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At least 1,783 records · Page 99Linked to original sources
PubMed1990

Polymorphisms of HepG2/erythrocyte glucose-transporter gene. Linkage relationships and implications for genetic analysis of NIDDM.

To assess the contribution of the HepG2/erythrocyte glucose-transporter (HepG2 GT) gene to the inherited susceptibility to non-insulin-dependent diabetes mellitus (NIDDM), cDNA and genomic probes were used to search for restriction-endonuclease polymorphisms at this locus. Analysis of DNA from 16 unrelated Black American individuals with 19 enzymes and as many as six different probes, defined four polymorphisms over a 45-kilobase region. Nucleotide diversity (pi = 0.006) was low relative to that at other loci, with an average of 1 in 1700 base pairs different between two chromosomes at this locus. The observed combined heterozygosity for these four sites was 0.69, which indicates that the markers at this locus could be useful for linkage analysis in families. Linkage-disequilibrium values between the four polymorphisms were evaluated by pairwise analysis and extended haplotypes. Calculating pairwise associations by the disequilibrium statistic delta or by another measure of disequilibrium, D' (the maximum likelihood of disequilibrium, which is less dependent on frequency), significant linkage disequilibrium could not be demonstrated. However, the frequencies of the observed extended haplotypes were shown to differ (chi 2 = 9.1, df = 2, P less than 0.025) from predicted frequencies if the sites were in linkage equilibrium in Blacks. The frequencies of these four polymorphisms were determined in Black nondiabetic (n = 44) and NIDDM (n = 63) subjects. Neither the allelic nor genotypic frequencies of the polymorphisms differed between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Black People↗
PubMed2001

An introduction to DNA chips: principles, technology, applications and analysis.

This review describes the recently developed GeneChip technology that provides efficient access to genetic information using miniaturised, high-density arrays of DNA or oligonucleotide probes. Such microarrays are powerful tools to study the molecular basis of interactions on a scale that would be impossible using conventional analysis. The recent development of the microarray technology has greatly accelerated the investigation of gene regulation. Arrays are mostly used to identify which genes are turned on or off in a cell or tissue, and also to evaluate the extent of a gene's expression under various conditions. Indeed, this technology has been successfully applied to investigate simultaneous expression of many thousands of genes and to the detection of mutations or polymorphisms, as well as for their mapping and sequencing.

Gene Expression Profiling↗
PubMed1992

Evaluation of four deoxyribonucleic acid (DNA) extraction protocols for DNA yield and variation in restriction fragment length polymorphism (RFLP) sizes under varying gel conditions.

This study originated from discussions and recommendations of the Technical Working Group on DNA Analysis Methods (TWGDAM). Four bloodstain deoxyribonucleic acid (DNA) extraction protocols and five semen stain DNA extraction protocols were evaluated. Nine laboratories participated in the extraction of DNA from 20 bloodstains and 20 semen stains using each protocol. All blood and semen stains originated from a single donor and were prepared under uniform conditions to permit the direct comparison of DNA yields and restriction fragment lengths. The extracted DNA from approximately 600 bloodstains and 700 semen stains was quantified by yield gel analysis and a slot blot hybridization technique. The extracted DNA was digested and restriction fragment length polymorphism (RFLP) patterns were generated using three single-locus probes. The RFLP sizing data produced from the blood and semen stains were evaluated with respect to (1) DNA extraction method, (2) gel length, (3) agarose type, (4) presence or absence of ethidium bromide in the gel, and (5) fragment sizes obtained from DNA isolated directly from the donor's liquid blood. This study demonstrates conclusively that high-molecular-weight DNA can be isolated using either organic or nonorganic DNA extraction protocols and that the resulting RFLP sizes are highly reproducible regardless of gel length, agarose type, or presence/absence of ethidium bromide.

Autoradiography↗
PubMed2004

Identification and characterization of Crumbs homolog 2 gene at human chromosome 9q33.3.

Drosophila Crumbs (Crb)--Stardust (Sdt)--Discs lost (Dlt) complex plays a pivotal role in the establishment and the maintenance of epithelial polarity. CRB1 and CRB3 are human homologs of Drosophila Crb, MPP1-MPP7 are human homologs of Drosophila Sdt, INADL/PATJ and MPDZ/MUPP1 are human homologs of Drosophila Dlt. Here, we identified and characterized a novel Crumbs family gene, Crumbs homolog 2 (CRB2), by using bioinformatics. CRB2 isoform 1 was assembled by adding nucleotide position 1-3353 of FLJ16786 cDNA (AK123000) to the 5'-end of 5'-truncated FLJ38464 cDNA (NM_173689.1), while that of CRB2 isoform 2 was derived from FLJ16786 cDNA. CRB2 isoform 1, consisting of exon 1-13, encoded a 1285-aa transmembrane protein. CRB2 isoform 2, consisting of exon 1-10 and intron 10, encoded a 1176-aa secreted protein. CRB2 gene was found to encode transmembrane protein as well as secreted protein due to alternative splicing. CRB2 isoform 1, showing 24.4% total amino-acid identity with CRB1, was type I transmembrane protein with 14 extracellular EGF-like domains, 3 extracellular Laminin G-like domains and the Crb cytoplasmic tail (CCT) domain. CCT domain, functioning as the binding site for PDZ domain of Sdt homologs, was conserved among human CRB1, CRB2, CRB3, mouse Crb1, Crb3, Drosophila Crb, and C. elegans crb. Comparative genomics revealed that CRB2-KIAA1608-LHX2-NEK6 locus at human chromosome 9q33.3 and CRB1-MGC27044-LHX9-NEK7 locus at human chromosome 1q31.3 were paralogous regions within the human genome. This is the first report on identification and characterization of the CRB2 gene.

Alternative Splicing↗
PubMedDate not supplied

[A problem of creating a catalog of human erythrocyte membrane proteins].

Properties of human erythrocyte membrane proteins are widely studied recently. Comprehensive data were obtained on two main membrane proteins responsible for essential membrane functions. Besides, high performance two-dimensional electrophoresis and a number of other procedures enabled to detect more than 100 minor proteins in the biomembranes. The latest advances in studies of proteins and their coding genes allowed to compile a catalogue for erythrocyte membrane proteins, which is of importance for investigations in the field of membrane molecular biology. Structural organization of the catalogue for human erythrocyte membrane proteins is discussed.

Catalogs as Topic↗
PubMed1984

Ascertainment and goodness of fit of variance component models for pedigree data.

The multivariate normal parameterization of the polygenic model (Lange et al., 1976) provides a great deal of flexibility for analyzing quantitative data on pedigrees. The likelihood approach employed ensures statistical efficiency and allows for hypothesis testing using the likelihood ratio criterion. The parameterization also facilitates ascertainment correction and goodness-of-fit testing (Spence et al., 1977; Ott, 1979; Hopper and Mathews, 1982; Boehnke, 1983). We reviewed these results and then described a simulation study undertaken to determine their utility when applied to data. Pedigree data were generated under polygenic and mixed models and sampled either randomly or via probands. We found that the variance components of the model were accurately estimated for random sampling, but less so for ascertained data analyzed by conditioning on probands. Goodness-of-fit tests employing test statistics corresponding to individual phenotypes and entire pedigrees were conservative, but pedigree tests did demonstrate reasonable power to reject a variety of mixed model alternatives. In addition, we found that the pedigree test statistics could be used to enrich a sample of pedigrees for those pedigrees segregating at a major locus, providing an objective criterion for choosing pedigrees to be included in a linkage analysis.

Chromosome Mapping↗
PubMed1995

[Genes, behavior and disease. A sceptic's view of gene mapping and gene therapy].

This paper contains four parts. The first focuses on The Human Genome Project (HGP). The concept of a "normal sequence" seems problematic. The second part reviews what is meant by "genetically-caused" and by "a (several) gene(s) for a trait". Genes work in concert, and it is likely that many genes together influence most complex traits. A difference in traits between two individuals, however, can be due to a difference in a single gene, as is the case for several thousand rare "genetic diseases". Such diseases were the original focus of gene therapy. Could gene therapy also be applied to more common complex traits? Diagnostic problems and the unsuccessful attempts to find a single gene difference in patients with manic depressive disorder, schizophrenia and Alzheimer's disease are discussed. Part three reviews future genetic research into complex traits and what kind of treatment can realistically be expected. It is concluded that improved diagnostics is the most likely outcome, not therapy. Part four raises arguments from the emerging Darwinian approach to medicine and states that it is far too early to even think of gene therapy. The needed knowledge about genes, behaviour and disease will not come from the one-sided genetic effort represented by HGP, and the resources should instead be invested in several different approaches to these complex issues.

Behavior↗
PubMed1995

Multipoint interval mapping of quantitative trait loci, using sib pairs.

The sib-pair interval-mapping procedure of Fulker and Cardon is extended to take account of all available marker information on a chromosome simultaneously. The method provides a computationally fast multipoint analysis of sib-pair data, using a modified Haseman-Elston approach. It gives results very similar to those of the earlier interval-mapping procedure when marker information is relatively uniform and a coarse map is used. However, there is a substantial improvement over the original method when markers differ in information content and/or when a dense map is employed. The method is illustrated by using simulated sib-pair data.

Alleles↗
PubMed1997

RIFLE: rapid identification of microorganisms by fragment length evaluation.

Biological macromolecules represent a valuable source of information for the identification and phylogenetic classification of microorganisms. One of the most commonly used macromolecules for this task is the 16S rDNA. The WWW-based RIFLE system presented here supports large-scale identification tasks by comparing 16S rDNA restriction patterns to a database of restriction patterns derived from sequence databases. Computing efficiency and robustness against experimental errors are gained by employing a new distance measure for restriction patterns, the fragment length distance. Results from the application of the system to the identification of uncultured microorganisms associated with the seagrass halophila stipulacea show the reliability of the method.

Algorithms↗
PubMed1997

Better cutters for protein mass fingerprinting: preliminary findings.

Peptide-Mass Fingerprinting (PMF) encompasses a number of techniques for protein characterization which have as a first step the cleaving of target proteins by chemical or enzymatic reagents. Software systems exist which perform similar analyses. However, this is the first study which examines theoretically the effectiveness of the particular reagents for PMF. In this study, the task of PMF was to identify every sequence in a non-redundant protein database, via "in silico" digestion with theoretical proteases. From these experiments, some conclusions are drawn about the characteristics of better reagents and the experimental conditions which are more likely to be useful for PMF. The need for strongly non-redundant databases is also highlighted.

Amino Acid Sequence↗