Analysis of Genetic Diversity and Relationships in a Tunisian Fig （Ficus carica） Germplasm Collection by Random Amplified Microsatellite Polymorphisms

The random amplified mirosatellite polymorphism method was performed in a set of Tunisian fig landraces using eighteen primer combinations. A total of sixty three random amplified microsatellite polymorphism （RAMPO） markers were scored and used either to assess the genetic diversity in these cultivars or to detect cases of mislabeling. Opportunely, data proved that the designed procedure constitutes an attractive and fast method with low costs and prevents radio exposure. As a result, we have identified the primer combinations that are the most efficient to detect genetic polymorphism in this crop. Therefore, the derived unweighted pair-group method with arithmetic averages （UPGMA） dendrogram illustrates the genetic divergence among the landraces studied and exhibits a typically continuous variation. Moreover, no evident correlation between the sexes of trees was observed. In addition, using these markers, discrimination between landraces has been achieved. Thus, random amplified mirosatellite polymor- phism is proved to be powerful for characterizing the local fig germplasm.

Blast-Resistance Inheritance of Space-Induced Rice Lines and Their Genomic Polymorphism by Microsatellite Markers

To understand the resistance inheritance basis of space-induced rice lines to blast, and to probe mutants＇ genomic DNA polymorphism compared with ground control by microsatellite markers, three space-induced lines were crossed with a highly susceptible variety LTH, and their F1 and F2 populations were inoculated by two representative blast isolates with broad pathogenicity to analyze their resistance inheritance basis. Meanwhile three mutant lines and the ground control were analyzed by 225 rice SSR （simple sequence repeat） primer pairs selected throughout the 12 chromosomes of whole rice genome, to scan the mutagenesis in genome of the mutant lines. The results indicated the blast-resistant genes harbored in these mutant lines were dominant. It was demonstrated that the resistance of mutant H1 to isolate GD0193 and GD3286 was controlled by a single gene, respectively; while mutants H2 and H3 were controlled by two pairs of major genes against isolate GD3286 and H2 showed complicated genetic mechanism to isolate GD0193. H3＇s resistance to isolate GD0193 was verified to be controlled by a single gene. According to the results of SSR analysis, three mutant lines showed different mutant rates as compared with the ground control, and the mutant rates also varied. Resistance genes can be induced from rice by space mutation, and different genomic variations were detected in blast-resistant lines.

Construction of a Normalized Full-Length cDNA Library of Cephalopod Amphioctopus fangsiao and Development of Microsatellite Markers

Amphioctopus fangsiao is one of the most economically important species and has been considered to be a candidate for aquaculture. In order to facilitate its fine-scale genetic analyses, we constructed a normalized full-length library successfully and developed a set of microsatellite markers in this study. The normalized full-length library had a storage capacity of 6.9×105 independent clones. The recombination efficiency was 95% and the average size of inserted fragments was longer than 1000 bp. A total of 3440 high quality ESTs were obtained, which were assembled into 1803 unigenes. Of these unigenes, 450(25%) were assigned into 33 Gene Ontology terms, 576(31.9%) into 153 Kyoto Encyclopedia of Genes and Genomes pathways, and 275(15.3%) into 22 Clusters of Orthologous Groups. Seventy-six polymorphic microsatellite markers were identified. The number of alleles per locus ranged from 4 to 17, and the observed and expected heterozygosities varied between 0.167 and 0.967 and between 0.326 and 0.944, respectively. Twelve loci were significantly deviated from Hardy-Weinberg equilibrium after Bonferroni correction and no linkage disequilibrium was found between different loci. This study provided not only a useful resource for the isolation of the functional genes, but also a set of informative microsatellites for the assessment of population structure and conservation genetics of A. fangsiao.

Genetic diversity in two threatened species in Vietnam:Taxus chinensis and Taxus wallichiana

Taxus chinensis and T. wallichiana in have been threatened in their distribution areas in recent decades because of their over-exploitation and reduction and destruction of native habitats. Determining the genetic diversity in populations of the two species will provide guidelines for their protection and preservation. Two hundred and fifteen trees from six populations of T. chinensis and150 sampled trees of T. wallichiana were sampled. Six microsatellite primer pairs selected from 16 primer pairs were used to investigate genetic variation at the population and species levels. Five yielded polymorphic alleles, and among the 13 putative alleles amplified, 11 were polymorphic（accounting for 76.33 %）.Shannon＇s information index（I） and percentage of polymorphic bands（PPB）（I = 0.202 and PPB = 67.22 % for T. chinensis; I = 0.217 and PPB = 65.03 % for T. wallichiana）. Both species had low levels of genetic diversity（mean Ho= 0.107, He= 0.121 for T. chinensis; Ho= 0.095, He= 0.109 for T. wallichiana）. Genetic differentiation among populations was higher（FST= 0.189） for T. chinensis and lower（0.156） for T.wallichiana, indicating limited gene flow（Nm） among populations for T. chinensis（0.68） and T. wallichiana（0.65）.Variation among individuals of T. chinensis was 63.59 and73.12 % for T. wallichiana. Thus, the threatened status of the two conifers is related to a lack of genetic diversity. All populations are isolated in small forest remnants. An ex situ conservation site should be established with a new population for these species that comprises all the genetic groups for the best chance to improve their fitness under environmental stresses.

Development and Characterization of Fifteen Polymorphic M icosatellites for Extremely Endangered Salamander, Echinotriton chinhaiensis

Echinotriton chinhaiensis is a critically endangered salamander and its distribution is restricted to Ningbo, Zhejiang Province of China. In this study, we developed and characterized fifteen polymorphic microsatellite loci for E. ehinhaiensis from dinucleotide- and tetranucleotide- enriched library. The number of alleles ranges from 4 to 12 with an average of 7.27 alleles per locus. The observed and expected heterozygosities values were from 0.250 to 0.844 and 0.511 to 0.872 with an average value of 0.596 and 0.722; respectively. The polymorphic microsatellite loci described in this paper are useful in the further study on genetic diversity and gene flow, which would be helpful to formulate effective conservation strategies for the E. chinhaiensis.

Genotype and allele frequencies of heme oxygenase-1 promoter region in a Greek cohort

Background Heme oxygenase-1 （HO-1） is an enzyme, which catabolizes heme into carbon monoxide, biliverdin and free iron. The induction of this enzyme is an important cytoprotective mechanism, which occurs as an adaptive and beneficial response to a wide variety of oxidant stimuli. HO-1 inducibility is mainly modulated by a （GT）n polymorphism in the promoter region, and has been shown that short （S） repeats are associated with greater up-regulation of HO-1, compared with long （L） repeats. Methods In the present study, 250 healthy Greek individuals have been screened in order to estimate the frequencies of （GT）n alleles in the HO-1 gene. Results Nineteen different alleles, ranging from 17 to 39 repeats, with （GT）23 and （GT）3obeing the most common ones, were identified. Conclusion The possible role of this polymorphism in disease states is discussed.