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1.
为探讨RAPD标记在家鸡杂种优势预测中的应用价值, 分析了力康白壳蛋鸡纯系的RAPD变异及其与杂种优势的关系。5个纯系内和系间显示出低水平的变异。根据品系间遗传距离DS用UPGMA法进行聚类分析,品系a、e、d聚为一类, 而h、l聚为另一类。简单线性相关分析表明,父系相似系数与F1代的60周龄产蛋数存在正相关而与蛋重的杂种优势率存在负相关;母系相似系数与产蛋数的杂种优势率存在高度负相关。但品系间遗传距离与各性状及其杂种优势率之间没有显著的相关关系。 Abstract To assess the value of RAPD markers for the prediction of heterosis in chicken, analyses of data from a crossbreeding experiment and RAPD assays of 5 Leghorn white shell lines (a, d, e, h, l) were conducted. The RAPD showed a low level of variability within and among 5 lines. The dendrogram was constructed by UPGMA based on inter-line genetic distance (DS), which indicted that 5 lines were clustered into two groups: one consisting of line a, e, d, and the other line h, l. The above results were consistent with the pedigree information of the pure lines. By using linear correlation, it was shown that similarity coeffcient within paternal line was positively correlated with 60-week egg number and negatively correlated with the heterosis for egg weight, and that similarity index within maternal line was highly negatively correlated with the heterosis for egg number. However, no significant correlations between genetic distance and traits or their heterosis were found.  相似文献   

2.
多个SPF鸡品系的RAPD分析   总被引:3,自引:0,他引:3  
目的用RAPD方法分析三个品系SPF鸡的遗传变异,以指导SPF鸡群的育种工作.方法对三个SPF鸡品系F、M及B系和对照H纯系分别采血样30个,等量混匀为三个混合样,提取DNA,筛选随机引物,优化反应体系后进行PCR扩增,计算品系内平均相似系数,根据品系间遗传距离进行聚类分析并绘制树状聚类图.结果60个随机引物中有13个产生清晰稳定的多态条带,B系品系内平均相似系数为0.903,F系和M系分别为0.673和0.755,H系为0.968;聚类分析的结果是每个品系的三个样品先聚为一类,然后F系与M系、B系与对照H系分别聚为一类.结论F系和M系的纯合程度均较低,而B系较高;F系与M系的遗传距离较近,而与B系之间距离较远,三者亲缘关系以F系与M系较近,这与各个品系的引种背景相一致.  相似文献   

3.
利用微卫星标记分析蛋鸡配套系的遗传关系   总被引:4,自引:0,他引:4  
李显耀  曲鲁江  杨宁 《遗传学报》2004,31(12):1351-1355
选用20个微卫星标记分析了2001年和2002年引进的H高产蛋鸡配套系祖代各品系之间的遗传关系,计算杂合度、多态信息含量(PIC)、有效等位基因数、Nei氏遗传距离等统计量,分析了品系内和品系间的遗传变异,并采用非加权类平均法(UPGMA)对各品系进行聚类。结果显示:每个微卫星位点的平均等位基因数为3.250,平均有效等位基因数为2.395,20个微卫星标记共有等位基因65个,各位点的PIC在0.102—0.729之间变动,平均为0.454;各位点杂合度的变动范围是0.108—0.765,各品系杂合度的分布范围是从A2001的0.390到D2001的0.452之间,各品系的杂合度较低,群体内变异较小。配套系各品系是经过高度选育的,所以群体内变异较小,本研究结果与育种实际相符合,也从另一方面说明了品系的遗传特征能够由各微卫星位点的多态性得到真实的反映。A、B两系之间的遗传距离为0.005—0.016,遗传相似系数大于0.984;C、D两系之间的遗传距离为0.094~0.119,遗传相似系数为0.900左右。这些结果表明,A、B应为同一个品系或遗传关系非常近的两个品系,C、D是两个遗传关系较远的品系。  相似文献   

4.
用RAPD技术分析了18个三色堇(Viola wittrockiana)自交系的遗传多样性。21个随机引物扩增了167条带,其中127条具多态性,显示自交系间存在较大的遗传变异。用UPGMA法可将自交系聚为五大类,其分类结果与花径和材料来源地基本一致。以其中的5个自交系进行双列杂交试验,研究了RAPD遗传距离与三色堇杂交后代10个性状杂种优势的关系,实验结果表明:RAPD遗传距离仅与花数达到0.1的显著水平,而与其它8个性状杂种优势的相关性不显著;用RPAD遗传距离预测三色堇的花数杂种优势具有一定的可靠性,但用于对其它性状杂种优势的预测目前是不可行的。  相似文献   

5.
摘要:利用SSR和SRAP两种分子标记研究了71份实验材料的遗传差异及其亲缘关系。结果表明:(1) 29对SSR标记共扩增出121条清晰地带,多态性位点分别占总扩增位点的97.5%,而27对SRAP引物扩增出175条清晰地带,多态性比率为70.3%。(2)两种标记混合聚类结果表明,在相似系数0.566处所有材料可以分为A、B两个大类群。B类在相似系数0.620处又可分为六个亚类,10个天然双低早熟甘蓝型品系、两个甘蓝型亲本和四个新型品系聚在第Ⅰ亚类中,其余的51个新型甘蓝型油菜品系分别聚在其他五个亚类中。(3)对55份新型品系进行遗传成分分析,结果表明,每个品系都含有四种带型,不同品系中不同带型所占总带数的比率不同;对新型甘蓝型品系中含有白菜型亲本特有的带所占比率分别与其和对应的甘蓝型和白菜型亲本之间的遗传距离进行相关分析,结果表明新型甘蓝型品系中白菜型亲本特有的带所占比率与其和白菜型亲本之间的遗传距离为负相关(-0.52),达到极显著水平;与其和甘蓝型亲本间的遗传距离为正相关(0.31),达到显著水平。(4)对实验材料之间的遗传距离及其来源进行分析(除与两个白菜型亲本间),遗传距离排前20位的都来自新型品系之间或天然品系与新型之间,且最大的达到0.544。  相似文献   

6.
青藏高原早熟甘蓝型春油菜遗传资源研究   总被引:1,自引:0,他引:1       下载免费PDF全文
利用SSR和SRAP 2种分子标记研究了69份试验材料的遗传差异及其亲缘关系.29对SSR标记共扩增出118条多态性带,多态性位点占总扩增位点的97.5%,27对SRAP引物扩增出123条多态性带,多态性比率为70.3%.两种标记聚类结果表明.在相似系数0.566处所有材料可以分为A、B 2个大类群;B类在相似系数0.620处又可分为7个亚类,10个天然双低早熟甘蓝型品系、2个甘蓝型亲本和4个新型品系聚在第1亚类中,其余的51个新型甘蓝型油菜品系分别聚在其他6个亚类中.对55份新型品系进行遗传成分分析,结果表明,每个品系都合有4种带型,各品系所舍不同带所占比率不同.对各品系中含有白菜型亲本带所占比率分别与其对应的两亲本之间的遗传距离进行相关分析,结果表明新型甘蓝型油菜品系中白菜型亲本带所占比率与白菜型素本间的遗传距离为负相关(-0.52),且达到极显著水平;与甘蓝型亲本间的遗传距离为正相关(0.31),且达到显著水平.对试验材料之间的遗传距离及其来源进行分析(除与2个白菜型亲本间),遗传距离排名前20位的都来自新型品系之间或天然品系与新型之间,最大为0.544.  相似文献   

7.
用RAPD技术分析了18个三色堇(Viola wittrockiana)自交系的遗传多样性。21个随机引物扩增了167条带,其中127条具多态性,显示自交系间存在较大的遗传变异。用UPGMA法可将自交系聚为五大类,其分类结果与花径和材料来源地基本一致。以其中的5个自交系进行双列杂交试验,研究了RAPD遗传距离与三色堇杂交后代10个性状杂种优势的关系,实验结果表明:RAPD遗传距离仅与花数达到0.1的显著水平,而与其它8个性状杂种优势的相关性不显著;用RPAD遗传距离预测三色堇的花数杂种优势具有一定的可靠性,但用于对其它性状杂种优势的预测目前是不可行的。  相似文献   

8.
贵州省八个种群角倍蚜ISSR遗传多样性   总被引:5,自引:1,他引:4  
基于ISSR分子标记技术对采自贵州省8个种群共139个角倍蚜样本进行遗传多样性及其与环境因子的相关性分析。筛选的12条引物共扩增出多态性条带133条,没有种群特异带出现,平均每个引物扩增的多态带数为11条,Popgene软件分析显示,总群体多态性条带比率为100%,尽管不是特意选择变异高的引物。种群间遗传相似系数变异范围介于0.899~0.955,遗传距离介于0.046~0.106,说明角倍蚜不同种群之间的遗传分化不大。聚类分析显示,8个种群共形成2个大的聚类簇,各种群之间没有明显的地域性分布规律,但遗传多样性与3月温度和3月降水量呈负相关。  相似文献   

9.
内蒙古典型草原羊草种群遗传分化的RAPD分析   总被引:18,自引:3,他引:15  
运用 RAPD技术对内蒙古典型草原不同生境 8个羊草种群进行分析。采用 2 4个随机引物 (10 nt)在 8个种群中共检测到2 2 4个扩增片断 ,其中多态性片断 173个 ,总的多态位点百分率达 77.2 % ,特异性片断 2 2个 ,占 9.82 % ,平均每个引物扩增的DNA带数为 9.3 3条。利用 Nei指数和 Shannon指数估算了 8个种群的遗传多样性 ,并计算种群相似系数和遗传距离 ,运用UPGMA法进行聚类分析。结果表明 :羊草大部分的遗传变异存在于种群内 ,只有少部分的遗传变异存在于种群间 ,Nei指数和Shannon指数计算结果分别为 85.4%和 66.8% ;羊草不同种群的遗传多样性存在差异 ;8个羊草种群平均遗传距离为 0 .2 3 16,变异范围为 0 .1587~ 0 .2 70 0 ,说明 8个羊草种群间的遗传变异不大 ,即 :在较小地理范围内羊草的遗传分化程度较小 ;8个种群可聚为 3个类群 ,聚类结果显示生境相似的种群能够聚在一起 ,而地理距离最近的种群不一定归为一类 ,说明小范围内羊草种群间的遗传分化与地理距离不存在相关性 ,而与其生境间的相似度相关。影响遗传相似性的不是单一因子而是各种因子的综合作用 ,较小地理范围内羊草种群间的遗传分化主要是由环境的异质性所引起的  相似文献   

10.
在玉米单交种育种中 ,鉴定高产杂交种和具有优良特性的自交系是一个重要的问题。研究以 1 7个优良玉米自交系为亲本 ,按照双列杂交配组合 ,利用 RAPD技术分析了 1 7个自交系的多态性以及 RAPD标记与 9个重要农艺性状 (包括产量 )的关系。基于 RAPD标记计算的相似系数聚类将 1 7个自交系分为 5个类群 ,经分析与系谱亲缘关系基本一致。杂交种性状及其特殊配合力与亲本间的遗传距离是高度相关的 ,与聚类前比较 ,聚类后平均遗传距离与平均产量、平均特殊配合力的相关系数显著提高 ,类间平均产量高于类内平均产量。RAPD技术可揭示优良玉米自交系的系谱亲缘关系 ,将自交系划分成不同的类群 ,从而为选择类间自交系杂交 ,进行亲本选配和分子标记辅助育种提供一种方法。  相似文献   

11.
Genetic diversity within and among nine pure lines of Beijing White Leghorn chickens was determined by DNA fingerprinting using human ministatellite probes 33.6 and -globin 3HVR, as well as bacteriophage M13. Within lines similarity coefficients ranged from 0.497 to 0.628, significantly higher than that within a sample of white chicken from a local market. Relationships among lines were established by clustering analysis based on inter-line coefficients of difference calculated from DNA fingerprints of pooled DNA. A complete diallel crossing among the nine pure lines was conducted. By using linear correlation analysis, it was found that the maximum distance between parental lines was positively correlated with egg number, egg production, survival rate and their corresponding heterosis percentages within a pair of reciprocal crosses. Similar relationships were found where only the higher of the reciprocal crosses were used in the analysis. It was also shown that similarity coefficients within a sire line or dam line were positively correlated with 40-week egg number and its heterosis percentage and the heterosis percentage for 40-week egg production, but negatively correlated with the 40-week survival rate of the cross-bred populations.  相似文献   

12.

Background

The development of a reliable method to predict heterosis would greatly improve the efficiency of commercial crossbreeding schemes. Extending heterosis prediction from the line level to the individual sire level would take advantage of variation between sires from the same pure line, and further increase the use of heterosis in crossbreeding schemes. We aimed at deriving the theoretical expectation for heterosis due to dominance in the crossbred offspring of individual sires, and investigating how much extra variance in heterosis can be explained by predicting heterosis at the individual sire level rather than at the line level. We used 53 421 SNP (single nucleotide polymorphism) genotypes of 3427 White Leghorn sires, allele frequencies of six White Leghorn dam-lines and cage-based records on egg number and egg weight of ~210 000 crossbred hens.

Results

We derived the expected heterosis for the offspring of individual sires as the between- and within-line genome-wide heterozygosity excess in the offspring of a sire relative to the mean heterozygosity of the pure lines. Next, we predicted heterosis by regressing offspring performance on the heterozygosity excess. Predicted heterosis ranged from 7.6 to 16.7 for egg number, and from 1.1 to 2.3 grams for egg weight. Between-line differences accounted for 99.0% of the total variance in predicted heterosis, while within-line differences among sires accounted for 0.7%.

Conclusions

We show that it is possible to predict heterosis at the sire level, thus to distinguish between sires within the same pure line with offspring that show different levels of heterosis. However, based on our data, variation in genome-wide predicted heterosis between sires from the same pure line was small; most differences were observed between lines. We hypothesise that this method may work better if predictions are based on SNPs with identified dominance effects.  相似文献   

13.
Genotypes for 24 microsatellite markers, dispersed across the chicken genome, were used to predict progeny performance and heterosis for egg production (number and mass) in 'layers' (egg-type chickens). These markers were used to evaluate genetic distance between each of 39 sires sampled from two-layer male-lines; Rhode Island Red (RIR) and White egg Leghorn (Leghorn), and a DNA pool of 30 randomly sampled females from a Brown-egg female line (Silver). Each sire was analysed for egg production across months in the laying period and cumulatively in each of three subperiods; onset (2 month), mid (9 month) and late (1 month). The average Reynolds' genetic distance between Leghorn sires and the Silver female line (theta;=0.6) was significantly higher than that between RIR sires and the Silver female line (theta;=0.5). Neither performance nor heterosis values in the RIR sire's daughters were associated with genetic distance values between sires and the Silver female line. On the other hand, performance as well as heterosis values of Leghorn's daughters were positively associated with genetic distance. This association was particularly evident in the mid-subperiod. If 25% of the most genetically distant Leghorn sires from the Silver female line had been selected in a single generation on the basis of DNA markers information only, average egg production of the crossbred daughters would have been improved by about nine eggs (3%). In principle, further improvement is possible if selection to increase genetic distance between the parental lines is carried on.  相似文献   

14.
DNA polymorphism in various goose lines by RAPD-PCR   总被引:1,自引:0,他引:1  
RAPD markers often primers were used to assess the polymorphism among pooled DNA of eight goose lines. The number of bands amplified by each primer ranged from 1 to 8, within a mean of 2.86. Some bands appeared specific for the line or genetic background. RAPD technique is an effective method for generating the polymorphic DNA marker in the goose. RAPD patterns from mixed DNA samples can reflect the genetic information of populations. The present study indicated that 10 generations selected for egg production and body weight under various pressure, resulted in genetic variation among goose lines as detected by RAPD. Selection for meat traits caused greater genetic diversity than selection for egg production.  相似文献   

15.
Summary The aim of the experiment was to determine if the estimated genetic distance between two populations could be used to predict the amount of heterosis that would occur when they were crossed. Eight lines of known relatedness to each other were produced by eight generations of sib mating and sub-lining. This produced lines that varied in coefficient of coancestry from zero to 0.78. Fourteen reciprocal crosses of these lines were used to measure heterosis for larval viability and adult fecundity. Gene frequencies at six polymorphic enzyme loci were used to estimate the genetic distances between lines, which were then compared with the known degrees of coancestry. The estimated genetic differences were poorly correlated with the known coancestry coefficients (r=0.4), possibly due to the small number of loci typed. Also genetic distances were only about 1/3 of what was expected. Selection acting on blocks of genes linked to the enzyme loci probably prevented the expected increase in homozygosity. Coancestry coefficient was correlated with heterosis (r=0.44–0.71). This level of correlation implied differences in heterosis among parent lines with the same level of coancestry. This variability is expected if a small number of loci explain most of the heterosis. The average level of heterosis was less than expected after eight generations of sib mating. This is most likely due to selection opposing the increase in homozygosity caused by inbreeding. The combination of these two imperfect correlations resulted in no significant correlation between genetic distance estimated from markers and heterosis.  相似文献   

16.
Predicting heterosis and F1 performance from the parental generation could largely enhance the efficiency of breeding hybrid or synthetic cultivars. This study was undertaken to determine the relationship between parental distances estimated from phenotypic traits or molecular markers with heterosis, F1 performance and general combining ability (GCA) in Ethiopian mustard (Brassica carinata). Nine inbred lines representing seven different geographic regions of Ethiopia were crossed in half-diallel. The nine parents along with their 36 F1s were evaluated in a replicated field trail at three locations in Ethiopia. Distances among the parents were calculated from 14 phenotypic traits (Euclidean distance, ED) and 182 random amplified polymorphic DNA (RAPD) markers (Jaccard’s distances, JD), and correlated with heterosis, F1 performance and GCA sum of parents (GCAsum). The correlation between phenotypic and molecular distances was low (r=0.34, P≤0.05). Parents with low molecular distance also had low phenotypic distance, but parents with high molecular distance had either high, intermediate or low phenotypic distance. Phenotypic distance was highly significantly correlated with mid-parent heterosis (r=0.53), F1 performance (r=0.61) and GCA (r=0.79) for seed yield. Phenotypic distance was also positively correlated with (1) heterosis, F1 performance and GCA for plant height and seeds plant−1, (2) heterosis for number of pods plant−1, and (3) F1 performance for 1,000 seed weight. Molecular distance was correlated with GCAsum (r=0.36, P≤0.05) but not significantly with heterosis and F1 performance for seed yield. For each parent a mean distance was calculated by averaging the distances to the eight other parents. Likewise, mean heterosis was estimated by averaging the heterosis obtained when each parent is crossed with the other eight. For seed yield, both mean ED and JD were significantly correlated with GCA (r=0.90, P≤0.01 for ED and r=0.68, P≤0.05 for JD) and mean heterosis (r=0.79, P≤0.05 for ED and r=0.77, P≤0.05 for JD). In conclusion, parental distances estimated from phenotypic traits better predicted heterosis, F1 performance and GCA than distances estimated from RAPD markers. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.  相似文献   

17.
Summary Heterosis (over mid parent) and useful heterosis (over commercial variety H14) estimates were obtained from a line x tester analysis of crosses involving thirteen diverse female parents with two locally adapted varieties H14 (local standard) and J34. Marked heterosis was observed for seed cotton yield, boll number and halo length. The values of positive heterosis and useful heterosis for seed cotton yield ranged from 28.1 to 87.0% and 20.1 to 45.5%, respectively. The overall study of heterosis revealed that female parents PRS-72 (USSR), 5904F (USSR) and MCU-5 (Madras Cambodian Uganda Selection, Coimbatore) were among the top three females, showing considerable heterosis in crosses with H14 and J34 for seed cotton yield and fibre properties. The practical difficulties in exploiting the phenomenon of heterosis and possible experimental approaches in upland cotton are discussed.  相似文献   

18.
 To evaluate the genetic diversity of 18 maize inbred lines, and to determine the correlation between genetic distance and single-cross hybrid performance, we have used random amplified polymorphic DNA (RAPD), a PCR-based technique. Eight of these lines came from a Thai synthetic population (BR-105), and the others derived from a Brazilian composite population (BR-106). Thirty two different primers were used giving a total of 325 reproducible amplification products, 262 of them being polymorphic. Genetic divergence was determinated using Jaccard’s similarity coefficient, and a final dendrogram was constructed using an unweighted pair-group method with arithmetical averages (UPGMA). Cluster analysis divided the samples into three distinct groups (GI, GII and GIII) that were confirmed by principal-coordinate analysis. The genetic distances (GD) were correlated with important agronomic traits for single-cross hybrids and heterosis. No correlation was found when group division was not considered, but significant correlations were detected between GI×GII and GI×GIII GDs with their respective single-cross hybrid grain-yield values. Three groups were identified; that is, the BR-106 population was divided in two different groups and the BR-105 population remained mostly as one group. The results indicated that RAPD can be used as a tool for determining the extent of genetic diversity among tropical maize inbred lines, for allocating genotypes into different groups, and also to aid in the choice of the superior crosses to be made among maize inbred lines, so reducing the number of crosses required under field evaluation. Received: 24 May 1996 / Accepted: 22 November 1996  相似文献   

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