogenetic tree.Both the trees of 16S rRNA gene separated 43 bacteria species into gram-negative bacteria group and the gram-positive bacteria group,which are the first branches.Each of the first branches (groups) made again 6 subbranches (subgroups) where each subbranch is a family.Especially,the subbranch (subgroup) of enterobacteriaceace made again four small branches as genus taxon.This tree also shows that bacilliform bacterium is distinct from each other in the NJ and MP trees.After all species on the tree are merged,the topological configuration of the unrooted tree of 16S gene is closed to that of the host range unrooted tree.However,the position of bacillus is greatly changed on both the unrooted trees.The difference can be found if we increase the examination level and extend the hosts examed.