基于氨基酸分类的基本氨基酸秩序的研究

在分析了基本氛基酸分类的基础上,提出基本氛基酸存在着一种参考排列秩序,以此固定的氛基酸排列秩序为参考标准,分析蛋白质一级结构相对此参考秩序的变化规律,能够找到构成蛋白质的二级结构的某些信息．     

图论方法研究蛋白质结构预测问题

图论方法在蛋白质结构预测中占有重要地位。该文简要介绍图的连通子图、图的最大团、图的完美匹配及图谱法在蛋白质结构预测中的应用。对国内外近年来应用这些方法在蛋白质3D结构预测及折叠的研究工作进行了回顾,并分析、比较了这几种方法的效果和特点。     

小麦异交群体连续歧化选择的RAPD分析

利用太谷核不育基因构建的遗传变异丰富的基础群体DNS2,进行了连续5轮歧化选择。本论文从不同的世代中,选择了10个子群体进行RAPD分析。采用7个引物扩增出116个位点,从基因频率和表型带两个角度的分析都表明,群体具有丰富的遗传变异。整个群体总的多态位点百分率达88.79,总杂合度为0.3143。子群体内（间）遗传距离的结果显示：子群体内的遗传差异小于子群体间的遗传差异;各选择子群体与未选群体间都有较大的遗传距离;随着选择轮次的增加,株高选择子群体间的遗传距离逐渐增大;对同一性状进行选择的子群体间世代内（间）平均遗传距离小于对不同性状进行选择的子群体内（间）的遗传距离。RAPD分子聚类结果显示出对同一性状进行选择的子群体聚在一起,反映了对株高选高的选择效果比较明显。 Abstract:A base population was established through multi-parent random crossing by using Taigu dominant male-sterile wheat,and then five cycles of 2-way selection for four quantitative characters were conducted.The dynamic changes of genetic structures in the open-pollinated wheat population were examined by RAPD technique.Seven primers in RAPD analysis amplified 116 sites.The results of gene frequencies and phenotypic bands showed abundant genetic variations existed in the population.The percentage of polymorphic loci was 8879,and the average heterozygosity was 0.3143 in the whole population.The genetic distance of RAPD showed as follows :① The genetic distance within a subpopulation was lower than that between every two subpopulations.② Each subpopulation had considerable divergence compared with unselected population.③ The genetic distances between the subpopulations which were selected for plant height gradually increased accompanied with the selection.④The genetic distance between subpopulations which were selected for the same character was lower than that were selected for different characters both in the same generation and among different generations.The cluster results of RAPD genetic distance demonstrated that the subpopulations selected for the same character going to one cluster.It also showed that the selective effect of increasing plant height was obvious.     

UCP2启动子-866G/A与APOEε 4多态性在糖尿病肾病发生中的协同效应

目的:探讨解耦联蛋白2基因(UCP2)启动子变异-866G/A及载脂蛋白E与北京人群糖尿病肾病(DN)的发生关联和协同效应.方法:基于聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)技术,对228例DN患者,243例非DN的2型糖尿病患者及78例正常对照进行基因分型,同时进行体格检查和生化指标测定,数据处理使用SPSS(version16.0)完成,用Hardy-Weinberg平衡检验评价人群代表性,按照加性模型分析基因型的整体分布规律,隐性模型和显性模型分析风险等位基因与疾病的关联,通过Logistic回归分析基因变异间的交互作用,分层分析评估其相互作用对DN的贡献.结果:加性模型分析提示UCP2基因-866G/A在DN组和DM组间的分布差异达到统计学显著性(P＜0.001),进一步通过显性模型发现-866A同DN存在正关联,调整年龄和性别混杂后,正关联仍然存在(OR=1.814,95％CI:1.148-2.867).UCP2×APOE交互项和DN存在独立于年龄、性别、体质指数、血糖、甘油三酯等血脂指标的正关联,二者存在效应的协同作用.分层分析表明UCP2基因-866A是独立APOEε4的DN的危险因素,且APOEε4对UCP2基因-866A存在异位显性(epistasis)关系.结论:UCP2基因启动子-866A等位基因和APOEε4等位基因是北京汉族人群DN的风险等位基因,APOEε4存在异位显性,二者效应存在叠加.