Overview of the Rapid Response data.

The Type I Diabetes Genetics Consortium (T1DGC) Rapid Response Workshop was established to evaluate published candidate gene associations in a large collection of affected sib-pair (ASP) families. We report on our quality control (QC) and preliminary family-based association analyses. A random sample of blind duplicates was analyzed for QC. Quality checks, including examination of plate-panel yield, marker yield, Hardy-Weinberg equilibrium, mismatch error rate, Mendelian error rate, and allele distribution across plates, were performed. Genotypes from 2324 families within nine cohorts were obtained from a panel of 21 candidate genes, including 384 single-nucleotide polymorphisms on two genotyping platforms performed at the Broad Institute Center for Genotyping and Analysis (Cambridge, MA, USA). The T1DGC Rapid Response project, following rigorous QC procedures, resulted in a 2297 family, 9688 genotyped individual database on a single-candidate gene panel. The available data include 9005 individuals with genotype data from both platforms and 683 individuals genotyped (276 in Illumina; 407 in Sequenom) on only one platform.

Molecular analysis of the Doppia transposable element of maize.

Doppia (Dop) transposable elements were first identified from element termini found in the upstream portions of certain alleles of the pl1 and r1 loci of maize. At the r1 locus, these Dop end sequences are present in a region called sigma, which functions as the promoter for the S genes of the R-r haplotype, and which is required for efficient epigenetic modification of the S genes during paramutation. In order to better understand the significance of the Dop element sequences at R-r, and to investigate the Dop-encoded products that might regulate r1 genes in this haplotype, we have cloned a more complete Dop element, Dop4. The Dop4 element can encode two proteins that have strong sequence similarity to the TnpA and TnpD proteins of the well characterized maize transposable element En/Spm. The DOPA protein, which is similar to TnpA of En/Spm, is shown to bind to short, subterminal repeat motifs located in the Dop element ends. Like TnpA, DOPA promotes intermolecular associations between DNA molecules. In contrast to the activity of TnpA, which is a transcriptional repressor of En/Spm, DOPA activates expression of reporter genes driven by either the Dop promoter or sigma in transient expression assays.