Extensive duplication of the Wolbachia DNA in chromosome four of Drosophila ananassae.

Background: Lateral gene transfer (LGT) from bacterial Wolbachia endosymbionts has been detected in ~20% of arthropod and nematode genome sequencing projects. Many of these transfers are large and contain a substantial part of the Wolbachia genome.

Results: Here, we re-sequenced three D.

Bitter taste receptors influence glucose homeostasis.

TAS1R- and TAS2R-type taste receptors are expressed in the gustatory system, where they detect sweet- and bitter-tasting stimuli, respectively. These receptors are also expressed in subsets of cells within the mammalian gastrointestinal tract, where they mediate nutrient assimilation and endocrine responses. For example, sweeteners stimulate taste receptors on the surface of gut enteroendocrine L cells to elicit an increase in intracellular Ca(2+) and secretion of the incretin hormone glucagon-like peptide-1 (GLP-1), an important modulator of insulin biosynthesis and secretion.

A null mutation in human APOC3 confers a favorable plasma lipid profile and apparent cardioprotection.

Apolipoprotein C-III (apoC-III) inhibits triglyceride hydrolysis and has been implicated in coronary artery disease. Through a genome-wide association study, we have found that about 5% of the Lancaster Amish are heterozygous carriers of a null mutation (R19X) in the gene encoding apoC-III (APOC3) and, as a result, express half the amount of apoC-III present in noncarriers. Mutation carriers compared with noncarriers had lower fasting and postprandial serum triglycerides, higher levels of HDL-cholesterol and lower levels of LDL-cholesterol.

Identification of novel candidate genes for type 2 diabetes from a genome-wide association scan in the Old Order Amish: evidence for replication from diabetes-related quantitative traits and from independent populations.

Objective: We sought to identify type 2 diabetes susceptibility genes through a genome-wide association scan (GWAS) in the Amish.

Research Design And Methods: DNA from 124 type 2 diabetic case subjects and 295 control subjects with normal glucose tolerance were genotyped on the Affymetrix 100K single nucleotide polymorphism (SNP) array. A total of 82,485 SNPs were tested for association with type 2 diabetes.

Polymorphisms in the transcription factor 7-like 2 (TCF7L2) gene are associated with type 2 diabetes in the Amish: replication and evidence for a role in both insulin secretion and insulin resistance.

Transcription factor 7-like 2 (TCF7L2) regulates genes involved in cell proliferation and differentiation. The TCF7L2 gene is located on chromosome 10q25 in a region of replicated linkage to type 2 diabetes. Recently, a microsatellite marker in intron 3 (DG10S478) and five correlated single nucleotide polymorphisms (SNPs) were identified in Icelandic individuals that showed strong association with type 2 diabetes, which was replicated in Danish and European-American cohorts.

Genetic variation in adiponectin receptor 1 and adiponectin receptor 2 is associated with type 2 diabetes in the Old Order Amish.

Adiponectin receptor 1 (ADIPOR1) and adiponectin receptor 2 (ADIPOR2) are newly identified receptors for adiponectin, an adipocytokine with anti-inflammatory and insulin-sensitizing properties. We screened for polymorphisms by performing sequence analysis on all eight exons, splice junctions, and approximately 2 kb of the 5' flanking regions of each receptor. We detected 5 single nucleotide polymorphisms (SNPs) in ADIPOR1 and 16 SNPs in ADIPOR2.

Linkage of plasma adiponectin levels to 3q27 explained by association with variation in the APM1 gene.

We performed a genome-wide linkage scan of plasma adiponectin levels in 569 nondiabetic participants in the Amish Family Diabetes Study. The highest logarithm of odds (LOD) score (2.13; P = 0.

Polymorphisms in both promoters of hepatocyte nuclear factor 4-alpha are associated with type 2 diabetes in the Amish.

Hepatocyte nuclear factor 4-alpha (HNF4A) is a transcription factor located on chromosome 20q13 that regulates expression of genes involved in glucose metabolism and homeostasis. Recently, two groups independently identified single nucleotide polymorphism (SNPs) in an alternate upstream promoter (P2) of HNF4A that were associated with type 2 diabetes in Ashkenazi Jews and Finns. We genotyped haplotype-tagging SNPs (htSNPs) across the two promoter regions and the coding region of HNF4A in individuals with type 2 diabetes (n = 137), impaired glucose tolerance (IGT) (n = 139), and normal glucose tolerance (n = 342) from the Amish Family Diabetes Study (AFDS) to test for association with type 2 diabetes.

Polymorphism in the calsequestrin 1 (CASQ1) gene on chromosome 1q21 is associated with type 2 diabetes in the old order Amish.

Calsequestrin (CASQ)1 is involved in intracellular storage and release of calcium, a process that has been shown to mediate glucose transport in muscle. Its gene, CASQ1, is encoded on chromosome 1q21, a region that has been linked to type 2 diabetes in the Amish and several other populations. We screened all 11 exons, exon-intron junctions, and the proximal regulatory region of CASQ1 for mutations.