Chromosomal localization of five mutant genes in rice, Oryza sativa, using primary trisomics

The chromosomal locations of five mutant genes in rice were determined by crossing the marker stocks with the 12 primary trisomics. Genetic segregation of each gene was studied in the F₂ or backcross populations. Out of the 60 possible cross combinations, 43 F₂ or BC₁ populations were studied. Segregation data indicated that spl11 was located on chromosome 12 while wp2 and eg2_(t) were located on chromosome 6. The genes v12_(t) and Bc₆ were located on chromosomes 8 and 9, respectively, which are sparsely populated with genetic markers.     

A quick methodology to identify sexual seedlings in citrus breeding programs using SSR markers

In citrus breeding and genetics, it is very important to distinguish between zygotic and nucellar seedlings in order to eliminate unwanted genotypes. Usually, isozyme marker shave been employed to determine the genetic origin of young plants. In this work we propose the use of SSR markers as an alternative methodology and compare them with isozymes in this kind of screenings. Two different populations were analysed: one derives from an interspecific cross and the other from selfing. We conclude that, in most cases, microsatellites are more efficient than isozymic markers to identify the sexual origin of citrus seedlings, given their higher level of polymorphism and the scarce number of polymorphic isozymes in some populations. We describe a quick and efficient methodology for SSR analysis, including a fast DNA extraction in microcentrifuge tubes, and visualization through silver staining, which eliminates the need for a labelling step. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic analysis of resistance in barley to barley yellow dwarf virus

The inheritance of resistance to barley yellow dwarf virus (BYDV) was studied in the selected 24 spring and winter barley cultivars that showed a high or intermediate resistance level in 1994‐97 field infection tests. The polymerase chain reaction diagnostic markers YLM and Ylp were used to identify the resistance gene Yd2. The presence of the Yd2 gene was detected with both markers in all the resistant spring barley cultivars and lines from the CIMMYT/ICARDA BYDV nurseries. The results of field tests and genetic analyses in winter barley corresponded with marker analyses only when the Ylp marker was used. Genes non‐allelic with Yd2 were detected by genetic analyses and the Ylp marker in moderately resistant spring barley cultivars ‘Malvaz’, ‘Atribut’ and ‘Madras’, and in the winter barley cultivars ‘Perry’ and ‘Sigra’. Significant levels of resistance to BYDV were obtained by combining the resistance gene Yd2 with genes detected in moderately resistant cultivars. The utilization of analysed resistance sources in barley breeding is discussed.     

Random amplified polymorphic DNA (RAPD) analysis for the verification of hybridity in interspecific crosses of Alstroemeria

Random amplified polymorphic DNA (RAPD) markers were used to verify interspecific hybridization in Alstroemeria. Five putative interspecific hybrids and their parents were analysed by means of four preselected RAPD primers. The putative parentage was confirmed in four hybrids and was excluded in one that showed completely different RAPD patterns from its putative parents and a different phenotype. Our results demonstrated that this molecular technique is a powerful tool for verifying hybridity rapidly if the putative parents are given. This tool will allow screening of small immature seedlings for verification of hybridity and should improve the efficiency of breeding programmes.     

Development of simple sequence repeat (SSR) markers in Eucalyptus from amplified inter-simple sequence repeats (ISSR)

Eucalyptus spp. are widely used in exotic plantations. Since many of these trees are derived from vegetative propagation, the routine identification of clones has become increasingly important. The most widely used molecular based method for fingerprinting these clones is by random amplified polymorphic DNAs (RAPDs). Although this technique is useful, its results are not very repeatable, especially between laboratories. The aim of this study was to develop microsatellite markers that are highly repeatable, and to investigate their value in Eucalyptus fingerprinting. Typically, this process involves the expensive procedure of constructing an enriched genomic library. However, we used an intersimple sequence repeat (ISSR) polymerase chain reaction (PCR)‐based enrichment technique for microsatellite‐rich regions. With this relatively inexpensive method, microsatellite‐rich regions were amplified directly from genomic DNA, after which PCR products were cloned and sequenced. From these microsatellite‐rich sequences, primer sets were constructed to amplify mono‐, di‐, tri‐, hexa‐and nona‐nucleotide repeats. These markers were all inherited in a Mendelian fashion in the progeny of a test cross between two Eucalyptus grandis trees. The primer sets developed were also able to amplify the corresponding microsatellite loci from five different Eucalyptus spp., namely E. grandis, E. nitens, E. globulus, E. camaldulensis and E. urophylla.     

甘蓝型油菜Pol CMS育性恢复基因的RAPD标记

采用恢、 保回交群体和集团分离分析(BSA), 筛选了860个10 mer随机引物, 找到了与甘蓝型油菜波里马细胞质雄性不育系(Pol cms)育性恢复基因(Rf)连锁的两个RAPD标记AH19690和AI16830。 它们位于Rf的一侧,与该基因的遗传图距分别为5.9 cM和13.6 cM,两标记间的遗传图距为7.8 cM。这两个RAPD标记的发掘,为进一步利用分子标记     

郏县红牛全基因组测序分析及关键基因SNP分子标记在育种的应用研究

为了更好地扩展对郏县红牛基因组变异的研究,开发更多有效的分子标记,达到促进郏县红牛的进一步选育改良的目标。本研究对30头郏县红牛进行了全基因组重测序,分析了郏县红牛的基因组变异情况,并结合查阅文献筛选影响重要经济性状的遗传变异,检测这些变异在郏县红牛群体中的分布情况。并同时通过实验在3头郏县红牛中加以验证,为郏县红牛的保种与淘汰提供一定的理论依据。     

改进的DNA指纹技术在玉米杂交种纯度鉴定上的应用研究

本试验以幼苗为对照,利用CTAB法建立了一套简单、快速的玉米干种子DNA提取程序,该程序提取的DNA分子量大小与幼苗法相当,能够利用SSR引物进行扩增,可应用于玉米杂交种纯度检测。     

基于高通量测序技术挖掘分子遗传标记及其在蛋鸡生产中的精准应用

高通量测序技术是研究物种复杂生物性状遗传机制的基础,随着高通量测序技术的不断优化提升,一些与生物表型性状密切相关的基因组变异被精准地挖掘出来,其中包括单核苷酸多态位点(SNP)、小片段的插入或缺失(Indel)、拷贝数变异(CNV)以及结构变异(SV)为代表的分子标记。与传统遗传标记相比较,分子遗传标记具有多态性高、遍布整个基因组、检测手段简单快捷以及成本低廉的特点。通过检测覆盖全基因组范围内的分子标记,利用基因组水平的遗传信息对个体或群体遗传资源进行评估,能够缩短世代间隔、提高选种的准确性,进而在短期内取得较大的遗传进展。作者从高通量测序技术挖掘分子遗传标记角度入手,综述了三代测序技术发展历程和应用领域以及三代分子遗传标记检测技术在蛋鸡种业创新中的应用,并详细阐述了高通量测序技术与分子遗传标记相结合在蛋鸡群体遗传多样性及进化分类、群体遗传图谱的构建和功能基因定位、数量性状形成的遗传机制解析和质量性状形成的遗传机制解析等4个方面的精准应用,以期为蛋鸡基因组选择进入实质应用阶段提供科学依据和指导。     

山杏种源试验与选择初步研究

通过对山杏进行种源苗期、林期试验和RAPD分子标记实验,结果表明:种源间苗高、地径、冠幅等性状存在极显著差异,且广义遗传力较高;内蒙古东西部山杏种源间差异明显;山杏性状间具有相关性;初步选择出敖汉旗为最佳种源;种源间遗传分化程度较高,种源内遗传多样性排序为敖汉旗>巴林右旗>乌拉山>万家沟。本文为山杏遗传改良和合理开发利用提供了研究基础和科学依据。