利用118对 SSR 分子标记对2012年云南哈尼梯田的47份水稻材料进行多态性检测,分析其遗传多样性,并利用Structure 2．3．4软件进行群体结构分析.结果显示,118对 SSR 标记共检测到255个等位变异,变幅为2～4个,平均每个标记2．161个.基因多样性指数变异范围为0．043～0．656,平均0．303.多态信息含量（PIC）变异范围为0．042～0．583,平均0？256.其中高度多态位点（PIC＞0．5）有2个,中度多态位点（0．25＜PIC＜0．5）有66个；通过遗传相似系数及基于数学模型的群体结构分析均将供试材料分为偏籼和偏粳2个类群；聚类结果和海拔高度总体上没有明显规律,但偏籼类群中的偏籼红米亚群按海拔高低分别聚在一起.研究表明,云南哈尼梯田现有栽培水稻以偏籼水稻为主,但本研究估测的遗传多样性低于前人报道.
Understanding genetic characteristics in rice populations will facilitate exploring evolutionary mechanisms and gene cloning. Numerous molecular markers have been utilized in linkage map construction and quantitative trait locus(QTL) mappings. However, segregation-distorted markers were rarely considered, which prevented understanding genetic characteristics in many populations. In this study, we designed a 384-marker Golden Gate SNP array to genotype 283 recombination inbred lines(RILs) derived from 93-11 and Nipponbare Oryza sativa crosses. Using 294 markers that were highly polymorphic between parents, a linkage map with a total genetic distance of 1,583.2 c M was constructed, including 231 segregation-distorted markers. This linkage map was consistent with maps generated by other methods in previous studies. In total, 85 significant quantitative trait loci(QTLs) with phenotypic variation explained(PVE) values?5% were identified. Among them, 34 QTLs were overlapped with reported genes/QTLs relevant to corresponding traits, and 17 QTLs were overlapped with reported sterility-related genes/QTLs. Our study provides evidence that segregation-distorted markers can be used in linkage map construction and QTL mapping. Moreover, genetic information resulting from this study will help us to understand recombination events and segregation distortion. Furthermore, this study will facilitate gene cloning and understanding mechanism of inter-subspecies hybrid sterility and correlations with important agronomic traits in rice.
Accumulating evidence has suggested that epigenetic marks including DNA methylation,small RNA and histone modification may involve hybrid vigor in plants.However,knowledge about how epigenetic marks in hybrids regulate gene expression is still limited.Based on genome-wide DNA methylation landscapes of Arabidopsis thaliana Ler and C24 ecotypes and their reciprocal F1 hybrids which were obtained in our previous work,we analyzed allele-specific DNA methylation and distinguished cis-and trans-regulated DNA methylation in hybrids.Our study indicated that both cis-and trans-regulated DNA methylation played roles in hybrids,when cis-regulation played a major role in CG methylation and trans-regulation played major roles in CHG and CHH methylation.In addition,we observed correlations between trans-regulated DNA methylation and siRNA densities.Enriched siRNA regions were significantly concurrent with highly trans-regulated DNA methylation regions.Our results illustrated DNA methylation regulation patterns integrated with siRNAs in Arabidopsis hybrids,and shed light on understanding the mechanism of epigenetic reprogramming for hybrid vigor.
