Diversity arrays technology (DArT) markers in apple for genetic linkage maps

Diversity Arrays Technology (DArT) provides a high-throughput whole-genome genotyping platform for the detection and scoring of hundreds of polymorphic loci without any need for prior sequence information. The work presented here details the development and performance of a DArT genotyping array for apple. This is the first paper on DArT in horticultural trees. Genetic mapping of DArT markers in two mapping populations and their integration with other marker types showed that DArT is a powerful high-throughput method for obtaining accurate and reproducible marker data, despite the low cost per data point. This method appears to be suitable for aligning the genetic maps of different segregating populations. The standard complexity reduction method, based on the methylation-sensitive PstI restriction enzyme, resulted in a high frequency of markers, although there was 52–54% redundancy due to the repeated sampling of highly similar sequences. Sequencing of the marker clones showed that they are significantly enriched for low-copy, genic regions. The genome coverage using the standard method was 55–76%. For improved genome coverage, an alternative complexity reduction method was examined, which resulted in less redundancy and additional segregating markers. The DArT markers proved to be of high quality and were very suitable for genetic mapping at low cost for the apple, providing moderate genome coverage

A Comprehensive Review of Immunoreceptor Regulation of Osteoclasts

Osteoclasts require coordinated co-stimulation by several signaling pathways to initiate and regulate their cellular differentiation. RANKL (Receptor Activator for NFkB ligand or TNFSF25), a TNF (tumor necrosis factor) superfamily member, is the master cytokine required for osteoclastogenesis with essential co-stimulatory signals mediated by ITAM (immunoreceptor tyrosine-based activation motif)-signaling adaptors, DAP12 (DNAX associated protein 12kD size) and FcRγ (FcεR1 gamma chain). The ITAM-signaling adaptors do not have an extracellular ligand-binding domain, and therefore must pair with ligand-binding immunoreceptors to interact with their extracellular environment. DAP12 pairs with a number of different immunoreceptors including TREM-2 (Triggering Receptor Expressed on Myeloid Cells 2), MDL-1 (Myeloid Dap-12 associated Lectin) and Siglec-15 (Sialic acid-binding immunoglobulin-type lectin15), while FcRγ pairs with a different set of receptors including OSCAR (Osteoclast Specific Activating Receptor), PIR-A (Paired Immunoglobulin Receptor A), and Fc Receptors. The ligands for many of these receptor in the bone microenvironment remain unknown. Here we will review immunoreceptors known to pair with either DAP12 or FcRγ that have been shown to regulate osteoclastogenesis, However, co-stimulation and the effects of ITAM-signaling have turned out to be complex including paradoxical findings that ITAM-signaling adaptor-associated receptors can inhibit osteoclastogenesis and ITIM (immunoreceptor tyrosine-based inhibitory motif) receptors can promote osteoclastogenesis. Thus, co-stimulation of osteoclastogenesis continues to reveal additional complexities that are important in the regulatory mechanisms that seek to maintain bone homeostasis