TL;DR: DArT proved more robust to genome size and ploidy-level differences among approximately 60 organisms for which DArT was developed to date compared to other high-throughput genotyping technologies.
Abstract: In the last 20 years, we have observed an exponential growth of the DNA sequence data and simular increase in the volume of DNA polymorphism data generated by numerous molecular marker technologies. Most of the investment, and therefore progress, concentrated on human genome and genomes of selected model species. Diversity Arrays Technology (DArT), developed over a decade ago, was among the first "democratizing" genotyping technologies, as its performance was primarily driven by the level of DNA sequence variation in the species rather than by the level of financial investment. DArT also proved more robust to genome size and ploidy-level differences among approximately 60 organisms for which DArT was developed to date compared to other high-throughput genotyping technologies. The success of DArT in a number of organisms, including a wide range of "orphan crops," can be attributed to the simplicity of underlying concepts: DArT combines genome complexity reduction methods enriching for genic regions with a highly parallel assay readout on a number of "open-access" microarray platforms. The quantitative nature of the assay enabled a number of applications in which allelic frequencies can be estimated from DArT arrays. A typical DArT assay tests for polymorphism tens of thousands of genomic loci with the final number of markers reported (hundreds to thousands) reflecting the level of DNA sequence variation in the tested loci. Detailed DArT methods, protocols, and a range of their application examples as well as DArT's evolution path are presented.
TL;DR: Diversity Arrays Technology can be effectively applied to genetic mapping and diversity analyses of barley and is highlighted as a generic technique for genome profiling in the context of molecular breeding and genomics.
Abstract: Diversity Arrays Technology (DArT) can detect and type DNA variation at several hundred genomic loci in parallel without relying on sequence information. Here we show that it can be effectively applied to genetic mapping and diversity analyses of barley, a species with a 5,000-Mbp genome. We tested several complexity reduction methods and selected two that generated the most polymorphic genomic representations. Arrays containing individual fragments from these representations generated DArT fingerprints with a genotype call rate of 98.0% and a scoring reproducibility of at least 99.8%. The fingerprints grouped barley lines according to known genetic relationships. To validate the Mendelian behavior of DArT markers, we constructed a genetic map for a cross between cultivars Steptoe and Morex. Nearly all polymorphic array features could be incorporated into one of seven linkage groups (98.8%). The resulting map comprised ≈385 unique DArT markers and spanned 1,137 centimorgans. A comparison with the restriction fragment length polymorphism-based framework map indicated that the quality of the DArT map was equivalent, if not superior, to that of the framework map. These results highlight the potential of DArT as a generic technique for genome profiling in the context of molecular breeding and genomics.
TL;DR: Three major changes allowed us to improve DART accuracy by a factor of three: more accurate simulation of single and multiple scattering, use of a scheme that oversamples DART cells and a better account of the direction of radiation that gives rise to multiple scattered radiation.
Abstract: DART (Discrete Anisotropic Radiative Transfer) is a radiative transfer model that simulates remotely acquired images. It was originally developed to work in the short wavelengths (0.3–3 µm) within 3D natural scenes that are represented as matrices of rectangular cells containing trees, shrubs, grass, soil, etc. DART was recently modified to extend its domain of application and to improve its accuracy. This paper summarizes the major features of DART and presents the changes that were implemented for improving its accuracy. Presently, this model works with natural and urban landscapes, on the whole optical domain (thermal infrared included) and with a multispectral approach that uses optical data bases from 0.3 µm up to 15 µm. It simulates radiative transfer in the whole ‘atmosphere–Earth’ system and it accounts for the instrumental transfer function. Three major changes allowed us to improve DART accuracy by a factor of three: more accurate simulation of single and multiple scattering, use of a scheme tha...
TL;DR: Direct analysis in real time (DART) is a new tool that complements electrospray ionization for the rapid ionization and subsequent mass spectral analysis of compounds in drug discovery.
Abstract: Direct analysis in real time (DART) is a novel ionization technique that provides for the rapid ionization of small molecules under ambient conditions. In this study, several commercially available drugs as well as actual compounds from drug discovery research were examined by LC/UV/ESI-MS and DART interfaced to a quadrupole mass spectrometer. For most compounds, the molecular ions observed by ESI-MS were observed by DART/MS. DART/MS was also studied as a means to quickly monitor synthetic organic reactions and to obtain nearly instantaneous molecular weight confirmations of final products in drug discovery. For simple, synthetic organic transformations, the trends in the intensities of the mass spectral signals for the reactant and product obtained by DART/MS scaled closely with those of the diode array or the total ion chromatogram obtained by LC/UV/ESI-MS. In summary, DART is a new tool that complements electrospray ionization for the rapid ionization and subsequent mass spectral analysis of compounds ...
TL;DR: A Diversity Arrays Technology platform for durum wheat is developed to enable efficient and cost-effective mapping and molecular breeding applications and combines DArT and SSR platforms provides an efficient and rapid method of generating linkage maps in durum Wheat.
Abstract: Genetic mapping in durum wheat (Triticum durum Desf.) is constrained by its large genome and allopolyploid nature. We developed a Diversity Arrays Technology (DArT) platform for durum wheat to enable efficient and cost-effective mapping and molecular breeding applications. Genomic representations from 56 durum accessions were used to assemble a DArT genotyping microarray. Microsatellite (SSR) and DArT markers were mapped on a durum wheat recombinant inbred population (176 lines). The integrated DArT-SSR map included 554 loci (162 SSRs and 392 DArT markers) and spanned 2022 cM (5 cM/marker on average). The DArT markers from durum wheat were positioned in respect to anchor SSRs and hexaploid wheat DArT markers. DArT markers compared favourably to SSRs to evaluate genetic relationships among the durum panel, with 1315 DArT polymorphisms found across the accessions. Combining DArT and SSR platforms provides an efficient and rapid method of generating linkage maps in durum wheat.