Williams & Blangero (1999) derived closed form expressions for the power of a univariate variance components test of linkage for a variety of pedigree structures. We have extended their results by investigating the effect of including monozygotic twins in the design on the power to detect linkage. Specifically, we determined the power associated with a pedigree of size three, where individuals ...

Quantitative-trait association studies have been widely used in search for genetic loci for complex traits in recent years. Yet, fiscal constraints still prohibit many on-going research projects from recruiting a large number of individuals for genotyping to reach a desired level of statistical power. Accordingly, in this article, we describe a novel sib pair sampling strategy for genotyping in...

We used iterative association mapping to identify a susceptibility gene for age-related macular degeneration (AMD) on chromosome 10q26, which is one of the most consistently implicated linkage regions for this disorder. We employed linkage analysis methods, followed by family-based and case-control association analyses, using two independent data sets. To identify statistically the most likely ...

There is a long history of using allele sharing distance (ASD) and closely related metrics for population stratification analysis. However, the theory for this practical usage has not been reported. In this paper, we describe the theoretical background for using ASD on single nucleotide polymorphism (SNP) genetic data for human population stratification analysis. In showing the proof, we lay th...

Genetic data are becoming increasingly important in ecology and conservation biology. This article presents a novel method for estimating population size from DNA profiles obtained from a random sample of individuals. The underlying idea is that the degree of biological relationship between individuals in the sample reflects the size of the population and that DNA profiles provide information a...

Starting with a test statistic for linkage analysis based on allele sharing, we propose an associated one-parameter model. Under general missing-data patterns, this model allows exact calculation of likelihood ratios and LOD scores and has been implemented by a simple modification of existing software. Most important, accurate linkage tests can be performed. Using an example, we show that some ...

High-throughput sequencing technology enables population-level surveys of human genomic variation. Here, we examine the joint allele frequency distributions across continental human populations and present an approach for combining complementary aspects of whole-genome, low-coverage data and targeted high-coverage data. We apply this approach to data generated by the pilot phase of the Thousand...

Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, is a chronic, debilitating, and expensive condition affecting millions of people globally. There is significant variation in the quality of care for patients with IBD across North America, Europe, and Asia; this variation suggests poor quality of care due to overuse, underuse, or misuse of health services a...

Linkage analysis using allele-sharing methods is a trait-model free approach to test for the location of a disease gene by studying the joint inheritance pattern of genes at different loci. For large pedigrees, the space of inheritance vectors becomes large and unavailability of data on individuals makes the probability computation of multilocus inheritance pattern almost infeasible. MCMC techn...

Background: Inflammatory bowel disease (IBD) is a chronic disease with a relapsing course of inflammation in the digestive system. Endoscopy and histopathology are the golden standard methods for detection and assessment of IBD. A distinct increase of fecal calprotectin level can be a useful marker for the diagnosis of IBD. The aim of this study was to evaluate the fecal calprotectin level in p...