番茄抗病基因Tm-22及其等位基因氨基酸序列的比较

 从4个番茄栽培品种（Lycopersicon esculentum Miller）中获得了Tm-2²等位基因的同源克隆，进行序列分析，结果表明：'沙龙'、'渝抗2号'和'97-4'分别与'GCR-267'（Tm-2²）、'GCR-236'(tm-2)、以及'GCR-26'(tm-2)有100％的同源性, 而樱桃番茄（Lycopersicon peruvianum. var.cerasiforme）品种'樱红1号'与'GCR-26'（tm-2）仅有98％的同源性；在C-端的LRR结构域中，抗病基因 Tm-2²和Tm-2 编码蛋白的氨基酸序列与感病基因tm-2存在624和704两个位点的氨基酸差异，即624位点的脯氨酸（P）对应亮氨酸（L）、704位点的甲硫氨酸（M）对应异亮氨酸（I）； 在601-790个氨基酸的LRR结构域中，抗病基因Tm-2²、Tm-2及其秘鲁种（Lycopersicon peruvianum var. dentatum）lptm-2三者均与感病基因tm-2的编码蛋白存在23个氨基酸的差异；（4）樱桃番茄品种'樱红1号'与含有tm-2基因的栽培种之间具有同源性关系。     

平衡群体中半同胞对子间的亲属关系研究

利用群体遗传学的基本知识推导出1对等位基因平衡群体中半同胞对子间基因型的联合概率分布;给出了半同胞对子间的联合信息熵、互信息,并定义了信息关联系数;与生物统计学研究相比,表明生物信息学的方法可使1对等位基因平衡群体中半同胞对子间的亲属关系研究成为可能。     

Altered tissue-specific expression at the Wx gene of the opaque mutants in rice

Amylose content is a major determinant of the eating quality in rice. To elucidate the allelic diversity at the Waxy (Wx) gene which controls the amylose synthesis, two cultivated strains having opaque endosperms were studied. The gene responsible for opaque endosperms was introduced into the genetic background of the Japonica type of rice by successive backcrosses, and the two near-isogenic lines (NILs) were selected from the B5 generation. The genetic experiments revealed that an allele, Wx^op, controls opaque endosperms which show chalky as wx endosperms in spite of the production of amylose. Immunoblotting analysis was carried out to compare the gene expression by using the NILs with 4 different alleles (Wx^a, Wx^b, Wx^op and wx). The level of the gene product bound to starch granules was slightly lower in the NILs with Wx^op than that with Wx^b, showing a positive correlation with amylose content in the endosperm. Extracts from mature anthers indicated that the gene product was markedly reduced in the NILs with Wx^op as well as that with wx, showing an altered expression in the tissue specificity in the Wxop lines. Sequence analysis suggested that the Wx^op had been derived from Wx^a, independently of the origin of Wx^b. The importance of the gene regulation was discussed in relation to diversified phenotypes established during the domestication process.     

Subspecies Characterization of Porcine Campylobacter coli and Campylobacter jejuni by Multilocus Enzyme Electrophoresis typing

Enteropathogenic Campylobacter jejuni, C. coli and C. lari are currently the most common causes of acute infectious diarrhoeal illness in the UK. Many domestic animals, including pigs, act as natural reservoirs of these organisms and infection may occur through the ingestion of contaminated foodstuffs. C. jejuni and C. coli, isolated from the livers of bacon pigs, were examined at subspecies level by multilocus enzyme electrophoresis (MEE) typing with seven enzymic loci. Polymorphological variation was highest with indophenol oxidase, isocitrate dehydrogenase and L-phenylalanyl-L-leucine peptidase giving 5, 5 and 4 alleles at these loci, respectively. The 35 Campylobacter isolates examined in this study (12 C. jejuni and 23 C. coli) represented 30 unique electrophoretic types (ETs). Of these ETs, 8 unique types were detected for the 12 C. jejuni isolates and 19 unique ETs were detected for the 23 C. coli isolates. In addition, 3 types (ETs 2, 5, 10) were shared in common among C. jejuni and C. coli. The average number of alleles per enzyme locus was 3.28. The mean genetic diversity, i.e. arithmetic average over all loci assayed, including monomorphic values, was 0.5573 and 0.5350 for C. jejuni and C. coli, respectively. Alleles were shared by C. jejuni and C. coli, suggesting an exchange of genetic material between the species. MEE analyses of isolates showed that there was a wide range of subspecies types within both C. jejuni and C. coli in porcine livers. In certain cases, up to four phenotypically different strains of C. coli were isolated from one liver, indicating multiple infections.     

A microsatellite marker tool for parentage analysis in Senegal sole (Solea senegalensis): Genotyping errors, null alleles and conformance to theoretical assumptions

A set of 50 potential microsatellite loci previously described in several flatfish species was evaluated for designing a suitable tool for parentage assessment in Senegal sole (Solea senegalensis). Low cross-amplification within Pleuronectiformes, even between congeneric species, was achieved. This suggests a low conservation of microsatellite flanking regions in this order regarding other fish orders of similar evolutionary age. Twelve loci showed appropriate amplification and polymorphism to acquire enough statistical power for parentage analysis. All forty-one individuals from one broodstock and 320 offspring were analyzed using this set of markers. The high potential of microsatellites for parentage exclusion (Excl1 = 0.9999; Excl2 = 1) permitted us to trace back all offspring to single pairs of parents. The families obtained were used to analyze the performances of the loci applied and to identify possible sources of error for parentage analysis in Senegal sole. The 2.5% of single mismatches in the families studied were attributed mostly to genotyping errors and to a lesser extent to null alleles. The average mutation rate estimated over 7680 gametes was in the range reported within fish (3.9 × 10^− 4) and did not compromise parentage analysis. All loci conformed to theoretical assumptions (Mendelian segregation, independent segregation), excluding the F13-II8/4/7 and Sol 9A loci, which showed strong genotypic association in the families analyzed. A set of 4 microsatellites (Sol CA13, F13-II8/4/7, Smax-02 and Sse GATA38) was finally selected for parentage evaluation in S. senegalensis combining both enough exclusion potential (> 0.970) and the lowest economic cost.     

Milling and Chinese raw white noodle qualities of common wheat near-isogenic lines differing in puroindoline b alleles

Understanding the effects of different alleles at the puroindoline b (Pinb) locus on processing quality will provide crucial information for quality improvement. Seven near-isogenic lines (NILs) planted at two locations in the 2008 cropping season were used to determine the effect of puroindoline b alleles on milling performance and Chinese raw white noodle (CRWN) quality. The Pina-D1b/Pinb-D1a genotype possessed significantly higher values in grain hardness, protein content and starch damage than other genotypes, whereas the Pina-D1a/Pinb-D1d genotype had the lowest grain hardness and starch damage, with higher break flour yield, and less reduction flour yield, higher flour colour L*, and lower flour colour b*, than other genotypes. Farinograph parameters, except for water absorption, were not significantly affected by variation of puroindoline b alleles. Pina-D1a/Pinb-D1e had the highest peak viscosity, whereas the lowest value was observed in a Pina-D1b/Pinb-D1a genotype. For CRWN quality, higher noodle viscoelasticity was obtained in the genotype Pina-D1a/Pinb-D1e and Pina-D1a/Pinb-D1g, whereas Pina-D1a/Pinb-D1d had a lower smoothness score. Genotypes with Pina-D1a/Pinb-D1e and Pina-D1a/Pinb-D1g produced the best total noodle score. It was concluded that genotype Pina-D1a/Pinb-D1d had better milling qualities, whereas Pina-D1a/Pinb-D1e and Pina-D1a/Pinb-D1g had slightly superior CRWN qualities in comparison with other genotypes.     

长江中下游麦区小麦品种籽粒硬度及puroindoline基因等位变异的分子检测

为了明确长江中下游麦区小麦籽粒硬度及puroindoline基因型的分布,以该麦区105份小麦育成品种为材料,利用单籽粒硬度仪(SKCS)测定其籽粒硬度,利用分子标记检测和基因序列分析鉴定puroindoline基因的等位变异。结果表明,在长江中下游麦区历年育成的小麦品种中软质麦比例较高,占52.4%,硬质麦和混合麦分别占38.1%和9.5%;硬质麦和混合麦中存在Pinb-D1b、Pina-D1b和Pinb-D1p三种变异类型,突变频率分别为29.5%、10.5%和3.8%。     

近交及其对水产养殖的影响

因大多数野生物种的捕捞已接近甚至超过了可开发的限度,因此必须大量增加水产品的养殖以满足人们对水产品的需要。目前,许多水产养殖种类的苗种来源于野生亲体或野生种苗,但是当野生种群被过度捕捞或数量大量减少时,越来越多的苗种将来源于人工蓄养的亲体群体。     

微卫星标记BM3413和OB2在5个绵羊群体中多态性的研究

选用萨福克、德国美利奴、特克塞尔、乌珠穆沁、以及右玉本地绵羊5个绵羊群体共250个个体,通过耳组织提取基因组DNA,用2对微卫星引物进行PCR扩增,通过电泳分型、凝胶成像系统分析各位点等位基因及全部个体的标记基因型,计算基因频率、多态信息含量(PIC)和杂合度等,从分子水平上分析5个绵羊品种的遗传多态性。结果表明,BM3413和OB2这2个位点的等位基因数分别为7和8,多态信息含量PIC﹥0.5,杂合度为0.8271～0.8467,均属于高度多态性位点,用于作为与生产性能相关的遗传标记是较理想的。