Genomics goes chromosomal to explore the wheat genome

OBJECTIVES: The implant design and surface modification are independent conditions that can alter the implant bone response. The objective of this study is to compare the bone response to roughened tapered and cylindrical screw-type implants with and without hydroxyapatite (HA) surface coating in the femoral trabecular bone of rabbits. MATERIAL AND METHOD: Thirty-two implants (8 x 3.5 mm) consisting of four different types (eight implants in each group), that is, tapered implants, cylindrical implants, HA-coated tapered implants, and HA-coated cylindrical implants were installed in the femoral condyle of 16 rabbits. After 8 weeks of healing, the femoral condyles were retrieved and studied histologically. The bone-to-implant contact percentage was assessed and analyzed statistically. Results : The histomorphometric analysis revealed that the bone-to-implant contact (BIC) values seemed to be higher for HA-coated tapered implants (65.62 +/- 13.02) followed by cylindrical non-coated implants. All four types of implants showed wide distribution of BIC with no statistical significance between different types of implants. CONCLUSION: It can be concluded that under the current experimental conditions, implant design and surface composition had little effect on the bone-to-implant interface

Second-generation chromosome-specific BAC resources in wheat

In the societal and scientific discussions about the support for democracy and gender equality in the Arab Middle East, this study engages the triangular theory, which predicts that Islamic orientations influence gender equality attitudes and democracy negatively, and attitudes towards gender equality are also expected to lead to more democratic support, partly channelling the influence of Islam. This theory was tested on Arab Barometer data for seven countries, including three different dimensions of Islamic-religious identity: affiliation, piety, and political-Islamist attitudes. The analyses roughly back the triangular model, but for democratic support only the Islamist values seem important, partly working through economic gender equality attitudes. Attitudes towards women’s position in politics and education seem unrelated to democratic support. In addition, this study applies the gender and postcolonial concept of ‘othering’ to the triangular model. Theoretically it predicts that in the current neo-colonial era, anti-Western feelings might create more Islamic and less democracy and gender equal attitudes simultaneously, making Islam’s impact partly spurious. Empirically, this is modestly supported for the Islamist-democracy link only. However, anti-Western feelings do relate to gender equality, democratic support, and religious attitudes, and deserves more attention when studying democracy and gender equality in the Arab Middle East

Flow sorting and sequencing meadow fescue chromosome 4F.

Analysis of large genomes is hampered by a high proportion of repetitive DNA, which makes the assembly of short sequence reads difficult. This is also the case in meadow fescue (Festuca pratensis), which is known for good abiotic stress resistance and it has been used in intergeneric hybridization with ryegrasses to produce Festulolium cultivars. In this work we describe a new approach to analyze the large genome of meadow fescue, which involves reduction of sample complexity without compromising information content. This is achieved by dissecting the genome to smaller parts - individual chromosomes and groups of chromosomes. As the first step, we flow-sorted chromosome 4F and sequenced it by Illumina with ~50x coverage. This provided the first insight into the composition of the fescue genome, enabled the construction of virtual gene order of the chromosome, and facilitated detailed comparative analysis with the sequenced genomes of rice, Brachypodium, Sorghum and barley. Using GenomeZipper, we were able to confirm collinearity of chromosome 4F with barley chromosome 4H and the long arm of chromosome 5H (5HL). Several new tandem repeats were identified and physically mapped using FISH. They were found as robust cytogenetic markers for karyotyping of meadow fescue and ryegrass species and their hybrids. The ability to purify chromosome 4F opens a way for more efficient analysis of genomic loci on this chromosome underlying important traits, including freezing tolerance. Our results confirm that next generation sequencing of flow-sorted chromosomes enables an overview on chromosome structure and evolution at a resolution never achieved before

A chromosome-based draft sequence of the hexaploid bread wheat (<em>Triticum aestivum</em>) genome.

An ordered draft sequence of the 17-gigabase hexaploid bread wheat (Triticum aestivum) genome has been produced by sequencing isolated chromosome arms. We have annotated 124,201 gene loci distributed nearly evenly across the homeologous chromosomes and subgenomes. Comparative gene analysis of wheat subgenomes and extant diploid and tetraploid wheat relatives showed that high sequence similarity and structural conservation are retained, with limited gene loss, after polyploidization. However, across the genomes there was evidence of dynamic gene gain, loss, and duplication since the divergence of the wheat lineages. A high degree of transcriptional autonomy and no global dominance was found for the subgenomes. These insights into the genome biology of a polyploid crop provide a springboard for faster gene isolation, rapid genetic marker development, and precise breeding to meet the needs of increasing food demand worldwide

A chromosome-based draft sequence of the hexaploid bread wheat (Triticum aestivum) genome

An ordered draft sequence of the 17-gigabase hexaploid bread wheat (Triticum aestivum) genome has been produced by sequencing isolated chromosome arms. We have annotated 124,201 gene loci distributed nearly evenly across the homeologous chromosomes and subgenomes. Comparative gene analysis of wheat subgenomes and extant diploid and tetraploid wheat relatives showed that high sequence similarity and structural conservation are retained, with limited gene loss, after polyploidization. However, across the genomes there was evidence of dynamic gene gain, loss, and duplication since the divergence of the wheat lineages. A high degree of transcriptional autonomy and no global dominance was found for the subgenomes. These insights into the genome biology of a polyploid crop provide a springboard for faster gene isolation, rapid genetic marker development, and precise breeding to meet the needs of increasing food demand worldwide