Microsatellite markers for the common bean Phaseolus vulgaris

Efforts to develop molecular tools for genetic analysis and breeding of common bean in the tropics are still limited. The number of microsatellite markers available for the crop is small compared to other crops of similar social and economic importance. As part of a project to broaden the use of molecular tools in bean breeding, a genomic library enriched for AG/TC repeat sequences was constructed for Phaseolus vulgaris. Twenty microsatellite markers were initially developed and 10 were characterized using a panel of 85 representative accessions of the bean gene bank. The number of alleles per marker ranged from three to 10. The polymorphism information content (PIC) varied from 0.23 to 0.80. The results indicate that the new markers can be readily used in genetically analysis of common bean.     

Isolation and characterization of eight compound microsatellite markers in a mangrove tree Kandelia candel (L.) Druce

Kandelia candel is an important mangrove tree species of family Rhizophoraceae. Here we isolated eight codominant compound microsatellite simple sequence repeat (SSR) loci from K. candel. Our isolated loci provided compound SSR markers with polymorphism of three to 11 alleles per locus. The expected and observed heterozygosities ranged from 0.230 to 0.887 and from 0.083 to 1.00, respectively. These markers would be the useful tools for analysing questions concerning population genetic structure and mating system of K. candel.     

Use of molecular markers in participatory plant breeding: assessing the genetic variability in cotton populations bred by farmers

In participatory plant breeding, farmers are involved in simple selection schemes that are not suitable for assessing genetic variability in the segregating populations. We propose to use information derived from molecular marker analyses to help monitoring such populations. In this study, we used three indicators to compare genetic variability in eight genetic structures, that is three plant populations selected by farmers over five generations, three nonselected populations and two commercial varieties. The three indicators were the polymorphic locus rate, heterozygosity rate and dissimilarity index. The results highlighted that the genetic variability decreased more with farmers’ selection than with environmental factors. The breeding process was not complete because genetic variability in the selected populations was midway between that of the nonselected populations and that of the commercial varieties monitored. The three proposed indicators were relevant for describing the studied populations. They could be interpreted according to a grid drawn up on the basis of the results of the present study.     

PCR analysis of oilseed rape cultivars (Brassica napus L. ssp. oleifera) using 5′ -anchored simple sequence repeat (SSR) primers

Primers complementary to simple sequence repeats (SSRs) and with variable three-base anchors at their 5 end, were used in PCR analyses to compare pooled DNA samples from various Brassica napus and B. rapa cultivars. Amplification products were resolved on polyacrylamide gels and detected by silver-nitrate staining. The resulting banding patterns were highly repeatable between replicate PCRs. Two of the primers produced polymorphisms at 33 and 23 band positions, respectively, and could each discriminate 16 of the 20 cultivars studied. Combined use of both primers allowed all 20 cultivars to be distinguished. The UPGMA dendrogram, based on the cultivar banding profiles, demonstrated clustering on the basis of winter/spring growth habit, high/low glucosinolate content, and cultivar origin (i.e. the breeder involved). Intracultivar polymorphism was investigated using a minimum of ten individuals for each cultivar and was found to vary considerably between cultivars. It is concluded that anchored SSR-PCR analysis is a highly informative and reproducible method for fingerprinting oilseed rape populations, but that intra-cultivar variation should be investigated before using banding profiles from pooled samples for the identification of individuals.     

The medical utility of genomics data in neuropsychiatry: mutational genetics versus association genetics

The long anticipated ‘genetic revolution’ in neuropsychiatry has yet to have an impact on the practice of clinical medicine. Excitement in the 1980s over major genetic breakthroughs in schizophrenia and manic depression, for example, has been replaced in the late 1990s by the sobering realization that most common neuropsychiatric disorders are multifactorial. Despite considerable effort and resources, no ‘causative’ genetic variation has been identified that plays a definitive major role in any common neuropsychiatric disorder.     

两系杂交小麦恢复系MR168抗条锈病基因遗传分析及分子标记定位

小麦条锈病是影响杂交小麦普及推广的重要因素。文章利用基因推导法和SSR分子标记技术,研究了温光型两系杂交小麦恢复系MR168的抗条锈性遗传规律及其控制基因染色体位置。结果表明,MR168对CY29、CY31、CY32、CY33等条锈菌生理小种表现高抗至免疫;对SY95-71/MR168杂交组合的正反交F1、BC1、F2和F3群体分单株接种鉴定显示,MR168对CY32号小种的抗性受1对显性核基因控制,该抗病基因来源于春小麦品种辽春10号。利用集群分离分析法(Bulked segregant analysis,BSA)和简单重复序列(Simple sequence repeat,SSR)分子标记分析抗病亲本MR168、感病亲本SY95-71及183个F2代单株,发现了与MR168抗条锈病基因连锁的5个微卫星标记Xgwm273、Xgwm18、Xbarc187、Xwmc269、Xwmc406,并将该基因初步定位在1BS着丝粒附近,暂命名为YrMR168;构建了包含YrMR168的SSR标记遗传图谱,距离YrMR168最近的两个微卫星位点是Xgwm18和Xbarc187,遗传距离分别为1.9 cM和2.4 cM,这两个微卫星标记可用于杂交小麦抗条锈病分子标记辅助育种。     

干旱胁迫和正常灌溉条件下玉米产量性状的QTL分析

产量及其产量因子是衡量玉米耐旱能力的重要性状。本研究利用Lo1067×Y i72的F2∶3家系进行产量性状的数量性状位点(QTL)的分析。结果表明,在正常水分条件和开花期干旱胁迫条件下,分别有14个QTL与产量性状穗重、粒重、轴重、百粒重、穗数、穗粒数有关。此外,还检测到7个与抗旱指数(TI)相关的QTL。各QTL所解释的表型变异在1%~78%;这些QTL以部分显性和超显性为主。不同胁迫条件下检测到的QTL不一致,说明存在显著的QTL与环境互作。     

观赏羽衣甘蓝SSR标记分型与亲缘关系研究

观赏羽衣甘蓝凭借优良的观赏特性和抗逆性已经成为重要的冷季观赏植物。国内观赏羽衣甘蓝育种起步较晚,并且缺乏对种质资源遗传背景的系统研究。本研究应用SSR标记对不同类型的观赏羽衣甘蓝材料进行标记分型和亲缘关系分析。从99对均匀分布于甘蓝基因组的SSR引物中筛选出46对多态性好的引物,对27份不同类型的观赏羽衣甘蓝材料进行标记分型,共扩增出210个多态性位点,平均PIC值为0.58。进一步利用标记分型结果进行STRUCTURE群体结构、UPGMA聚类和聚类热图分析,结果显示3种分析结果基本一致,可以将27份材料分为圆叶、羽叶和皱叶3种类型,其中圆叶和羽叶类型的亲缘关系更近,与皱叶类型的亲缘关系较远;STRUCTURE分析还可以将双亲为不同类型的杂交种材料进行区分;聚类热图分析可以将标记分型结果形象的展示出来。本研究为进一步建立观赏羽衣甘蓝分子指纹图谱,明确种质资源的遗传背景,建立观赏羽衣甘蓝分子标记辅助选择育种体系,培育具有自主知识产权的新品种奠定基础。     

Genetic Diversity Analysis of Tibetan Wild Barley Using SSR Markers

One hundred and six accessions of wild barley collected from Tibet, China, including 50 entries of the two-rowed wild barley Hordeum vulgare ssp. spontaneum (HS), 29 entries of the six-rowed wild barley Hordeum vulgare ssp. agriocrithon (HA), and 27 entries of the six-rowed wild barley Hordeum vulgare ssp. agriocrithon var. lagunculiforme (HL), were analyzed using 30 SSR markers selected from the seven barley linkage groups for studying genetic diversity and evolutionary relationship of the three subspecies of Tibetan wild barley to cultivated barley in China. Over the 30 genetic loci that were studied, 229 alleles were identified among the 106 accessions, of which 70 were common alleles. H. vulgare ssp. spontaneum possesses about thrice more private alleles (2.83 alleles/locus) than HS (0.93 alleles/locus), whereas almost no private alleles were detected in HL. The genetic diversity among-subspecies is much higher than that within-subspecies. Generally, the genetic diversity among the three subspecies is of the order HS > HL > HA. Phylogenetic analysis of the 106 accessions showed that all the accessions of HS and HA was clustered in their own groups, whereas the 27 accessions of HL were separated into two groups (14 entries with group HS and the rest with group HA). This indicated that HL was an intermediate form between HS and HA. Based on this study and previous works, we suggested that Chinese cultivated barley might evolve from HS via HL to HA.     

通过不对称体细胞杂交向小麦转移青苗碱谷DNA

普通小麦"济南177"(Triticum aestivum L.cv.Jinan177)经继代培养和选择,形成了性质不同的愈伤组织,一种生长迅速,易于形成悬浮系,游离的原生质具有旺盛的分裂能力,但不能分化,称为Cha9;另一种具有一定能力,但游离原生质体分裂能力低,称为176.二者之一来源的原生质体与紫外线照射的青苗碱谷原生质体融合均不能获得再生植株.而将源于Cha9和176的两种原生质体混合,与经紫外线照射的青苗碱谷原生质体在PEG诱导下融合,融合产物再生了大量植株.再生的愈伤组织及植株经表现型、细胞学、有工酶、RAPD分析,证明了其杂种性质,用不麦叶绿体特异的简单得复序列(SSR)引物分析了再生杂种的叶绿体遗传组成情况.在不同的杂种克隆中,同时带有Cha9和176的遗传物质并含有供体核及胞质基因组的克隆4具有较高的分化能力,再生了大量生长旺盛的完整植株.