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PubMed2005

Detection of Yersinia pestis DNA in two early medieval skeletal finds from Aschheim (Upper Bavaria, 6th century A.D.).

In the course of a molecular genetic investigation of a double inhumation, presumably a mother/child burial from Aschheim (Upper Bavaria, 6th century A.D.), which included analysis of mitochondrial DNA, molecular sexing, and polymorphic nuclear DNA, Yersinia pestis-specific DNA was detected. Molecular analyses were performed on DNA extracts obtained from two teeth of one skeleton and four teeth of the other. The use of the primer pair YP12D/YP11R (Raoult et al. [2000] Proc. Natl. Acad. Sci. 97:12800-12803), able to amplify part of the Y. pestis plasmid pPCP1 pla sequence, resulted in amplification products of the expected fragment size. Using BLASTN 2.2.2, the sequences of these amplification products shared 100% identity with that of the modern Y. pestis pla sequence in GenBank, with the exception of one amplification product which revealed a single base substitution. The application of a "suicide PCR" with the independent primer pair YP11D/YP10R (Raoult et al. [2000] Proc. Natl. Acad. Sci. 97:12800-12803) resulted in amplification products which shared a 96-98% homology with that of the modern Y. pestis pla sequence in GenBank. The observed deviations were presumably due to miscoding lesions in the template DNA. No modern Y. pestis DNA was introduced into the institute, and thus no positive controls were carried along. All extraction and PCR controls remained negative. The identification of Y. pestis-specific DNA sequences in these two skeletons, buried in the second half of the 6th century A.D., constitutes molecularly supported evidence for the presence of Y. pestis, the causative agent of plague, during the first pandemic recorded.

Apolipoproteins E↗
PubMed2003

Surprising roles of electrostatic interactions in DNA-ligand complexes.

The positions of cations in x-ray structures are modulated by sequence, conformation, and ligand interactions. The goal here is to use x-ray diffraction to help resolve structural and thermodynamic roles of specifically localized cations in DNA-anthracycline complexes. We describe a 1.34 A resolution structure of a CGATCG(2)-adriamycin(2) complex obtained from crystals grown in the presence of thallium (I) ions. Tl(+) can substitute for biological monovalent cations, but is readily detected by distinctive x-ray scattering, obviating analysis of subtle differences in coordination geometry and x-ray scattering of water, sodium, potassium, and ammonium. Six localized Tl(+) sites are observable adjacent to each CGATCG(2)-adriamycin(2) complex. Each of these localized monovalent cations are found within the G-tract major groove of the intercalated DNA-drug complex. Adriamycin appears to be designed by nature to interact favorably with the electrostatic landscape of DNA, and to conserve the distribution of localized cationic charge. Localized inorganic cations in the major groove are conserved upon binding of adriamycin. In the minor groove, inorganic cations are substituted by a cationic functional group of adriamycin. This partitioning of cationic charge by adriamycin into the major groove of CG base pairs and the minor groove of AT base pairs may be a general feature of sequence-specific DNA-small molecule interactions and a potentially useful important factor in ligand design.

Antibiotics, Antineoplastic↗
PubMed2003

Pattern identification and classification in gene expression data using an autoassociative neural network model.

The application of DNA microarray technology for analysis of gene expression creates enormous opportunities to accelerate the pace in understanding living systems and identification of target genes and pathways for drug development and therapeutic intervention. Parallel monitoring of the expression profiles of thousands of genes seems particularly promising for a deeper understanding of cancer biology and the identification of molecular signatures supporting the histological classification schemes of neoplastic specimens. However, the increasing volume of data generated by microarray experiments poses the challenge of developing equally efficient methods and analysis procedures to extract, interpret, and upgrade the information content of these databases. Herein, a computational procedure for pattern identification, feature extraction, and classification of gene expression data through the analysis of an autoassociative neural network model is described. The identified patterns and features contain critical information about gene-phenotype relationships observed during changes in cell physiology. They represent a rational and dimensionally reduced base for understanding the basic biology of the onset of diseases, defining targets of therapeutic intervention, and developing diagnostic tools for the identification and classification of pathological states. The proposed method has been tested on two different microarray datasets-Golub's analysis of acute human leukemia [Golub et al. (1999) Science 286:531-537], and the human colon adenocarcinoma study presented by Alon et al. [1999; Proc Natl Acad Sci USA 97:10101-10106]. The analysis of the neural network internal structure allows the identification of specific phenotype markers and the extraction of peculiar associations among genes and physiological states. At the same time, the neural network outputs provide assignment to multiple classes, such as different pathological conditions or tissue samples, for previously unseen instances.

Adenocarcinoma↗
PubMed2006

Investigation of de novo totally random biosequences, Part III: RNA Foster: A novel assay to investigate RNA folding structural properties.

Fold is essential to RNA properties, and, in particular, its thermodynamic stability can be used to monitor RNA-protein or RNA-ligand interactions, and to engineer RNA with novel or improved properties. While clearly valuable, experimental determination of RNA folding stability by traditional biophysical techniques requires substantial amounts of pure sample and rather expensive equipment. In this paper, we report a new, simple approach to the determination of RNA folding stability by coupling enzymatic digestion and temperature denaturation. The assay, named RNA folding stability Test (RNA Foster), is designed to probe the fraction of folded RNA (f(fold)) in an equilibrium mixture of folded and unfolded ones as a function of temperature. The simplicity of RNA Foster suggests that it can easily be scaled up for high-throughput studies of RNA folding stability both in basic and applied research.

Base Sequence↗
PubMed2002

Aligning experimental design with bioinformatics analysis to meet discovery research objectives.

The utility of genomic technology and bioinformatic analytical support to provide new and needed insight into the molecular basis of disease, development, and diversity continues to grow as more research model systems and populations are investigated. Yet deriving results that meet a specific set of research objectives requires aligning or coordinating the design of the experiment, the laboratory techniques, and the data analysis. The following paragraphs describe several important interdependent factors that need to be considered to generate high quality data from the microarray platform. These factors include aligning oligonucleotide probe design with the sample labeling strategy if oligonucleotide probes are employed, recognizing that compromises are inherent in different sample procurement methods, normalizing 2-color microarray raw data, and distinguishing the difference between gene clustering and sample clustering. These factors do not represent an exhaustive list of technical variables in microarray-based research, but this list highlights those variables that span both experimental execution and data analysis.

Computational Biology↗
PubMed2005

Genomic resources for chicken.

The recent sequencing and draft assembly of a chicken genome has provided biologists with an invaluable research tool that complements a growing list of additional avian genomic resources. For many researchers, finding and using these resources is challenging, because information is presented through an increasing number of Web sites and browser navigation frequently requires specific knowledge and expertise. This primer provides an overview of online genomic resources for the chicken, including the Ensembl, UCSC, and NCBI annotated chicken genome browsers; expressed sequence tag and in situ hybridization databases; and sources for microarrays, cDNAs, and bacterial artificial chromosomes (BACs). Several short tutorials oriented toward the biologist with limited bioinformatics skills outline how to retrieve several types of commonly needed information and reagents.

Animals↗
PubMed2004

A high-performance multilane microdevice system designed for the DNA forensics laboratory.

We report preliminary testing of "GeneTrack", an instrument designed for the specific application of multiplexed short tandem repeat (STR) DNA analysis. The system supports a glass microdevice with 16 lanes of 20 cm effective length and double-T cross injectors. A high-speed galvanometer-scanned four-color detector was specially designed to accommodate the high elution rates on the microdevice. All aspects of the system were carefully matched to practical crime lab requirements for rapid reproducible analysis of crime-scene DNA evidence in conjunction with the United States DNA database (CODIS). Statistically significant studies demonstrate that an absolute, three-sigma, peak accuracy of 0.4-0.9 base pair (bp) can be achieved for the CODIS 13-locus multiplex, utilizing a single channel per sample. Only 0.5 microL of PCR product is needed per lane, a significant reduction in the consumption of costly chemicals in comparison to commercial capillary machines. The instrument is also designed to address problems in temperature-dependent decalibration and environmental sensitivity, which are weaknesses of the commercial capillary machines for the forensics application.

DNA↗
PubMed2004

Evaluation and validation of the ABI 3700, ABI 3100, and the MegaBACE 1000 capillary array electrophoresis instruments for use with short tandem repeat microsatellite typing in a forensic environment.

The demand for high-throughput DNA profiling has increased with the introduction of national DNA databases and has led to the development of automated methods of short tandem repeat (STR) profile production; however, a potential bottleneck still exists at the gel electrophoresis stage. Capillary electrophoresis sequencers capable of processing 96 samples with considerably reduced manual intervention are now available. In this paper, we compare the ABI Prism 377 slab-gel sequencer currently used by the Forensic Science Service with three leading capillary array electrophoresis instruments: the ABI Prism 3700, the Amersham MegaBACE 1000 and the 16-capillary ABI Prism 3100. We describe the experiments used to evaluate and validate these platforms for forensic use with the STR multiplex Ampf/STR SGMplus [1, 2], along with comparative data from the ABI Prism 377 sequencer.

Databases, Nucleic Acid↗
PubMed2005

The interactive online SKY/M-FISH & CGH database and the Entrez cancer chromosomes search database: linkage of chromosomal aberrations with the genome sequence.

To catalog data on chromosomal aberrations in cancer derived from emerging molecular cytogenetic techniques and to integrate these data with genome maps, we have established two resources, the NCI and NCBI SKY/M-FISH & CGH Database and the Cancer Chromosomes database. The goal of the former is to allow investigators to submit and analyze clinical and research cytogenetic data. It contains a karyotype parser tool, which automatically converts the ISCN short-form karyotype into an internal representation displayed in detailed form and as a colored ideogram with band overlay, and also has a tool to compare CGH profiles from multiple cases. The Cancer Chromosomes database integrates the SKY/M-FISH & CGH Database with the Mitelman Database of Chromosome Aberrations in Cancer and the Recurrent Chromosome Aberrations in Cancer database. These three datasets can now be searched seamlessly by use of the Entrez search and retrieval system for chromosome aberrations, clinical data, and reference citations. Common diagnoses, anatomic sites, chromosome breakpoints, junctions, numerical and structural abnormalities, and bands gained and lost among selected cases can be compared by use of the "similarity" report. Because the model used for CGH data is a subset of the karyotype data, it is now possible to examine the similarities between CGH results and karyotypes directly. All chromosomal bands are directly linked to the Entrez Map Viewer database, providing integration of cytogenetic data with the sequence assembly. These resources, developed as a part of the Cancer Chromosome Aberration Project (CCAP) initiative, aid the search for new cancer-associated genes and foster insights into the causes and consequences of genetic alterations in cancer.

Base Sequence↗
PubMed2005

Estimating haplotype-disease associations with pooled genotype data.

The genetic dissection of complex human diseases requires large-scale association studies which explore the population associations between genetic variants and disease phenotypes. DNA pooling can substantially reduce the cost of genotyping assays in these studies, and thus enables one to examine a large number of genetic variants on a large number of subjects. The availability of pooled genotype data instead of individual data poses considerable challenges in the statistical inference, especially in the haplotype-based analysis because of increased phase uncertainty. Here we present a general likelihood-based approach to making inferences about haplotype-disease associations based on possibly pooled DNA data. We consider cohort and case-control studies of unrelated subjects, and allow arbitrary and unequal pool sizes. The phenotype can be discrete or continuous, univariate or multivariate. The effects of haplotypes on disease phenotypes are formulated through flexible regression models, which allow a variety of genetic hypotheses and gene-environment interactions. We construct appropriate likelihood functions for various designs and phenotypes, accommodating Hardy-Weinberg disequilibrium. The corresponding maximum likelihood estimators are approximately unbiased, normally distributed, and statistically efficient. We develop simple and efficient numerical algorithms for calculating the maximum likelihood estimators and their variances, and implement these algorithms in a freely available computer program. We assess the performance of the proposed methods through simulation studies, and provide an application to the Finland-United States Investigation of NIDDM Genetics Study. The results show that DNA pooling is highly efficient in studying haplotype-disease associations. As a by-product, this work provides valid and efficient methods for estimating haplotype-disease associations with unpooled DNA samples.

Algorithms↗
PubMed2002

New insights into ocular albinism type 1 (OA1): Mutations and polymorphisms of the OA1 gene.

Albinism ocular type 1 (OA1) is an X-linked type of albinism that mainly effects pigment production in the eye, resulting in hypopigmentation of the retina, nystagmus, strabismus, foveal hypoplasia, abnormal crossing of the optic fibers, and reduced visual acuity. The OA1 gene is located on chromosome Xp22.32 and the coding sequence is divided into nine exons. The protein is an integral transmembrane protein that has weak similarities to G protein-coupled receptors. A total of 25 missense, two nonsense, nine frameshift, and five splicing mutations have been reported in the OA1 gene associated with OA1. There are also several deletions of some or all exons of the OA1 gene with deletions of exon 2 resulting from unequal crossing-over, due to flanking Alu repeats. Mutation and polymorphism data on this gene is available from the International Albinism Center - Albinism Database web site (http://www.cbc.umn.edu/tad).

Albinism, Ocular↗
PubMed2002

Data mining of public SNP databases for the selection of intragenic SNPs.

Different strategies to search public single nucleotide polymorphism (SNP) databases for intragenic SNPs were evaluated. First, we assembled a strategy to annotate SNPs onto candidate genes based on a BLAST search of public SNP databases (Intragenic SNP Annotation by BLAST, ISAB). Only BLAST hits that complied with stringent criteria according to 1) percentage identity (minimum 98%), 2) BLAST hit length (the hit covers at least 98% of the length of the SNP entry in the database, or the hit is longer than 250 base pairs), and 3) location in non-repetitive DNA, were considered as valid SNPs. We assessed the intragenic context and redundancy of these SNPs, and demonstrated that the SNP content of the dbSNP and HGBASE/HGVbase databases are highly complementary but also overlap significantly. Second, we assessed the validity of intragenic SNP annotation available on the dbSNP and HGVbase websites by comparison with the results of the ISAB strategy. Only a minority of all annotated SNPs was found in common between the respective public SNP database websites and the ISAB annotation strategy. A detailed analysis was performed aiming to explain this discrepancy. As a conclusion, we recommend the application of an independent strategy (such as ISAB) to annotate intragenic SNPs, complementary to the annotation provided at the dbSNP and HGVbase websites. Such an approach might be useful in the selection process of intragenic SNPs for genotyping in genetic studies. Hum Mutat 20:162-173, 2002.

DNA↗
PubMed2002

The human SHOX mutation database.

The human SHOX database has recently been established to provide clinicians and scientists access to a central source of information about all known SHOX mutations associated with short stature phenotypes such as idiopathic short stature, Lèri-Weill dyschondrosteosis, Langer syndrome, and Turner syndrome. So far, the database contains 29 unique intragenic mutations of the SHOX gene. These mutations were detected in a total of 39 patients from different families. Fourteen of these mutations have been found from the SHOX research group at the Institute of Human Genetics in Heidelberg, Germany; 25 mutations are from data reported in the literature. Not included in this database are complete SHOX gene deletions which represent the majority of all detectable SHOX mutations [Rappold et al., 2002]. The database is accessible via the website www.shox.uni-hd.de. It contains general information about the SHOX gene, and allows remote users to search the data and to submit new mutations to the database.

Base Sequence↗
PubMed2004

Allelic genes of blood group antigens: a source of human mutations and cSNPs documented in the Blood Group Antigen Gene Mutation Database.

In this report, we analyze data assembled in the Blood Group Antigen Gene Mutation Database (www.bioc.aecom.yu.edu/bgmut/index.htm), which describes sequence information on human genes associated with expression of the various serologically-determined blood group phenotypes. The database documents 38 genetic loci and a total of 624 alleles that together encode a large repertoire of proteins and constitute 27 serologically-defined blood group systems. Analysis of sequence variation patterns across alleles of a number of genes is focused on their molecular profiles, including mutational sites and recurrence, patterns of gene rearrangements in duplicated gene families, correlation of predicted location of epitopes in extracellular loops with sites of alterations, and effects of mutations on protein expression. That information, and the relative ease of identifying individuals bearing variant alleles, has led to the proposal that genes encoding blood group antigens are an important and unique resource for studies of human DNA variation. Another focus is on mutations in regions that encode the antigenic epitopes and on their occurrence in world populations. These mutations may be viewed as coding single nucleotide polymorphisms (cSNPs). We propose that one group of these cSNPs, which are known to occur with significant frequency in all world populations, could serve as well-validated genetic markers. In addition, specific mutations in a number of "low incidence" and rare alleles could serve as cSNPs specific for a given population. The allelic frequencies of these mutations and knowledge of their world-wide occurrence add a valuable dataset to the existing cSNP pools documented in SNP databases.

Alleles↗
PubMed2001

10th International Hugo mutation database initiative meeting, 19 April 2001, Edinburgh, Scotland.

The 10th International Mutation Database Initiative Meeting was held on April 19, 2001, in conjunction with the annual Human Genome Meeting in Edinburgh, Scotland. Key points of the meeting are described here. The BiSC WayStation was presented as an operational, viable beginning to the solution for the lack of centralized variation collection structures, with a number of possibilities, notably the BiSC Central Database and HGBASE, as candidates for storing the data. Exploration of new avenues of funding for this project, affiliation with Wiley-Liss, and the establishment of the Mutation Database Initiative (MDI) as a society were also discussed.

Databases, Nucleic Acid↗
PubMed2001

Go!Poly: A gene-oriented polymorphism database.

Human genome polymorphisms play a key role in defining the molecular basis of phenotypic differences between individuals in aspects such as disease susceptibility and drug responses. The database requirements for supporting the study of human genetic variation have been well recognized. In order to meet these needs, several generalized databases have been built. However, it is still hard for users to find gene-related variation data from these huge and sophisticated databases. In its role as a gene-oriented directory of polymorphism data, Go!Poly (Gene Oriented Polymorphism Database; http://61.139.84.5/gopoly/) utilizes two new highly curated and non-redundant resources, LocusLink (http://www.ncbi.nlm.nih.gov/LocusLink/) and RefSeq (http://www.ncbi.nlm.nih.gov/LocusLink/refseq.html), as the standard for identifying and positioning nucleotide variations. As a generalized polymorphism database, Go!Poly extracts human gene-linked sequence variations of all common types (SNP, insertion-deletion, simple tandem repeat, and complex nucleotides variations) from various public resources including scientific journals and internet resources, such as HGBASE (http://hgbase.cgr.ki.se) and dbSNP (http://www.ncbi.nlm.nih.gov/SNP/). The polymorphism data are then categorized into different gene loci, and the reference sequences given by LocusLink are used as positioning references. Through close integration with LocusLink, Go!Poly also provides facilitated connections among sequence data, gene name, and related biological information. This feature also makes Go!Poly easy to search and navigate. Future automated annotations and internal consistency checking may also benefit from this. Extensive efforts are being taken to make the polymorphism information generated by the Chinese scientific community available from this resource.

China↗
PubMed2004

Approaches for analyzing human mutations and nucleotide sequence variation: a report from the Seventh International Mutation Detection meeting, 2003.

The Seventh International Symposium on Mutations in the Human Genome, Mutation Detection 2003, was held during 2-6 July 2003 in Palm Cove near Cairns, Australia. The meeting was organized under the auspices of the Human Genome Organisation (HUGO) as a satellite meeting of the International World Congress of Genetics, held in Melbourne the following week. Meeting participants reported on advances in mutation detection technologies, including advances in high-throughput detection systems for SNP genotyping applicable to the international haplotype mapping project (HapMap); and bioinformatics tools, including databases for handling and processing growing amounts of genome variation data. This meeting report summarizes the presentations and cites related articles from the special issue of Human Mutation (Volume 23#5, May 2004; available online at www.wiley.com/humanmutation).

Base Sequence↗