遗传型的

Since Watson and Crick have brought forward the model of DNA helix structure and explain about it's reproduce mechanism in molecule level, research work concerning DNA has been continuously lucubrated. However, whether translating inheritance information and rebuilding DNA molecule via menstruating DNA sequence, or to date the most compelling gene project, chromosome protract et. al, there all need a sort of molecule scissors cleaving DNA, DNA cleavage reagent. At present, tool enzyme of cleaving DNA is mostly DNA restriction enzymes founded in 70 years, which only cleave DNA at specific 4-8 base pair sequences that are usually palindromic, so this restricts the at very fast speed developing of gene technology at certain extent.

自从Watson和Crick提出DNA的双螺旋结构并对其复制机制在分子水平上进行解释后，使得对DNA的研究不断深入，但无论是通过测定DNA的序列来破译遗传信息、改造DNA分子，还是目前最令人关注的基因工程、染色体绘制等，都需要一种断裂DNA分子的&剪刀&——DNA断裂试剂，目前断裂DNA的工具酶主要是上个世纪70年代发现的DNA限制性内切酶，但所知的Ⅱ型限制性内切酶的DNA序列识别长度较短（约为4～8个碱基对），而且一般要求回文结构，这就给飞速发展的基因工程技术带来一定的限制。

In this study, genetic analyses were conducted to determine the genetic basis in an elite resistant inbred line Siyi with complete resistance to maize dwarf mosaic. A new genetic model, two dominant complementary genes conditioning the resistance, were found by Mendelian genetic analysis based on parents, F1, F2 and backcrosses in three successive years' field trails. The two genes were further mapped near the centromere of chromosome 3 and 6, respectively by tightly linked microsatellite markers using 242 plants from F2 generation. The resistance gene on chromosome 3 is 1.0 cM apart from the flanking markers phi053 and umc1527, respectively. Whereas the linkage distance between two flanking markers bnlg1600 and phi075 and resistance gene on chromosome 6 was 1.0 and 4.0 cM, respectively. Genotypic analysis of the plants from testcross and F3 populations supported the new genetic manners.

课题组通过连续三年的抗病鉴定，在国内种质资源中筛选出一份综合农艺性状优良、配合力较高的自交系四一，三年的表型遗传研究和两年的分子标记工作，发现四一中的玉米矮花叶病抗性是由两对显性互补基因控制的，进而利用F2作图群体，把发现的两个基因定位在第三和第六染色体的着丝点附近，并获得了双侧紧密连锁的分子标记连锁图谱，其中第三染色体上的分子标记UMC1527和phi053从抗病基因双侧逼近1 cM，而第六染色体上的分子标记phi075、bnlg1600从抗病基因双侧分别逼近4 cM和1 cM；利用B2群体、F2：3家系、BC3F1群体和带有第三、第六染色体抗病基因以及两个抗病基因的近等基因系，进一步证实了四一中成株期抗性是由两个显性互补基因控制的。

The concept of equivalent rotationally rigidity is offered and the formula of rotationally rigidity is obtained.

主要做了如下几个方面的工作：对伸臂位于顶部的单层框架—筒体模型进行分析，提出了等效转动约束的概念和转动约束刚度的表达式。

Male cats normally do not need aftercare with the exception of the night after the anesthetic.

男猫通常不需要善后除了晚上的麻醉。