An Improved Brassica rapa Genetic Linkage Map and Locus-specific Variations in a Doubled Haploid Population

In this study, we describe the construction of an improved Chinese cabbage genetic linkage map by integrating simple sequence repeats (SSRs) and insertion/deletion polymorphisms (InDels) into a previously published map of a doubled haploid (DH) population. The population was derived from a cross between the Chinese cabbage line BY (Brassica rapa ssp. pekinensis) and a European turnip line MM (Brassica rapa L. ssp. rapifera). A total of 629 markers were aligned to ten linkage groups, with a total map length of 1,173.8 cM, and an average distance between markers of 1.87 cm. Of the 126 SSRs and 133 InDels mapped, 46 and 34 were novel, respectively. A comparison of the linkage map with the B. rapa genome showed that more than 93 % of the markers, including 112 SSRs and 129 InDels, could be anchored unambiguously to a specific location on one of the ten chromosomes. In most cases, the order of markers on the linkage map and physical map was similar; however, the majority of linkage groups contained a number of markers whose positions were either transposed or had moved slightly forwards or backwards. During microspore culture, it was observed that 11 SSRs and one InDel showed either variation in size, or the appearance of new marker bands in the DH lines. As a first step to addressing this SSR/InDel marker instability, six SSR and one InDel loci were sequenced, which revealed that the size variation was due mainly to changes in repeat-motif number or to the insertion/deletion of new fragments of DNA.     

利用双单倍体群体剖析水稻产量及其相关性状的遗传基础

主效QTL、上位性效应和它们与环境的互作(QE)都是数量性状的重要遗传因素。利用籼粳交珍汕97／武育粳2号F1植株上的花药进行组织培养得到的190个双单倍体群体和179个微卫星标记,通过两年两重复田间试验,采用混合线性模型方法分析了9个控制水稻产量及其相关性状的遗传效应,得到57个主效QTL,41对上位性互作,8对QTL与环境的互作和7对上位性效应与环境的互作。单个主效QTL解释这些性状1．3％～25．8％的表型方差。各性状QTL的累积表型贡献率达11．5％～66．8％。大多数性状之间具有显著的表型相关性,相关性较高的性状之间常具有较多共同或紧密连锁的QTL。结果表明,基因的多效性或紧密连锁可能是性状相关的重要遗传基础。     

Genetic Molecular Linkage Map Construction and Genome Analysis of Rice Doubled Haploid Population

A high density genetic linkage map comprised of aA. 4 loci was constructed from a doubled haploid population derived from a inter-subspecific cross between an Oryza satire L. ssp. Indica vari.t.v ("Zhaiyeqing 8") and a japonica variety ("Jingxi 17"). The genetic map consisted of 276 RFLP markers, 34 RAPD markers, 89 microsatellite markers, 10 AFLP markers, 26 markers based on telomeric repetitive associated sequence (TAS) and 9 isozyme markers. This genetic map was highly comparable with other high density rice genetic maps and had its unique feature which meritted it suitable for sustained genetic analysis.     

Genetic Analysis of Carbon Isotope Discrimination and its Relation to Yield in a Wheat Doubled Haploid Population

Carbon isotope discrimination (Δ¹³C) is considered a useful indicator for indirect selection of grain yield (GY) in cereals. Therefore, it is important to evaluate the genetic variation in Δ¹³C and its relationship with GY. A doubled haploid (DH) population derived from a cross of two common wheat varieties, Hanxuan 10 (H10) and Lumai 14 (L14), was phenotyped for Δ¹³C in the flag leaf, GY and yield associated traits in two trials contrasted by water availability, specifically, rain‐fed and irrigated. Quantitative trait loci (QTLs) were identified by single locus and two locus QTL analyses. QTLs for Δ¹³C were located on chromosomes 1A, 2B, 3B, 5A, 7A and 7B, and QTLs for other traits on all chromosomes except 1A, 4D, 5A, 5B and 6D. The population selected for high Δ¹³C had an increased frequency of QTL for high Δ¹³C, GY and number of spikes per plant (NSP) when grown under rain‐fed conditions and only for high Δ¹³C and NSP when grown under irrigated conditions, which was consistent with agronomic performance of the corresponding trait values in the high Δ¹³C progeny; that is, significantly greater than that in the low Δ¹³C. Therefore, selection for Δ¹³C was beneficial in increasing grain yield in rain‐fed environments.     

籼粳杂种双单倍体的配子选择

对典型的灿与粳稻杂种,窄叶青８号／京系１７Ｆ１花药进行培养获得的１３２个双单倍体的形态特性、同工酶与ＲＦＬＰ标记的分离与重组进行了考察分析,研究是否存在配子选择问题。结果表明：（１）对４个重要数量性状和６个涉及籼、粳特征的形态指数进行考察所获数据均为连续分布,并呈正态曲线;（２）用８种同工酶对５２个ＤＨ系分析结果表明,只有２种同工酶显著偏离期望的１：１比率,而灿与粳的总基因型比率相近;（３）应用１６７个ＲＦＬＰ标记对１３２个ＤＨ系进行的分析发现,有３６％标记发生偏分离,但偏籼与偏粳的比率相近,两个亲本基因组在ＤＨ群体中所占比率相同（各５０％）,各种基因组成呈正态分布。综上所述,本研究虽观察到一些轻微偏分离现象,但籼粳基因基本上随机分离与重组,等位基因总频率未偏离１：１比率。     

Association between Rdna Alleles and Quantitative Traits in Doubled Haploid Populations of Barley

Doubled haploids (DH) were generated from reciprocal F1 hybrids which were heterozygous for alleles at the Nor-H3 locus on chromosome 5H of barley. The r-DNA alleles did not deviate significantly from the expected 1:1 ratio and the DH progenies were classified into two groups based on the allelic constitution of the Nor-H3 locus. The DHs were grown in a randomized, replicated field experiment and a range of agronomic and quality traits were recorded. The Nor-H3 locus was associated with a significant portion of the genetic variation for: yield, thousand corn weight, water sensitivity and milling energy requirement of the grain. However, the magnitude of the differences between groups was dependent on the direction of the cross. The milling energy requirement of the grain was consistently associated with alleles at the Nor-H3 locus. These results are presented in relation to the dynamics of rDNA evolution and variability. The potential of molecular markers in conjunction with doubled haploids to map quantitative traits in barley is also discussed.     

中国人HLA纯合细胞的筛选及纯合性鉴定

本文报告了我们实验室在中国人中筛选HLA纯合子的方法和筛选流程。用HLA血清学分型法,从上海129个近亲婚配家庭中筛选到HLA-AB纯合子23个(分布于17个家庭)。其中19个HLA-AB纯合子(分布于14个家庭)进一步做了家系MLC棋盘。最终证明,它们中14个细胞(分布于10个家庭)的HLA-D位点也纯合。     

The Effects of Temperature and Light Intensity on Embryo Numbers in Wheat Doubled Haploid Production through WheatxMaize Crosses

Triticum aestivumxZea mayscrosses are now widely used in theproduction of wheat doubled haploids to produce homozygous lines.Seasonal effects are known to influence the number of haploidembryos produced through wheatxmaize crosses, but the effectsof temperature and light have not been quantified. This studyinvestigated the effect of temperature and light intensity onhaploid embryo production. New Zealand wheat cultivars weregrown in a glasshouse until booting when they were transferredto growth cabinets at three temperatures (day/night; 17/12,22/17 or 27/22 °C at an irradiance of 250 µmol m^-2s^-1PAR).In another experiment, wheat lines were transferred to a growthcabinet at one of three light intensities (300, 500 or 1000µmol m^-2s^-1PAR at 22/17 °C day/night, with a photoperiodof 16 h). The temperature and light intensity at which pollinationswere made and subsequent fertilisation and embryo developmentoccurred, significantly (P<0.01) influenced the frequencyof haploid embryo production. The optimal temperature for embryorecovery was 22/17 °C. The greatest number of embryos wasproduced at a light intensity of 1000 µmol m^-2s^-1. Thesefindings will result in improvements in the overall efficiencyof the wheatxmaize system for wheat doubled haploid production.Copyright1998 Annals of Botany Company Intergeneric crossing, temperature, light intensity,Triticum aestivum,wheat,Zea mays,maize.     

小麦幼苗磷利用率及相关基因的染色体定位

利用小麦'中国春-埃及红'代换系对调控不同水分和磷素胁迫处理下磷素利用效率及相关性状进行了染色体定位和遗传分析,为作物磷素高效利用的遗传改良研究奠定基础.结果表明,染色体7A和7D代换系在Hoagland营养液(WP)、10% PEG-6000 Hoagland营养液(-WP)、1/2P Hoagland营养液(W-P) 处理下,可能携带有对磷素利用有促进作用的基因.遗传分析表明,磷素利用率的遗传力、遗传进度、相对遗传进度都较高,说明该性状的变异由遗传作用引起的比重较大,环境因素对它的遗传影响不大,适合在遗传育种中进行早代选择.     

普通小麦基因组中耐低磷胁迫特性的染色体控制

以普通小麦中国春的一套缺四体为材料,对其耐低磷胁迫特性进行鉴定和遗传分析。结果表明：（１）第１,４,７部分同源群与低磷胁迫特性关系最密切,且第１,７部分同源群内各染色体间在该性状的遗传互补性良好。第４部分同源群则不同,４Ａ可以有效补偿４Ｂ与４Ｄ的缺失,反之则不能。（２）第２,３,５６部分同源群与低磷胁迫特性关系不密切,且这些同源群内某一染以体的缺失大多不能被其他染色体有效地补偿,尤其是第３与第６部     

腾冲热海一株嗜酸热硫化叶菌的分离与鉴定

从云南腾冲热海酸性温泉中分离纯化出一株极端嗜酸热菌株K4-1,并对其进行形态观察、生长特征、碳源和能源利用及16S rRNA基因分析.该菌株细胞形态为不规则球形,有单生鞭毛,严格好氧,兼性自养,能利用元素硫作为能源,也能利用酵母膏、精氨酸或核糖作为碳源和能源.其最适生长温度为75℃,最适pH为3.5.通过16S rRNA基因序列相似性对比对该菌株进行鉴定,结果表明该菌株与硫化叶茵属标准菌株的相似性介于86.6%～94.3%之间,与分离自腾冲热海的腾冲硫化叶菌Sulfolobus tengchongensis RT8-4菌株序列相似性最高,达到98.9%,可将菌株K4-1鉴定为硫化叶菌属菌株.菌株K4-1的16S rRNA基因序列号为EU729124.     

Synchrony in a Wild Turkey Population and its Relationship to Spring Weather

Abstract: Synchrony is an important component of wildlife population dynamics because it describes spatial pattern in temporal population fluctuations. The strength and spatial extent of synchrony can provide information about the extrinsic and intrinsic forces that shape population structure. Wild turkey (Meleagris gallopavo silvestris) populations undergo annual fluctuations, possibly due to variation in weather during the reproductive season. To determine if spring weather plays a role in synchronizing wild turkey populations, we used a modified Mantel-type spatial autocorrelation procedure to measure the synchrony in fall wild turkey harvest data collected in 443 townships from 1990 to 1995 and compared this to the pattern of synchrony in spring weather variables (May rainfall and temp) over the same period. We measured correlation using Spearman correlation coefficients between the total fall harvests from 1990 to 1995 for each pair of townships, and sorted pairs into 6 50-km distance intervals. We calculated a mean correlation coefficient for each interval and estimated its P-value using resampling. We found moderately significant synchrony in the fall harvest (r_s = 0.12-0.34, P < 0.008) among township pairs <150 km apart, but no significant synchrony beyond this distance. In contrast, both May temperature (r = 0.82-0.90, P < 0.001) and rainfall (r = 0.49-0.76, P < 0.001) were strongly synchronized across all 6 distance intervals. Visual inspection of time series in the wild turkey fall harvest suggests that populations may be synchronized in some years when weather promotes high reproductive success (i.e., a synchronized growth peak) and asynchronous in other years. Knowledge of the spatial dynamics of wild turkey populations will aid wildlife managers in estimating population change, setting harvest quotas, and managing habitat.     

No Observable Relationship Between the 12 Genes of Nervous System and Reasoning Skill in a Young Chinese Han Population

Reasoning skill is an advanced cognitive ability which is needed for drawing inferences from given information. It is well known that the ability depends on the neural network of the frontal and parietal brain regions. In this study, we hypothesized that some genes involved in neurotransmitter systems were related to reasoning skill. To confirm this hypothesis, we examined the effects of 13 genes (BDNF, NRSF, COMT, DBH, DRD ₂ , DRD ₃ , DAT ₁ , MAOA, GRM ₁, GRIN2B, TPH ₂ , 5-HT _2A , and 5-HT ₆ ) in neurotransmitter systems on the non-verbal reasoning and verbal reasoning skills. The results indicated there were on significant effects of the 17 functional variants of these genes on the performance of non-verbal reasoning and verbal analogical reasoning skills (χ² > 3.84, df = 1, P > 0.05). This study suggests that some of the functional variations in BDNF, COMT, DBH, DRD ₂ , DRD ₃ , MAOA, 5-HT _2A , 5-HT ₆ , GRM ₁ , and GRIN2B have no observable effects on the certain reasoning skills in a young healthy Chinese Han population.     

应用AFLP与RFLP标记研究水稻磷吸收与利用率的数量性状位点

To identify genetic factors underlying phosphorus (P) uptake and use efficiency under low-P stress in rice (Oryza sativa L.), 84 selected genotypes (recombinant inbred lines) and their parents (which differed in tolerance for low-P stress) “IR20” and IR55178-3B-9-3, were cultured in liquid medium supplemented with adequate and low P levels in a greenhouse. Plants were sampled after 6 weeks in culture for measurements of plant dry weight, P concentration, P uptake and P use efficiency under both P sufficient and stress conditions. A total of 179 molecular markers, including 26 RFLPs and 153 AFLPs, mapped on all 12 chromosomes of rice based on the 84 selected genotypes were used to detect the quantitative trait loci (QTLs) underlying tolerance for low-P stress. Three QTLs were detected on chromosomes 6, 7 and 12, respectively, for relative plant dry weight (RPDW) and relative P uptake (RPUP). One of the QTLs flanked by RG9 and RG241 on chromosome 12 had a major effect which explained about 50% of the variations in the two parameters across the population. The results coincided with the QTLs for low-P stress based on relative tillering ability from the same population from a cross between Nipponbare and Kasalath under soil condition. The identical major QTL for P uptake and plant growth under low-P stress in both liquid medium and soil strongly suggests that the ability of P uptake mainly controls rice tolerance for low-P stress.     

应用AFLP与RFLP标记研究水稻磷吸收与利用率的数量性状位点

从耐低磷胁迫水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）品种“ＩＲ２０”与低磷敏感品质ＩＲ５５１７８－３Ｂ－９－３杂交发展的重组自交系群体中选择的８４个系在液体培养条件下,测定了相对生物量,植株相对磷含量及相对磷利用率;在酸性土壤盆栽条件下测定了相对分蘖力与相对地上部生物量。用选择的８４个系构建了包括２６个ＲＦＬＰ标记与１５３个ＡＦＬＰ标记的分子标记图谱用于基因定位分析。溶液培养条件下在第１２,６,７三     

Genetic Mapping of Rice Using RFLP Markers and a Double Haploid Population of a Cross Between indica and japonica Varieties

A genetic linkage map of rice was constructed using a double haploid (DH) population from "Gui 630” (Oryza sativa subsp, indica)/"02428" (O. sativa subsp, japonica, wide compatibility variety) and RFLP markers. It consists of 233 loci and covers rice genomes about 2070 cM (centimorgan), and compares well with the other published rice maps. 25 RFLP markers, 2 telomeres and sh-2 (shattering ability) gene were first located on the molecular map of rice. RFLPs between "Gui 630' and "02428' mainly came from base substitution and a few DNA construction variance, not distributed evenly among chromosomes and on chromosome. This was probably resulted from the difference genetic stability among chromosomes and regions, in exchanging recombination ability in different segments of chromosome.     

QTL Analysis in Recombinant Chromosome Substitution Lines and Doubled Haploid Lines Derived from a Cross between Hordeum vulgare ssp. vulgare and Hordeum vulgare ssp. spontaneum

Recombinant chromosome substitution lines (RCSLs) were developed in BC₃ generation to introduce segments of a wild barley strain ‘H602’ (Hordeum vulgare ssp. spontaneum) into a barley cultivar ‘Haruna Nijo’ (H. vulgare ssp. vulgare) genetic background. One hundred thirty four RCSLs were genotyped by 25 SSR and 60 EST markers, which were localized on a linkage map of doubled haploid lines (DHLs) derived from the same cross combination. Graphical genotyping revealed that the observed average substitution ratio of H602 segment (12.9%) agreed with the expected substitution ratio (12.5%), and a minimum set of 19 RCSLs represented the entire H602 genome. Phenotypes of five qualitative and nine quantitative traits were scored in both the RCSLs and DHLs. Five qualitative traits were localized as morphological markers on the linkage map of the DHLs, and these molecular markers were aligned on the respective chromosomal regions in the RCSLs. Simple and composite interval mapping procedures detected a total of 18 and 24 QTLs for nine qualitative traits on the RCSLs and DHLs, respectively. Several QTLs were localized at coincident or very close regions on both linkage maps. In spite of general inferior agronomic performances in wild barley, several H602 QTL alleles showed agronomically positive effects. These RCSLs should contribute to substitution of favorable alleles from wild barley into cultivated barley. These RCSLs are also available as sources of near isogenic lines, with which we can apply advanced genetic analysis methods such as isolation of QTLs and detection of epistatic interactions among QTLs.