利用SSR分子标记解析遗传学三大规律

分离规律、自由组合规律和连锁规律被称为遗传学三大规律,是认识生物遗传和变异的基础。一般教学中,主要通过对分离世代性状的表型分离特性进行观察和统计分析,是一种基于表型的分析,而利用位于同一染色体和不同染色体上的微卫星(Simple sequence repeats,SSR)分子标记,在分离世代的基因型数据及PCR扩增产物带型的分析,可以从核酸水平上比较直观地解释遗传规律,提高教学效果,加深学生对遗传规律的认识。     

Regression association analysis of fruit traits with molecular markers in cherries

The use of molecular markers supports the study of genetic marker–trait association of biological and agronomic interest in diverse genetic material. In this research, association between simple sequence repeat (SSR) and random amplified polymorphic DNA (RAPD) markers with fruit traits were investigated in two collections of cherries by applying multiple regression analysis (MRA). Thirty-eight SSR alleles and 135 RAPD fragments were found associated with 14 of affecting fruit traits. Some of SSR and RAPD markers were associated with more than one fruit trait in MRA. Such an association may arise due to pleiotropic effect of the linked quantitative trait locus on different traits. For example, some SSR and RAPD markers were associated with all four traits including fruit cracking, fruit firmness, total soluble solid (TSS) and fruit shape. Also, some markers had correlations with all four characters of TSS, anthocyanin, fruit skin color and fruit flesh color, indicating a significant correlation among these traits. Therefore, it is possible to use these markers along with morphological traits in cherry breeding programs for identification of suitable parents to produce mapping populations and hybrid cultivars. Also, these results could be useful in marker-assisted breeding programs when no other genetic information is available.     

Two different molecular types of rat mitochondrial DNAs

Experiments with restriction endonucleases showed that Sprague-Dawley strain rats have two types of mitochondrial DNAs (mtDNAs), named α- and β-types, which differ in primary structure. Individual rats have only one type. Individuals of other strains, such as Wistar, Fischer, and Donryu, also all have one of these types of mtDNA. Thus irrespective of their strain, all rats can be classified into one of two groups according to the type of their mtDNA.     

三种鳖线粒体DNA细胞色素b基因序列的比较分析

对中华鳖、砂鳖和山瑞鳖线粒体DNA细胞色素b基因进行了引物设计、PCR扩增、序列测定和PCR-PFLP(Polymerase chain reaction-restriction fragment length polymorphism)分析。研究结果表明中华鳖、砂鳖与山瑞鳖线粒体DNACytb基因的序列全长相同,均为1140bp,其A、C、G、T含量相似,分别为378个(33.2%)、322个(28.2%)1、22个(10.7%)、318个(27.9%)、373个(32.7%)、324个(28.4%)、124个(10.9%)、319个(28.0%)、380个(33.3%)3、30个(28.9%)、127个(11.1%)、303个(26.7%)。同源性及序列差异率分析表明:中华鳖与砂鳖b基因序列的同源性为92.3%,中华鳖、山瑞鳖的为85.0%,砂鳖、山瑞鳖的为84.1%;中华鳖与砂鳖b基因核苷酸序列间的差异率为7.7%,中华鳖、山瑞鳖间的序列差异率为15.0%,砂鳖、山瑞鳖间的序列差异率为15.9%,而中华鳖、砂鳖、山瑞鳖各自个体间的序列差异率分别为2.37%、0.88%和0.18%,种间差异显著。用内切酶酶切分析其扩增产物,结果表明:用内切酶NdeⅠ可准确鉴别砂鳖,而用内切酶BamHⅠ则可准确鉴别山瑞鳖。内切酶NdeⅠ和BamHⅠ的联用分析,可使这三种鳖在分子水平都得到明确的鉴定。从三种鳖线粒体DNACytb基因核苷酸序列的显著差异和酶切位点的变化,可以进一步证明砂鳖是不同于中华鳖的鳖属一新种。     

Identification of co-dominant RAPD markers tightly linked to fruit skin color in apple

A simple genetic basis for the red/yellow skincolor polymorphism in apple was verified using DNA markers. Bulked segregant analysis identified one 10-base oligomer that generated different fragments in each of the bulks. After testing the primer in four populations, two fragments were found to be associated with red skin color and another two fragments associated with yellow skin color. Three of the fragments (1160, 1180, and 1230 bp) were partly sequenced and found to share high sequence homology, suggesting these were generated from the same locus. A pair of universal primers were designed to amplify the fragments. In the Rome Beauty x White Angel population, two fragments were associated with red skin color; one fragment designated as A¹ (1160 bp) was from Rome Beauty and another fragment (A², 1180 bp) was from White Angel. Progeny possessing both fragments, or either one, had red fruit. Both parents displayed an alternate fragment, a¹ (1230 bp), associated with yellowskinned fruit. In three other crosses tested, only fragment A¹ co-segregated with red skin color; two fragments, a¹ and a² (1230 bp and 1320 bp), were associated with yellow skin color. Our results are consistent with the hypothesis that the red/yellow dimorphism is controlled by a monogenic system with the presence of the red anthocyanin pigmentation being dominant. There was no indication that other modifier genes could reverse the effect of the locus (R _f ) linked to the markers. Examination of amplification products in 56 apple cultivars and advanced breeding selections demonstrated that the universal primers could be used to correctly predict fruit skin color in most cases.     

Assessment of chronological lifespan dependent molecular damages in yeast lacking mitochondrial antioxidant genes

The free radical theory of aging states that oxidative damage to biomolecules causes aging and that antioxidants neutralize free radicals and thus decelerate aging. Mitochondria produce most of the reactive oxygen species, but at the same time have many antioxidant enzymes providing protection from these oxidants. Expecting that cells without mitochondrial antioxidant genes would accumulate higher levels of oxidative damage and, therefore, will have a shorter lifespan, we analyzed oxidative damages to biomolecules in young and chronologically aged mutants lacking the mitochondrial antioxidant genes: GRX2, CCP1, SOD1, GLO4, TRR2, TRX3, CCS1, SOD2, GRX5, and PRX1. Among these mutants, ccp1Δ, trx3Δ, grx5Δ, prx1Δ, mutants were sensitive to diamide, and ccs1Δ and sod2Δ were sensitive to both diamide and menadione. Most of the mutants were less viable in stationary phase. Chronologically aged cells produced higher amount of superoxide radical and accumulated higher levels of oxidative damages. Even though our results support the findings that old cells harbor higher amount of molecular damages, no significant difference was observed between wild type and mutant cells in terms of their damage content.     

富士苹果不同冠形微气候特征与果品质量关系的研究

对富士苹果不同冠形微气候特征与果品质量之间的关系进行了研究．结果表明,两种不同冠形,其微气候特征值变化不同,差异显著．两种冠形条件下的晒阳果、叶的温度差异显著,而遮阴果、叶差异不显著．果实内含物除蛋白质外,均有显著差异．     

DNA分子标记在果树遗传育种研究中的应用

DNA分子标记是随着分子生物学技术的发展出现的一类重要的遗传标记,近年来发展非常迅速,已在果树遗传育种研究的各个方面得到广泛的应用。介绍了几种DNA分子标记技术的原理,综述了DNA分子标记在果树种质资源研究、分子遗传图谱构建、基因定位、分子辅助选择等方面的应用,并对其在果树上的应用前景和存在问题进行了评述。     

Partial molecular characterization of some kiwi fruit cultivars by RAPD markers

Molecular variability among seven cultivars of A. deliciosa var. deliciosa was investigated through RAPD markers. Thirty four decamer primers were screened generating polymorphic patterns of amplified DNA for these cultivars. Twenty one selected primers gave clear and reporducible patterns. A total of 430 bands were produced and 29.37% of them were polymorphic. The patterns distinguished between the cultivars and their analysis established an approach to classification within A. deliciosa var. deliciosa based on RAPD markers. The dendrogram clearly differentiated male from female cultivars. While abbot and allison female cultivars were closely related, bruno and abbot female cultivars showed maximum dissimilarity.     

Use of molecular markers and flow cytometry to preserve ancient Annurca apple germplasm

The old Annurca apple cultivar (Malus domestica), particularly appreciated for its peculiar flavor and crispy flesh, was studied in order to preserve its ancient germplasm. Twelve clones of Annurca were analyzed using random amplified polymorphic DNA (RAPD) and simple-sequence repeat (SSR) markers. Two out of 30 RAPD primers and nine out of ten SSR primers were able to discriminate all the clones analyzed. Data were confirmed by measuring DNA content using flow cytometry. The results provide a good procedure to improve germplasm field management, in order to removing redundant material in the Annurca collection. This represents an efficient way to create a data bank in order to preserve the genetic variability of the Annurca cultivar. M. Iannaccone, D. Palumbo and I. Ventimiglia contributed equally to this work     

Genetic and molecular markers of the Queensland fruit fly, Bactrocera tryoni

Twenty-six microsatellite markers, along with two restriction fragment length polymorphism (RFLP) markers and three morphological markers, have been mapped to five linkage groups, corresponding to the five autosomes of the Queensland fruit fly, Bactrocera tryoni. All these molecular and genetic markers were genotyped in three-generation pedigrees. Eight molecular markers were also localized to the salivary gland polytene chromosomes by in situ hybridization. This provides a substantial starting point for an integrated genetic and physical map of B. tryoni.     

The shaded side of apple fruit becomes more sensitive to photoinhibition with fruit development

Developmental changes of photochemical and non-photochemical processes and the antioxidant system in the shaded peel vs the sun-exposed peel of 'Gala' apple and their responses to sudden exposure of high light were determined to understand the susceptibility of the shaded peel to high light damage with fruit development. As fruit developed, actual PSII efficiency of the shaded peel decreased, whereas non-photochemical quenching (mainly the slow component) increased at any given PFD. Photochemical quenching coefficient of the shaded peel decreased at any given PFD with fruit development. As fruit developed, the activity of superoxide dismutase, ascorbate peroxidase and dehydroascorbate reductase and the level of reduced ascorbate and total ascorbate decreased; the activity of monodehydroascorbate reductase and glutathione reductase remained low, whereas catalase activity and the level of reduced glutathione and total glutathione increased in the shaded peel. Exposure to high light (1500 micromol m(-2) s(-1)) for 2 h significantly decreased the maximum quantum efficiency of PSII (F(V)/F(M)) in the shaded peel at each developmental stage, with the decrease being larger with fruit development. The F(V)/F(M) of the sun-exposed peel was also decreased by the high light treatment, but the decrease was much smaller than that in the shaded peel at each developmental stage. We conclude that the shaded peel of apple fruit becomes more sensitive to photoinhibition with fruit development, and this increased sensitivity is apparently related to the decease in the overall capacity for photosynthesis and photoprotection of the shaded peel with fruit development.     

分子标记的种类及其在作物遗传育种中的应用

分子标记技术近年来发展很快,目前,常用的分子标记主要可以分为基于杂交的分子标记、基于PCR的分子标记、基于限制性酶切和PCR结合的分子标记以及新一代分子标记.本文对这几类分子标记中常用类型的基本原理进行介绍,并从分子标记在作物种质遗传多样性、基因定位和基因克隆以及分子标记辅助选择育种和分子设计育种中应用进行了阐述.     

适于蛹虫草遗传多样性研究的线粒体分子标记的筛选

摘要:【目的】从蛹虫草线粒体DNA中寻找适于遗传多样性研究的分子标记。【方法】通过PCR扩增和序列分析,比较了20个蛹虫草菌株在12个线粒体DNA片段和3个细胞核DNA片段上的序列变异。【结果】蛹虫草在线粒体DNA上的变异水平高于核DNA,主要表现为线粒体基因内含子的插入缺失多样性和较多的碱基变异位点。不同线粒体DNA片段的变异水平也有差异,而且内含子蛋白比外显子编码的蛋白质更易发生氨基酸的改变。增加使用的分子标记数目,其所揭示的遗传多样性程度也在逐渐提高。【结论】我们依 次推荐nad3-cox2、cox2-nad5、cox2、cox3、cob和cox1这6个线粒体DNA位点用于今后蛹虫草遗传多样性或群体遗传结构的分析。     

Patterns of inheritance with RAPD molecular markers reveal novel types of polymorphism in the honey bee

Summary The polymerase chain reaction (PCR) was used to generate random amplified polymorphic DNA (RAPD) from honey bee DNA samples in order to follow the patterns of inheritance of RAPD markers in a haplodiploid insect. The genomic DNA samples from two parental bees, a haploid drone and a diploid queen, were screened for polymorphism with 68 different tennucleotide primers of random sequence. Parents were scored for the presence or absence of individual bands. An average of 6.3 bands and 1.3 polymorphisms for presence/absence were observed per primer between the parents. Thirteen of these primers were used to determine the inheritance of RAPD marker alleles in the resulting progeny and in haploid drones from a daughter queen. Four types of polymorphisms were observed. Polymorphisms for band presence/absence as well as for band brightness were inherited as dominant markers, meeting Mendelian expectations in haploid and diploid progeny. Polymorphisms for fragment-length were also observed. These segregated in a near 11 ratio in drone progeny. The last type of polymorphism was manifested as a diploid-specific band. Mixing of amplification products after PCR showed that the diploid-specific band was the result of heteroduplex formation from the DNA of alternate alleles in heterozygotes. In two of the four cases of heteroduplex formation, the alternative alleles were manifested as small fragment-length polymorphisms, resulting in co-dominant markers. This is the first demonstration that a proportion of RAPD markers are not inherited in a dominant fashion.     

Composition and distribution of internal resistance in three types of microbial fuel cells

High internal resistance is a key problem limiting the power output of the microbial fuel cell (MFC). Therefore, more knowledge about the internal resistance is essential to enhance the performance of the MFC. However, different methods are used to determine the internal resistance, which makes the comparison difficult. In this study, three different types of MFCs were constructed to study the composition and distribution of internal resistance. The internal resistance (R _i) is partitioned into anodic resistance (R _a), cathodic resistance (R _c), and ohmic resistance () according to their origin and the design of the MFCs. These three resistances were then evaluated by the “current interrupt” method and the “steady discharging” method based on the proposed equivalent circuits for MFCs. In MFC-A, MFC-B, and MFC-C, the R _i values were 3.17, 0.35, and 0.076 Ω m², the values were 2.65, 0.085, and 0.008 Ω m², the R _a values were 0.055, 0.115, and 0.034 Ω m², and the R _c values were 0.466, 0.15, and 0.033 Ω m², respectively. For MFC-B and MFC-C, the remarkable decrease in R _i compared with the two-chamber MFC was mainly ascribed to the decline in and R _c. In MFC-C, the membrane electrodes’ assembly lowered the ohmic resistance and facilitated the mass transport through the anode and cathode electrodes, resulting in the lowest R _i among the three types.     

Response of female oriental fruit moth to volatiles from apple and peach trees at three phenological stages

The attractiveness of peach ( Prunus persica L. Batsch) and apple ( Malus domestica L. Borkh.) (both Rosaceae) tissue to gravid female oriental fruit moth, Grapholita (=  Cydia ) molesta (Busck) (Lepidoptera: Tortricidae), was assessed at three distinct stages throughout the growing season using a dual-choice bioassay. Plant material offered to the female moths consisted of a plant shoot in early spring, before fruit became available. Later, it consisted of a leaf-bearing twig and a fruit, either alone or in combination. The level of attraction of the female moths to the various plant tissues varied substantially over time and according to the plant species. Before fruit became available, female moths were significantly attracted to peach as well as to apple shoots. During the early fruit growth stage, moths were attracted to a leaf-bearing twig originating from a peach tree, but not to that from an apple tree. In peach, it was the vegetative tissue that accounted for the attraction, whereas in apple, it was the reproductive tissue (a developing fruit). During the late fruit growth stage, both peach fruit and apple fruit were highly attractive, whereas a twig with leaves from either an apple or a peach tree was neither attractive nor repellent to the female moths. This changing female olfactory response to volatiles emitted by vegetative tissue and fruits from the two host plant species with progressing season is discussed with respect to the biology and the dispersal of this moth species.