水稻6个异交相关性状的SSR关联分析

从水稻核心种质和栽培品种中选取95个品种构成品种总群体,调查该群体6个异交相关性状。选用分布在水稻12条染色体上的93个SSR标记对这95个品种进行基因型鉴定。采用TASSEL软件中一般线性模型对标记与性状间的关联进行分析,发掘有利等位变异和相应载体品种。结果表明:品种总群体中6个异交性状的变异系数为9.9%～62.9%。共检测到22个与异交性状相关联的SSR分子标记,其中8个与剑叶角度相关联,2个与花丝长度相关联,4个与花药长度相关联,1个与柱头长度相关联,3个与柱头外露率相关联,9个与开颖角度相关联。发掘了一批携有优良等位变异且效应值较大的载体品种。携有RM480-197 bp和RM535-170 bp条带的‘无芒早稻’分别对增加剑叶角度和花丝长度效应最大。携有RM311-162bp条带的‘敲冰黄’对增加花药长度效应最大。携有RM498-187 bp条带的‘滇屯502选早’对增加柱头长度效应最大。携有RM206-150 bp条带的‘徐稻5号’对提高柱头外露率效应最大。携有RM311-159 bp条带的‘小白野稻’对增加开颖角度效应最大。这些有利等位变异及其载体品种可用作水稻异交性状遗传改良的亲本。     

籼粳稻F1花粉不育性等位基因的基因型和分化度

以台中６５及其等基因Ｆ１不育系为遗传传测验种，测定了栽培稻４个籼型品种１０个粳型品种在Ｓ－Ｅ２和Ｓ－Ｅ５基因座上的Ｆ１花粉不育基因型和分化度，结果表明，在这两个基因在座上，籼型品种和粳型品种分别带有高频率，高分化度的Ｓ和Ｓ基因。试验结果支持了单基因座子体－配子体互作模式对杂种不育性的解释，并为栽培稻籼粳亚种的分类提供了新依据。     

Selection based on progeny testing induces rapid changes in myostatin allele frequencies - a case study in sheep

In this study we show that selection based on progeny testing is able to induce a rapid change in allele frequency, even when a fairly broad and balanced breeding goal is applied. The myostatin 3'-UTR mutation (c.*1232G>A) previously found to affect muscularity in Texel sheep is also present in the Norwegian White Sheep population. By genotyping the rams used for artificial insemination (born in1977-2006), a rapid increase in the c.*1232G>A allele frequency was observed, from 0.31 in 1990 to 0.82 in 2006. The major increase was observed after BLUP-based breeding values and the EUROP classification system for carcass quality was implemented in 1991 and 1996, respectively. The MSTN frameshift mutation c.960delG, recently identified in this population, did not show a similar increase in allele frequency during the same period, in spite that it has a strong desirable effect on meat and fat traits. The results also illustrate that unwanted side effects can rapidly be introduced into a population using an efficient breeding scheme. A system for monitoring changes in phenotypic traits additional to those under selection is therefore recommended to identify possible side effects at an early stage.     

F2 screening for resistance to pyramided Bacillus thuringiensis maize in Louisiana and Mississippi populations of Diatraea saccharalis (Lepidoptera: Crambidae)

BACKGROUND: In the mid‐southern region of the United States, sugarcane borer, Diatraea saccharalis (F.), is a major target pest of transgenic maize expressing Bacillus thuringiensis (Bt) proteins. Novel transgenic maize technologies containing two or more pyramided Bt genes for controlling lepidopteran pests have recently become commercially available. Insect resistance management (IRM) is an important issue in the sustainable use of Bt crop technologies. The objective of this study was to determine the frequency of resistance alleles in field populations of D. saccharalis to the new pyramided Bt maize technologies. RESULTS: A total of 382 F₂ family lines derived from 735 feral larvae/pupae of D. saccharalis collected from six locations in Louisiana and Mississippi during 2008 and 2009 were screened for resistance to three new Bt maize technologies: MON 89034, Genuity? VT Triple Pro? and SmartStax?. None of the 382 F₂ isoline families survived on the Bt maize leaf tissue for ≥ 12 days in the F₂ screen. The joint frequency for two‐ or three‐gene resistance models with 95% probability in these populations was estimated to be < 0.0063 to MON 89034 and < 0.003 to VT Triple Pro? and SmartStax?. CONCLUSION: These results suggest that the resistance allele frequency in D. saccharalis to the three pyramided Bt maize technologies is low in the mid‐southern region of the United States, which should meet the rare resistance assumption of the currently used IRM strategy for Bt maize. Copyright © 2011 Society of Chemical Industry     

Effect of allele frequencies,effect sizes and number of markers on prediction of quantitative traits in chickens

The objective was to assess goodness of fit and predictive ability of subsets of single nucleotide polymorphism (SNP) markers constructed based on minor allele frequency (MAF), effect sizes and varying marker density. Target traits were body weight (BW), ultrasound measurement of breast muscle (BM) and hen house egg production (HHP) in broiler chickens. We used a 600 K Affymetrix platform with 1352 birds genotyped. The prediction method was genomic best linear unbiased prediction (GBLUP) with 354 564 single nucleotide polymorphisms (SNPs) used to derive a genomic relationship matrix ( G ). Predictive ability was assessed as the correlation between predicted genomic values and corrected phenotypes from a threefold cross‐validation. Predictive ability was 0.27 ± 0.002 for BW, 0.33 ± 0.001 for BM and 0.20 ± 0.002 for HHP. For the three traits studied, predictive ability decreased when SNPs with a higher MAF were used to construct G . Selection of the 20% SNPs with the largest absolute effect sizes induced a predictive ability equal to that from fitting all markers together. When density of markers increased from 5 K to 20 K, predictive ability enhanced slightly. These results provide evidence that designing a low‐density chip using low‐frequency markers with large effect sizes may be useful for commercial usage.     

Protein polymorphism and genetic variation in the catfish Synodontis schall (Bloch-Schneider, 1801) and S. serratus (Ruppel, 1829) from the White Nile (Sudan)

Protein polymorphism and allelic variation were investigated in the blood of the catfish, Synodontis schall (Bloch‐Schneider, 1801) and S. serratus (Ruppel, 1829) from three localities along the White Nile. The first sampling locality at khartoum, the second at Jebel Aulia Dam, 45 km south of khartoum and the third locality was 45 km southward along the White Nile. Seventeen gene loci were identified in separating 13 enzymes and proteins. Nine loci were polymorphic and eight were monomorphic in the two species. Two alleles were observed for each polymorphic locus. Except for serum albumin (ALB^*) and erythrocyte glucose phosphate isomerase (GPI‐1^*), all corresponding allozymes in the two species revealed similar mobilities and separation patterns. Serum albumin (ALB^*) was monomorphic with a molecular weight of 67 kd in S. schall and 60–62 kd in S. serratus. Glucose phosphate isomerase (GPI‐1^*) was polymorphic in S. schall, but monomorphic in S. serratus. A contingency (χ²) test shows significant interspecies heterogeneity in allele frequency at (haemoglobin (HB^*)), (6‐phosphogluconate dehydrogenase (6PGD^*)) and (superoxide dismutase (SOD^*)) but none of the other polymorphic loci. Average heterozygosity was (0.26) for both species and the genetic distance between the two species was (0.22).     

西藏小麦醇溶蛋白Gli-1和Gli-2位点等位基因组成分析

利用A -PAGE方法 ,鉴定了 130份西藏小麦地方品种的Gli- 1和Gli - 2位点等位基因组成。结果表明 ,西藏小麦的 6个主要醇溶蛋白位点等位基因组成类型丰富。共出现了 98个等位基因 ,114种组合。各位点平均Nei氏遗传变异系数高达 0 85 4。在各位点基因中 ,Nei氏遗传变异系数在第一和第六同源群的相应位点表现相同趋势 ,以A组最高 ,B组次之 ,D组最低。 6个主要醇溶蛋白位点的等位变异 7～ 2 4个 ,平均 16 33个。出现频率最高的分别是Gli-A1urt3(14 6 2 % )、Gli -B1k(15 38% )、Gli -D1a(4 0 0 0 % )、Gli-A2o(14 6 2 % )、Gli-B2a(2 2 38% )和Gli-D2a(4 0 0 0 % )。在Gli-A1、Gli-B1和Gli-A2位点上分别出现了 4种、2种和 2种前人未报道的遗传块。在Gli-B1位点 ,有 3份材料未表达。     

单核苷酸突变的检测及其在畜牧业中的应用前景

单核苷酸多态性 ( SNP)是最新发展起来的第 3代分子标记 ,具有密度高、双等位基因、易实现自动化检测的特点。本文重点介绍了 SNP检测的方法和原理及其在畜牧业研究生产中的广泛利用前景。并提出 SNP研究中遇到的一些问题     

Developing rice lines possessing neutral alleles at sterility loci to improve the width of compatibility

To improve the width of compatibility for overcoming various sterilities in inter‐subspecific hybrid rice, some elite lines combining several sterility‐neutral genes were developed and the effects on mitigating various hybrid sterilities were tested. From Akihikari// IR36/Dular, neutral genes at ga11 and six sterility loci, S5, S7, S8, S9, S15 and S16, were combined and elite lines were obtained in their successive progeny. Four of the lines tested were confirmed to combine the neutral alleles S5‐n, S7‐n, S8‐n, S9‐n, S15‐n and S16‐n at the sterility loci and, among them, two harboured an additional gamete abortion‐neutral allele, ga11‐n. F₁s, which used the lines and various testers as parents, mitigated the spikelet sterilities by six sterility loci and gamete abortion by a gametophyte gene, ga11. These lines could be selectively used as parents or donors to increase the width of compatibility of rice varieties for improving fertility in inter‐subspecific hybrid rice breeding.