【作者】 郭万里；

【导师】 刘宝；

【作者基本信息】 东北师范大学 ， 植物学， 2006， 博士

【摘要】 本文首次采用分子标记技术AFLP(Amplified fragment length polymorphism)、S-SAP (Sequence-specific amplified polymorphism)和MSAP (Methylation-sensitive amplified polymorphism)三种分子标记研究了松嫩平原9个短芒野大麦((Hordeum brevisubulatum (Trin.) Link.))天然种群235个单株的分子遗传和表观遗传多样性及遗传结构分化,并对这三种分子标记进行了比较。采用AFLP和S-SAP分子标记对松嫩平原9个短芒野大麦天然种群遗传多样性和遗传结构进行了分析。两种标记的各种遗传多样性指标、基因流、遗传距离、聚类分析、PCA分析和AMOVA分析都表明,松嫩平原9个短芒野大麦天然种群遗传多样性和遗传结构变化的趋势是一致的。松嫩平原黑龙江省齐齐哈尔地区草原分布广泛,基本没有明显的人为干扰和山脉等地理隔离,并且适合短芒野大麦生长,其4个短芒野大麦种群的遗传多样性偏低,遗传距离较近,基因流较高,其分布明显符合距离隔离模型;而吉林省的5个种群都受到人类不同程度的干扰,大部分草原改为耕地或退化为重度盐碱地,形成了人为隔离,其遗传多样性偏高,遗传距离较远,基因流较低,其分布明显符合脚踏石模型。9个短芒野大麦天然种群分布在该物种地理分布的最东端,根据多样性分析,表明其迁移方向应为由南向北,即从松嫩平原南部的吉林省向北部的黑龙江省扩散。很明显,两种显性标记技术都适合高度异交短芒野大麦种群遗传多样性和遗传结构分化的研究,而对种群样本量的要求较低,每个种群大于16株的样本量就可以代表绝大部分种群遗传信息。但是从各种指标来看,S-SAP能检测到更多的变异,遗传多样性更高,更适合该物种种群分子遗传学研究。根据AFLP和S-SAP的分析结果,两种方法都把松嫩平原9个短芒野大麦天然种群的235个单株聚为3组,从3组中分别取出8个单株来分析3组共24个短芒野大麦单株的甲基化模式变化。很明显,松嫩平原短芒野大麦天然种群的甲基化模式具有种群特异性,采用聚类分析,能把绝大多数单株聚到相应的组中。另一方面,通过对AFLP、S-SAP、甲基化非敏感多态(Methylation-insensitive polymorphism: MSIP)和甲基化敏感多态(Methylation-sensitive polymorphism: MSP)Jaccard相似性系数的Mental相关性检测发现,短芒野大麦种群甲基化模式变化不仅与序列和反转座子序列变化有一定的相关,还受其它控制系统的调控。更多还原

【Abstract】 Genetic diversity and structure of 9 natural populations of wild barley (Hordeumbrevisubulatum (Trin.) Link.), which encomprised of a total of 235 individuals collected fromSongnen plain were analyzed by amplified fragment length polymorphism (AFLP),specific-sequence amplified polymorphism (S-SAP) and methylation-sensitive amplifiedpolymorphism (MSAP) markers. The efficiency of these three markers was also evaluated.Indices of genetic diversity, genetic distance, gene flow, genotype frequency, clusteranalysis, PCA analysis and AMOVA analysis generated from both AFLP and S-SAP markershad the same trend. It was determined that a sample number of 16 was enough to represent themajority of genetic diversity for a given population of wild barley. Grasslands in the Qiqihaerarea distribute broadly and were not isolated by geography such as mountains, or notdisturbed by human interferences, and this area is suitable for growth of wild barley too. Sogenetic diversity indices were lower, genetic distance between populations was smaller andgene flow among given populations was higher among these populations. Spatial structure ofthe four populations on Qiqihaer area was consistent with an isolation-by-distance model(r=0.80917 for AFLP data and r=0.95479 for S-SAP data). But loci of five populations in Jilinprovinces were interrupted severely by huamn activities, most of the plains have been turnedinto plowland or salinity/alkaline soil. Therefore, genetic diversity indices were higher,genetic distance between populations was larger and gene flow among populations was lowerin these populations. The spatial structure of 5 populations on Jilin area was consistent with astepping stone model. On the other side, the 9 natural populations of wild barley distribute onthe east peripheral area, the direction of migration of wild barley on Songnen plain maybefrom south (Jilin) to north (Heilongjiang) based on population diversity and structure. S-SAPis more suitable for detecting variety than AFLP after comparing indices of genetic diversitybetween them.The 235 wild barley indivuduals were clustered into three groups using UPGMA basedon AFLP and S-SAP Jaccard similarity indices (JSI) separately. Eight plants from each groupwere selected and analyzed by MSAP. First, The 24 MSAP-studied individuals can beclustered into their respective groups except for KZJ1 using MSP (Methylation-sensitivepolymorphism) JSI matrix by UPGMA (r=0.72864), suggests that methylation pattern of wildbarley population in Songnen plain is characteristic of each population. Second, themethylation pattern change is not only related to DNA sequence variation, but mayberegulated by other controlling systems from Mental test of JSI matrices of AFLP, S-SAP, MSPand MISP (Methylation-insensitive polymorphism).更多还原