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Diverse Phenotypes (diverse + phenotype)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Not really identical: Epigenetic differences in monozygotic twins and implications for twin studies in psychiatry,

AMERICAN JOURNAL OF MEDICAL GENETICS, Issue 2 2009
F. Nipa Haque
Abstract Classical twin studies in the field of psychiatry generally fall into one of two categories: (1) those designed to identify environmental risk factors causing discordance in monozygotic (MZ) twins and (2) those geared towards identifying genetic risk factors. However, neither environment nor differences in DNA sequence can fully account for phenotypic discordance among MZ twins. The field of epigenetics , DNA modifications that can affect gene expression , offers new models to understand discordance in MZ twins. In the past, MZ twins were regarded as genetically-identical controls for differing environmental conditions. In contrast, the evolving current concept is that epigenetic differences between MZ twins may modulate differences in diverse phenotype, from disease to personality. In this article, we review some twin studies, and discuss the dynamic interactions between stochastic, environmental, and epigenetic variables that influence neurobiological phenotypes. © 2009 Wiley-Liss, Inc. [source]

Quorum-sensing in Gram-negative bacteria

FEMS MICROBIOLOGY REVIEWS, Issue 4 2001
Neil A Whitehead
Abstract It has become increasingly and widely recognised that bacteria do not exist as solitary cells, but are colonial organisms that exploit elaborate systems of intercellular communication to facilitate their adaptation to changing environmental conditions. The languages by which bacteria communicate take the form of chemical signals, excreted from the cells, which can elicit profound physiological changes. Many types of signalling molecules, which regulate diverse phenotypes across distant genera, have been described. The most common signalling molecules found in Gram-negative bacteria are N -acyl derivatives of homoserine lactone (acyl HSLs). Modulation of the physiological processes controlled by acyl HSLs (and, indeed, many of the non-acyl HSL-mediated systems) occurs in a cell density- and growth phase-dependent manner. Therefore, the term ,quorum-sensing' has been coined to describe this ability of bacteria to monitor cell density before expressing a phenotype. In this paper, we review the current state of research concerning acyl HSL-mediated quorum-sensing. We also describe two non-acyl HSL-based systems utilised by the phytopathogens Ralstonia solanacearum and Xanthomonas campestris. [source]

Floxed allele for conditional inactivation of the GABAB(1) gene

GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 3 2004
Corinne Haller
Abstract GABAB receptors are the G-protein-coupled receptors for the neurotransmitter GABA. GABAB receptors are broadly expressed in the nervous system. Their complete absence in mice causes premature lethality or,when mice are viable,epilepsy, impaired memory, hyperalgesia, hypothermia, and hyperactivity. A spatially and temporally restricted loss of GABAB function would allow addressing how the absence of GABAB receptors leads to these diverse phenotypes. To permit a conditional gene inactivation, we flanked critical exons of the GABAB(1) gene with lox511 sites. GABAB(1)lox511/lox511 mice exhibit normal levels of GABAB(1) protein, are fertile, and do not display any behavioral phenotype. We crossed GABAB(1)lox511/lox511 with Cre-deleter mice to produce mice with an unrestricted GABAB receptor elimination. These GABAB(1),/, mice no longer synthesize GABAB(1) protein and exhibit the expected behavioral abnormalities. The conditional GABAB(1) allele described here is therefore suitable for generating mice with a site- and time-specific loss of GABAB function. genesis 40:125,130, 2004. © 2004 Wiley-Liss, Inc. [source]

Pseudodominant inheritance of spondylocostal dysostosis type 1 caused by two familial delta-like 3 mutations

CLINICAL GENETICS, Issue 1 2004
NV Whittock
Spondylocostal dysostoses (SCD) are a heterogeneous group of disorders of axial skeletal malformation characterized by multiple vertebral segmentation defects and rib anomalies. Sporadic cases with diverse phenotypes, sometimes including multiple organ abnormalities, are relatively common, and monogenic forms demonstrating autosomal recessive (AR) and, more rarely, autosomal dominant (AD) inheritance have been reported. We previously showed that mutations in delta-like 3 (DLL3), a somitogenesis gene that encodes a ligand for the notch signaling pathway, cause AR SCD with a consistent pattern of abnormal segmentation. We studied an SCD family previously reported to show AD inheritance, in which the phenotype is similar to that in AR cases. Direct DLL3 sequencing of individuals in two generations identified the affected father as homozygous for a novel frameshift mutation, 1440delG. His two affected children were compound heterozygotes for this mutation and a novel missense mutation, G504D, the first putative missense mutation reported in the transmembrane domain of DLL3. Their two unaffected siblings were heterozygotes for the 1440delG mutation. Pseudodominant inheritance has been confirmed, and the findings raise potential consequences for genetic counseling in relation to the SCD disorders. [source]