大白×梅山杂交组合肉质性状的数量性状位点定位分析

为寻找影响猪肉质数量性状基因位点的染色体区域 ,以 3头英系大白公猪和 7头梅山母猪建立F2 资源家系。随机选留 14 7头F2 代个体 (1998年 81头 ,2 0 0 0年 66头 ) ,经检测均获得肉质性状表型数据。对资源家系内的所有个体位于染色体 1、2、3、4、6和 7上的 48个微卫星位点进行扩增。利用线性模型最小二乘法分别对各年度及两年综合后的肉质性状进行数量性状位点 (QTL)区间定位 ,利用置换法确定显著性阈值。研究结果表明 :在 2 0 0 0年群体中 ,猪 4号染色体 (SSC4)上定位了肌内脂肪QTL ,达到染色体极显著水平 (P <0 0 1)和基因组显著水平 (P <0 0 5) ,解释表型变异为 5 2 4% ,梅山猪具有增加肌内脂肪QTL ;两年度群体综合后 ,在上述 4号染色体同一区间 ,肌内脂肪QTL接近染色体显著水平 ;股二头肌pH值和半棘肌pH值QTL分别定位在SSC1和 3上 ;在 1998年和 2 0 0 0年群体中分别发现 1个和 3个达染色体显著水平 (P <0 0 5)的系水力QTL ;在 1998年群体中 ,肌肉含水量QTL位于SSC6;两年综合群体中 ,SSC2、6和 7上定位了肌肉含水量QTL ,达到染色体显著水平 ,含水量QTL均有印迹效应 ,梅山和大白猪各有增效基因     

猪2号染色体遗传连锁图谱的构建与QTL定位分析

构建了猪2号染色体的遗传连锁图谱,并进一步进行了重要生产性状数量性状位点的定位,结果表明,7个微卫星位点均为中高度多态性位点,多态信息含量为0．40182－0．58477,可以满足遗传连锁图谱构建的要求,构建的资源家系遗传连锁图谱总长152．9cM,位点的排列顺序与USDA结果一致,但除了Sw2516与Sw1201标记区间外,所有标记区间距离均大于USDA图谱,将连锁图谱与性状记忆结合起来,进一步进行了猪数量性状位点定位的研究,在2号染色体发现了显著影响活体估测瘦肉率等活体估测性状的QTLs,此外还发现眼肌高度和背最长肌大理石纹的QTLs,其中影响活体估测瘦肉率的QTL达到了染色体显著的水平（P＜0．01）,且解释性状的表型变异达21．55％,影响眼肌高度和背最长肌大理石纹的QTLs分别可以解释10．12％和10．97％的表型变异,影响活体估测性状的QTLs加性效应与显性效应作用方向相反,影响眼肌高度的QTL加性效应与显性效应相同,在大白猪中具有增效等位基因,定位的QTLs效应较大,为在群体中开展分子标记辅助育种奠定了理论基础。     

大白×梅山猪资源家系生长性状QTL的检测

以大白猪和梅山猪为父母本建立F2 资源家系 ,在 2 0 0 0年 ,随机选留 6 6头F2 代个体 ,获得出生重、6 0日龄体重、出生至 6 0日龄平均日增重及 6 0日龄至屠宰前平均日增重的表型数据。结合 4 8个微卫星标记构建的猪 1、2、3、4、6和 7号染色体遗传连锁图谱 ,用线性模型最小二乘法对各数量性状进行QTL区间作图 ,利用置换法(permutation)确定显著性阈值。研究发现 ,猪 4号染色体上有一个染色体水平极显著 (P <0 0 1)的QTL影响 6 0日龄至屠宰前平均日增重 ,并达到基因组显著水平 (P <0 0 5 )。在染色体水平 ,出生至 6 0日龄平均日增重QTL位于 2号染色体 ,6 0日龄体重QTL位于 1号染色体。 6号染色体的出生至 6 0日龄平均日增重QTL达到建议显著水平     

油菜油分、蛋白质和硫苷含量相关性分析及QTL定位

为定位与油分、蛋白质和硫苷含量等品质性状相关的数量性状位点（QTL）,以2个含油量较高的甘蓝型油菜（Brassica napus）品系8908B和R1为研究材料,配置正反交组合。在正反交F2代群体中,含油量和蛋白质含量都存在极显著的负相关,相关系数分别为-0．68和-0．81,含油量和硫苷含量相关性不显著：蛋白质含量和硫苷含量在正交群体中相关性不显著,但在反交群体中存在显著负相关（相关系数r=-0．45）。利用正交F2代群体中的118个单株,构建了包含121个标记的遗传连锁图谱,图谱长1298．7cM,有21个连锁群（LGs）。采用复合区间作图法,在连锁图上定位了2个与含油量有关的QTL,分别位于LG8和LG10,其贡献率分别为4．8％和13．7％,增效基因都来源于R1;定位了2个与蛋白质含量有关的QTL：pr01和pr02,分别位于LG1和LG3,其贡献率分别为15．2％和14．1％,位点pr07由8908B提供增效基因,pro2则由R1提供增效基因：定位了4个与硫苷含量有关的QTL,其中LG20上有2个,LG4和LG8上各1个,它们的贡献率在1．9％-25．4％之间,除LG20上glu7的增效基因来自R1外,其余3个QTL位点均由8908B提供增效基因。     

利用商品猪群定位猪耳型QTL

由 19头杂种公猪 [皮特兰× (皮特兰×汉普夏 ) ]、5 2头杂种母猪 [Leicoma× (大约克×长白 ) ]及其 332头后代组成的商品群作为参考家系 ,选择 172个微卫星标记和 3个 1类标记 (RYR1、PRKAG3、PIT1)对参考家系的个体进行遗传标记分型 ,构建了猪的整个基因组微卫星连锁图谱。按照线性评分的方法 (竖耳 :1分 ;垂耳 :- 1分 ;半垂耳 :0分 )测定猪的耳型表型值。耳型测定值的平均值为 0 .2 3,标准差为 0 .82。应用最小二乘回归方法对耳型的QTL进行定位 ,结果仅在 6号染色体的末端 (Sw1881和Sw32 2 )之间以 1%基因组显著性水平检测出 1个耳型基因位点 ,而在其他染色体上即使 10 %染色体显著性水平上也没有发现QTL。     

水稻F2不育和抽穗期QTL分析

对台中65（粳稻）/Bhadua（籼稻）杂交F2代群体构建了RFLP连锁图谱,含94个分布较为均匀的标记。对F2小穗不育性状进行单点分析和区间分析的结果基本一致：有两个F2小穗不育QTL座位分别位于染色体1的XNpb113～XNpb346之间和染色体8的G187～XNpb397之间,而且该两个QTL均为新检测出的座位;检测出5个抽穗期TQL,其中3个座位在单点分析和区间分析中的结果一致,分别位于染色体1的XNpb113～XNpb346,染色体4的C891～C335,染色体的8的C166～C1121,另外,染色体6的XNpb27为单点分析结果,染色体10的R716～C405为区间分析结果。由于染色体1上的F2不育QTL和抽穗期QTL重叠,该QTL座位是由于遗传效应所至还是由于环境因素（迟抽穗）所至有待构建近等基因系进一步研究。;位于染色体1和10上的抽穗期QTL座位为新检测的座位。对新检测的F2不育和抽穗期QTL座位正在建立相应的近等基因系以精确定位和克隆上述基因。     

玉米叶绿素含量的QTL定位

为了探讨玉米叶绿素含量的遗传规律, 以A150-3-2×Mo17杂交组配的189个F2单株作为作图群体, 构建了具有112个标记位点的玉米分子遗传图谱, 于喇叭口期和开花期分别进行了玉米叶绿素a含量(chla), 叶绿素b含量(chlb), 其他叶绿素含量(chlc)和叶绿素总含量(chlz)4个性状的测定, 并进行QTL分析。在喇叭口期和开花期共检测到32个QTL, 分布在除第6和10染色体以外的其他染色体上。在喇叭口期检测到24个QTL, 分布于第1、2、3、5、7、8和9染色体上, 叶绿素a、叶绿素b、其他叶绿素和叶绿素总含量各检测到6个QTL, 在同一区间内检测到的4个性状的QTL之间的距离在0~2 cM之间。喇叭口期检测到控制叶绿素a、叶绿素b、其他叶绿素和叶绿素总含量的4个主效QTL位于第5染色体上的umc1098~bnlg557区间, 分别可解释表型变异的11.63%、10.3%、10.77%和11.51%。开花期检测到8个QTL, 分布于第4和5染色体上。其中叶绿素a、叶绿素b、其他叶绿素和叶绿素总含量各2个QTL。标记umc1098和bnlg557之间同时存在控制喇叭口期4个叶绿素含量性状的QTL和开花期控制叶绿素a和叶绿素b的QTL。标记umc2308和bnlg386之间只存在控制开花期4个叶绿素含量性状的QTL。     

水稻籼粳亚种间杂种低温花粉不育的QTL分析

为探明籼粳杂种低温花粉不育的遗传基础,以籼稻品种3037和粳型广亲和品种02428的F2分离群体进行了低温花粉不育的遗传分析。推迟播种后,F2群体各单株孕穗期的日平均温度为21～23℃,调查了F2群体各单株的花粉育性。利用108对SSR引物构建了包含157个F2单株,覆盖12条染色体的分子标记连锁图谱。该连锁图的总长度为1857．8cM,标记间平均距离为16．26cM,标记较均匀地分布在12条染色体上。采用区间作图法对F2群体花粉不育进行QTL分析,共检测到2个低温花粉不育QTLS,即qLTSPS2和qLTSPS5,分别位于第2、5染色体,其加性效应分别为0．021、0．045,显性效应分别为-0．246、-0．251,显性度分别为11．7和4．8,具有超显性效应．超显性是QTL作用的主要方式,这2个位点杂合基因型在低温环境下具有降低花粉育性的作用,分别解释表型变异的15．6％、11．9％。另外,两因素的方差分析表明这两个QTL之间不存在互作。     

水稻光合功能相关性状QTL分析

利用粳稻Kinmaze／籼稻DV85杂交后代单粒传衍生的81个F11家系所组成的重组自交系（Recombinant Inbred Lines,RILs）群体,研究水稻光合功能相关性状的数量性状基因座（QTL）。在水稻抽穗后7d测定叶片全氮含量（TLN）、叶绿素a／b比值（Chl．a：b）和叶绿素含量（Chl）。共检测到6个QTL,各QTL的LOD值为2．66～4．81,贡献率为11．2％-29．6％,其中,在第1、2和11染色体上检测到3个与全氮含量相关的QTL,相应贡献率为17．3％、15．3％、13．7％;在第3和4染色体检测到2个与叶绿素a／b比值相关的QTL,贡献率为13．8％和29．6％;在第1染色体检测到1个与叶绿素含量相关的QTL,贡献率为11．2％。4个QTL为本研究新检测的基因座。有趣的是,控制叶绿素含量的qCC-1位于第1染色体上RFLP标记C122附近,与已报道的NADH-谷氨酸合成酶基因位置一致,而叶绿素合成始于谷氨酸,暗示该基因座与水稻光合功能关系极为密切。然而,对抽穗后30d叶绿素含量进行QTL分析,结果未检测到与其相关的QTL,表明控制叶绿素含量qCC-1效应随水稻叶片的衰老而降低。     

玉米子粒中锌及铁铜锰含量的遗传及QTL分析

分别利用三交组合DH8×登海40和DH86×沈137创建F1代DH群体A和群体B,比较2个不同遗传背景下DH群体子粒中锌及铁铜锰含量的变化,并对2个供试群体2年间的试验结果进行了QTL分析。发现玉米子粒中锌及铁铜锰的含量在不同个体间、不同年份间受环境影响比较大,且表现不稳定;群体内呈现连续性数量性状变化,服从于正态分布。对群体A2年子粒中锌及铁铜锰含量进行QTL定位,结果2007年检测到了5个与这些性状有关的QTL,可解释的遗传变异范围为9.41%~43.67%;2008年检测到9个QTL,可解释的遗传变异范围为11.21%~42.96%。2年间末检测到相同的QTL位点。对群体B进行QTL定位,2年间检测到18个QTL位点,分布于除第5染色体以外的其余9条染色体上。其中,2007年检测到12个QTL,2008年获得6个QTL,相同的QTL为2个,控制锌含量的1个位点位于第3染色体的p-umc1399-p-bnlg1605区段,控制铜含量的1个位点位于第2染色体的bnlg1746区段。     

水稻耐亚铁毒QTLs的定位

亚铁毒是潜育性水稻土中限制水稻产量的主要因子。利用龙杂8503／IR64的F2和等价的F3群体,在营养液中培养来定位耐亚铁毒的QTLs。通过构建101SSR标记的遗传连锁图谱来确定耐亚铁毒QTLs的位置和特性。借助叶片棕色斑点指数、株高和最大根长3个性状,利用营养液在水稻苗期来评价F2单株、F3群体和亲本龙杂8503、IR64,共检测到叶片棕色斑点指数、株高和最大根长的QTLs20个,分布在水稻的10条染色体上,表明这些性状受多基因控制。控制叶片棕色斑点指数的QTLs分别定位在第1染色体的RM315-RM212、第2染色体的RM6-RM240和第4染色体的RM252-RM451之间。与前人的研究结果比较发现：1）位于第4染色体RM252-RM451之间的控制叶片棕色斑点指数的QTL与水稻功能图谱上控制叶绿素含量减少的QTL的位置一致。另一个位于第1染色体的RM315-RM212之间的控制叶片棕色斑点指数的QTL与水稻功能图谱上位于C178-R2635之间控制叶绿素含量的QTL连锁。2）位于第2染色体RM6-RM240之间的第3个控制叶片棕色斑点指数的QTL与位于RZ58-CD0686的控制钾吸收的QTL连锁。     

Analysis of allele segregation distortion in a swine resource family

Segregation distortion of alleles was found in several regions of the genome in allele type analyses of genetic markers for a swine resource family that had been constructed by crossing G?ttingen miniature pig and Meishan breeds. From these regions, a region on chromosome 6 presented a distortion over several consecutive markers. This chromosome 6 region was subsequently further investigated to reveal that alleles of a chromosome 6 homologue of the Gottingen miniature pig were not found in a homozygous family member. The litter size of F1-crosses which were able to produce homozygotes in this region were 24% smaller, on average, than F1-crosses which were unable to produce homozygotes. This indicated that this region of the chromosome 6 homologue contained a recessive gene or genes which could terminate fetal development. An additional 10 markers were subsequently used to investigate the region more precisely. These studies revealed that this region spans 7 cM and is located between markers Sw855 and Sw122. Since current comparative maps show that this region corresponds to the human chromosome 19 q-arm, genes positioned on the human chromosome 19 q-arm were screened to select 20 candidate genes. These included the pregnancy-specific beta-1-glycoprotein gene.     

Quantitative trait loci for carcass traits on pig chromosomes 4, 6, 7, 8 and 13

For 22 carcass traits, we identified 16 QTLs (based on data for pig resource population no. 214, including 180 F2 hybrids of 3 Yorkshire boars and 8 Meishan sows) and mapped them with the use of 39 microsatellite marker loci on chromosomes 4, 6, 7, 8 and 13. Five QTLs were highly significant (P < or = 0.01 at chromosome level): for skin weight (on chromosome 7 at SW1856 and on chromosome 13 at SW1495), skin percentage (on chromosome 7 between SW2155 and SW1856 and on chromosome 13 between SW1495 and SW520), and ratio of leg and butt to carcass (on chromosome 4 at SW1996). The remaining 11 QTLs were significant (P < or = 0.05 at chromosome level): for backfat thickness at shoulder, loin eye width, loin eye height, fat meat weight, lean meat weight, skin weight, bone weight, skin percentage, fat meat percentage, and ratio of lean meat to fat meat. The proportion of phenotypic variance explained by these QTLs ranged from 0.06% (QTL for loin eye width on chromosome 8 between SW1037 and SW1953) to 18.04% (QTL for ratio of lean meat to fat meat on chromosome 7 between SW252 and SW581). Seven of the QTLs reported here are novel.     

猪重要胴体性状的遗传定位

为了寻找影响猪重要胴体性状主基因在染色体的位置,我们以大白猪和梅山猪为父母本建立了F2资源家系。随机选留81头F2代个体,经屠宰获得猪胴体性状数据。结合家系个体的48个微卫星标记基因型,用线性模型最小二乘法对各胴体性状进行数量性状基因座（QTL）的区间定位。定位结果表明位于猪染色体（SSC）4号的瘦肉率和瘦肉量QTL达到基因组极显著水平;SSC1、2和4上眼肌面积QTL达到染色体显著水平;位于SSC1和4上的眼肌高度QTL与眼肌面积QTL在同一染色体区域;而眼肌宽度QTL位于SSC6;位于SSC7同一标记区间的皮重、皮率、骨重和骨率QTL表现出很好的一致性,均达到染色体显著水平。SSC6和7的体长QTL达到染色体显著水平。 Abstract: To detect quantitative trait loci (QTL) for body composition traits in pigs, a resource family with three-generation was developed by using Large White grand sires and Meishan grand dams. A total of 81 F2 progenies were phenotyped for body composition. All animals were genotyped for microsatellite markers. The main results are as follows:, the strongest linkages at genome-wise level of lean meat percentage and total meat content were detected on SSC1 and 4. QTLs for loin eye area were located on SSC1, 2 and 4, QTLs for loin eye height on SSC 1 and 4, and QTLs for loin eye width on SSC 6. The best positions estimated for QTLs of skin percentage and of skin weight were in the same marker interval. Two QTLs significant at genome-wise level or highly significant at chromosome-wide level for carcass length were located on SSC6 and 7.     

Identification of quantitative trait loci associated with small brown planthopper (Laodelphax striatellus Fallén) resistance in rice (Oryza sativa L.)

F(2) and BC(1) populations derived from the cross between 02428 / Rathu Heenati were used to investigate small brown planthopper (SBPH) resistance. Using the F(2) population, three QTLs for antixenosis against SBPH were located on chromosomes 2, 5 and 6, and accounted for 30.75% of the phenotypic variance; three QTLs for antibiosis against SBPH were detected on chromosomes 8, 9 and 12. qSBPH5-c explaining 7.21% of phenotypic variance for antibiosis was identified on chromosome 5 using the BC(1) population. A major QTL, qSBPH12-a1, explained about 40% of the phenotypic variance, and a minor QTL, qSBPH4-a, was detected by the SSST method in both the F(2) and BC(1) populations. The QTLs indentified in the present study will be useful for marker assisted selection of SBPH resistance in rice.     

QTLs for grain dry milling properties, composition and vitreousness in maize recombinant inbred lines

Vitreousness and kernel hardness are important properties for maize processing and end-product quality. In order to examine the genetic basis of these traits, a recombinant inbred line population resulting from a cross between a flint line (F-2) and a semident line (Io) was used to search for vitreousness and kernel composition QTLs. Vitreousness was measured by image processing from a kernel section, while NIR spectroscopy was used to estimate starch, protein, cellulose, lipid and semolina yield. In addition, thousand-grain weight and grain weight per ear were measured. The MQTL method was used to map the QTLs for the different traits. An additional program allowed for the detection of interaction QTLs between markers. The total number of main-effect and interaction QTLs was similar. The QTLs were not evenly distributed but tended to cluster. Such clusters, mixing main-effect and interaction QTLs, were observed at six positions : on chromosomes 1, 2, 3, 6, 8 and 9. Two of them, on chromosomes 6 and 9, concerned both QTLs for kernel-weight traits and QTLs for kernel-composition traits (protein and cellulose). Technological-trait QTLs (vitreousness or semolina yield) were located less than 16 cM from a protein-content QTL on chromosome 2, and were co-located with lipid- and starch-content QTLs on chromosome 8. The co-location of a vitreousness and a semolina-yield QTL at the telomeric end of the chromosome 2 (Bin 2.02) is likely to be meaningful since measurement of these related traits, made by completely different methods (NIRS vs image processing), yielded very close QTLs. A similar location was previously reported independently for a kernel-friability QTL. Comparing the map location of the numerous loci for known-function genes it was shown that three zein loci were closely linked to QTLs for vitreousness on chromosome 3, for semolina yield and starch on chromosome 4, and for protein, cellulose and grain weight on chromosome 9. Some other candidate genes linked to starch precursor metabolism were also suggested on chromosomes 6 and 8. Received: 27 April 2000 / Accepted: 3 July 2000     

Identification of quantitative trait loci for the dead leaf rate and the seedling dead rate under alkaline stress in rice

The quantitative trait loci (QTLs) for the dead leaf rate (DLR) and the dead seedling rate (DSR) at the different rice growing periods after transplanting under alkaline stress were identified using an F2:3 population, which included 200 individuals and lines derived from a cross betweea two japonica rice cultivars Gaochan 106 and Changbai 9 with microsatellite markers. The DLR detected at 20 days to 62 days after transplanting under alkaline stress showed continuous normal or near normal distributions in F3 lines, which was the quantita-tive trait controlled by multiple genes. The DSR showed a continuous distribution with 3 or 4 peaks and was the quantitative trait con-trolled by main and multiple genes when rice was grown for 62 days after transplanting under alkaline stress. Thirteen QTLs associated with DLR were detected at 20 days to 62 days after transplanting under alkaline stress. Among these, qDLR9-2 located in RM5786-RMI60 on chromosome 9 was detected at 34 days, 41 days, 48 days, 55 days, and 62 days, respectively; qDLR4 located in RM3524-RM3866 on chromosome 4 was detected at 34 days, 41 days, and 48 days, respectively; qDLR7-1 located in RM3859-RM320 on chromosome 7 was detected at 20 days and 27 days; and qDLR6-2 in RM1340-RM5957 on chromosome 6 was detected at 55 days and 62 days, respectively. The alleles of both qDLR9-2 and qDLR4 were derived from alkaline sensitive parent "Gaochan 106". The alleles of both qDLR7-1 and qDLR6-2 were from alkaline tolerant parent Changbai 9. These geue actions showed dominance and over dominance primarily. Six QTLs associated with DSR were detected at 62 days after transplanting under alkaline stress. Among these, qDSR6-2 and qDSR8 were located in RM1340-RM5957 on chromosome 6 and in RM3752-RM404 on chromosome 8, respectively, which were asso-ciated with DSR and accounted for 20.32% and 18.86% of the observed phenotypic variation, respectively; qDSR11-2 and qDSR11-3 were located in RM536-RM479 and RM2596-RM286 on chromosome 11, respectively, which were associated with DSR explaining 25.85% and 15.41% of the observed phenotypic variation, respectively. The marker flanking distances of these QTLs were quite far ex-cept that of qDSR6-2, which should be researched further.     

水稻米粒延伸性的遗传剖析

以籼稻ZYQ8与粳稻JX17为亲本的DH群体作为研究材料,考察DH群体及双亲的米粒延伸率相关性状,并使用该群体的分子连锁图谱进行QTL分析.共检测到14个与稻米延伸性有关的QTL,包括2个粒长QTL、7个饭粒长QTL和5个米粒延伸率QTL,分别位于第1、2、3、5、6、7、10、11和12染色体.所有QTL的LOD值介于2.26～9.25,分别解释性状变异的5.31%～17.21%.在第3染色体上的G249～G164、第6染色体上的G30～RZ516和第10染色体上的G1082～GA223区间同时检测到控制饭粒长和米粒延伸率的QTL.米粒延伸性受多基因控制,Wx基因与位于第6染色体上的qCRE-6的G30～RZ516区间相近,对米饭的延伸性具重要影响.     

QTLs for resistance to preharvest sprouting in rye (<Emphasis Type="Italic">Secale cereale</Emphasis> L.)

Grain quality of rye is often negatively affected by sprouting - a complex trait with a poorly understood genetic background and strong interaction with weather conditions. The aim of this report was to detect the main quantitative trait loci (QTLs) underlying preharvest sprouting resistance in rye, measured as a percentage of sprouted kernels after spraying spikes with water for 7 days. Simple and composite interval mapping, carried out in 3 environments on 94 F3 and F4 families of the cross between sprouting-susceptible (541) and sprouting-resistant (Ot1-3) inbred lines, revealed 5 QTLs located on chromosome arms 1RL, 2RL, 5RL, 6RL and 7RL. The significance of these QTLs was additionally proved by disruptive selection carried out on 5000 F2 plants of the 541 x Ot1-3 cross and continued to the F5 generation of recombinant inbred lines (RIL), which strongly affected allele frequencies at linked marker loci. Resistance to preharvest sprouting showed dominant inheritance except for QPhs.uas-7R.1 (recessive) and QPhs.uas-1R.1 (additive). Results of the present study suggest that introgression of 4-5 QTLs, identified in line Ot1-3, should substantially reduce sprouting risk in rye varieties.