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[Single nucleotide polymorphisms(SNPs)and SNP databases].

Along the rapid development of human genome sequencing project, the variation data of human DNA sequence has become more and more useful not only for studying the origin, evolution and the mechanisms of maintenance of genetic variability in human populations, but also for detection of genetic association in complex disease such as diabetes, obesity, hypertension, Alzheimer's disease, etc. In recent two years, the databases such as dbSNP, CGAP, HGBASE, JST and Go!Poly etc. to collect and exploit data of genomic polymorphisms mainly single nucleotide polymorphisms (SNPs) have been respectively established in the United States, European countries, Japan and China. This overview summarized the development and applications of those SNP databases and also discussed some issues regarding the potential improvement of accuracy of SNP data collected. China has one fifth population in the world. Therefore, development of the SNP database for Chinese populations is of importance in developing complete SNP databases of human genome and may also stimulate the further development of biomedical research and production in China.

Databases, Nucleic Acid↗

Competitive allele-specific short oligonucleotide hybridization (CASSOH) with enzyme-linked immunosorbent assay (ELISA) for the detection of pharmacogenetic single nucleotide polymorphisms (SNPs).

Individualization of drug therapy through genetic testing would maximize the effectiveness of medication and minimize its risks. Recent progress in genetic testing technologies has been remarkable, and they have been applied for the analysis of genetic polymorphisms that regulate drug responses. Clinical application of genetic information to individual health care requires simple and rapid identification of nucleotide changes in clinical settings. We previously reported a novel DNA diagnostic method for detecting single nucleotide polymorphisms (SNPs) using competitive allele-specific short oligonucleotide hybridization (CASSOH) with an immunochromatographic strip. We have developed the method further in order to incorporate an enzyme-linked immunosorbent assay (ELISA) into the final detection step; this enables multiple SNP detection. Special ELISA chips have been fabricated so that disposal of buffer waste is not required and handling procedures are minimized. This method (CASSOH-ELISA) has been successfully applied for the detection of clinically important SNPs in drug metabolism, such as N-acetyltransferase 2, NAT2*6 (590G>A) and NAT*7 (857G>A), and mitochondrial DNA (1555A>G). It would also facilitate point-of-care genetic testing for potentially diverse clinical applications.

Amino-Acid N-Acetyltransferase↗

Identification of single nucleotide polymorphisms (SNPs) and other sequence changes and estimation of nucleotide diversity in coding and flanking regions of the NMDAR1 receptor gene in schizophrenic patients.

Glutamatergic dysregulation has been hypothesized to play a role in schizophrenia. The N-methyl-D-aspartate (NMDA) type of glutamate receptor especially is of interest because, in addition to binding sites for glutamate and glycine, a necessary co-agonist, this receptor also contains noncompetitive binding sites for the psychotomimetics phencyclidine (PCP), MK-801, and ketamine. PCP-induced psychosis has been a useful disease model in that both the positive as well as the negative symptomatologies seen in schizophrenia are observed. Recently, a mouse deficient in expression of the NR1 subunit gene (NMDAR1) of the heteromeric receptor has been developed and shown to display aberrant behaviors, with reduced social and sexual interactions as well as increased stereotypic motor activity. In an extensive examination of the NMDAR1 gene in our laboratory in approximately 100 chronic schizophrenic patients, 28 unique sequence changes were identified, including eight single nucleotide polymorphisms (SNPs) in the 5' untranslated region (5'UTR), six SNPs in coding regions (cSNPs), eleven intronic SNPs, two intronic deletions of 7 and 30 bp, and an intronic microinsertion/deletion. With the exception of one previously reported cSNP, all of the identified changes were novel. The frequency of polymorphisms differed significantly by ethnicity and several appeared to be in linkage disequilibrium. None of the changes appeared likely to be of functional significance, thus suggesting that changes in the genomic NMDAR1 are unlikely to contribute to the etiology of schizophrenia. Estimates of nucleotide diversity are comparable to those observed in studies of other genes.

Asian People↗

Catalog of 46 single-nucleotide polymorphisms (SNPs) in the microsomal glutathione S-transferase 1 (MGST1) gene.

A major goal in our laboratory is to understand the role of common genetic variations among individual patients as regards susceptibility to common diseases and differences in therapeutic efficacy and/or side effects of drugs. As an addition to the high-density SNP (single-nucleotide polymorphism) maps of 12 glutathione S-transferase and related genes reported earlier, we provide here an SNP map of the microsomal glutathione S-transferase 1 (MGST1) gene. Among 48 healthy Japanese volunteers examined. we identified a total of 46 SNPs at this locus, 36 of which had not been reported before: 4 in the promoter region, 34 in introns, 3 in the 3' untranslated region, and 5 in the 3' flanking region. No SNP was found in 5'untranslated or coding regions. The ratio of transition to transversion was approximately 1.2:1. Among the 13 insertion-deletion polymorphisms was a 2-bp deletion in the coding region of MGST1 in DNA from one of the volunteers, which resulted in a frame-shift mutation. Since the gene product encoded by this mutant allele would lack the C-terminal half including the MAPEG (membrane-associated proteins in eicosanoid and glutathione metabolism) domain, MGST1 activity is likely to be reduced in the carrier's cells. The SNP map presented here adds to the archive of tools for studying complex genetic diseases, population migration patterns, and a variety of pharmacogenetic possibilities.

3' Untranslated Regions↗

The usefulness of single nucleotide polymorphisms (SNPs) for genetic epidemiological investigation of complex psychiatric diseases.

The genetic epidemiology of complex psychiatric diseases has become a much studied and very prospering field. It is widely believed that many genetic factors contribute to the various phenotypes and diseases, with overall contributions of a single factor being comparatively minor. The study of choice in such settings is the investigation of allelic association, which may be performed in a variety of ways. Here single nucleotide polymorphisms are an indispensable tool.

Gene Frequency↗

Candidate genes and single nucleotide polymorphisms (SNPs) in the study of human disease.

The genomic revolution has generated an extraordinary resource, the catalog of variation within the human genome, for investigating biological, evolutionary and medical questions. Together with new, more efficient platforms for high-throughput genotyping, it is possible to begin to dissect genetic contributions to complex trait diseases, specifically examining common variants, such as the single nucleotide polymorphism (SNP). At the same time, these tools will make it possible to identify determinants of disease with the expectation of eventually, tailoring therapies based upon specific profiles. However, a number of methodological, practical and ethical issues must be addressed before the analysis of genetic variation becomes a standard of clinical medicine. The currents of variation in human biology are reviewed here, with a specific emphasis on future challenges and directions.

Base Sequence↗

Single nucleotide polymorphisms (SNPs) within Bov-A2 SINE in the second intron of bovine and buffalo k-casein (CSN3) gene.

The genetic polymorphism of an entire Bov-A2 element located in the second intron of the buffalo and bovine k-casein (CSN3) gene was investigated by amplification and sequencing of PCR products. Single nucleotide polymorphisms were detected. A PCR-RFLP method was developed to detect an A or G mutation at position 605 of bovine Bov-A2 element which creates a BfaI polymorphic site. The frequencies of the B allele, with the BfaI site, were for 0.275, 0.775, 0.750, 0.975, respectively, for Italian Holstein Friesian, Grey Alpine, Friuli Red Pied and Reggio bovine breeds. The mutation rate (substitutions and deletions/insertions per nucleotide site per year) was 2.5 x 10(-9) for Bov-A2 sequences in the second intron of CSN3. The comparison with other Bov-A2 elements suggests that this retroelement might be an important source of single nucleotide polymorphism for analysis of Bovidae genomes.

Animals↗

Isolation and characterization of the human AKT1 gene, identification of 13 single nucleotide polymorphisms (SNPs), and their lack of association with Type II diabetes.

AIMS/HYPOTHESIS: AKT1, a serine/threonine protein kinase, is an important downstream target of the insulin-signalling pathway, with both anti-apoptotic and peripheral metabolic effects. Because impaired insulin signalling is a major hallmark of Type II (non-insulin-dependent) diabetes mellitus, we considered whether the AKT1 gene could be a candidate gene involved in susceptibility of this condition. To test this possibility, we isolated and characterized the human AKT1 gene. We also looked for single nucleotide polymorphisms in the gene and examined their association with Type II diabetes mellitus in the Ashkenazi Jewish population. METHODS: Human BAC/P1 genomic libraries were screened to isolate the AKT1 gene. To obtain structural information and the sequences of the exon-intron boundaries, BAC/P1 clones were directly sequenced. Identification of single nucleotide polymorphisms was done by polymerase chain reaction of each exon, followed by denaturing high performance liquid chromatography. Six single nucleotide polymorphisms were genotyped in Ashkenazi Jewish patients with Type II diabetes mellitus and in control subjects. RESULTS: The human AKT1 gene was at least 24.6 kb in length and comprised 14 exons. Altogether 13 putative intragenic single nucleotide polymorphisms, with minor-allele frequencies ranging from 0.011 to 0.354, were identified. The allelic and the genotypic frequencies of 6 single nucleotide polymorphisms were the same in diabetic patients and in control subjects. CONCLUSION/INTERPRETATION: The results of our studies show that the AKT1 gene is not a major contributor to susceptibility to Type II diabetes mellitus in Ashkenazi Jews.

Base Sequence↗

Expressed sequence tags (ESTs) and single nucleotide polymorphisms (SNPs): what large-scale sequencing projects can tell us about ADME.

To date over 800 complete genomes have been sequenced, with many more partially complete. Coupled with the large amount of mRNA transcript sequence data being produced from expression studies, there is now a daunting amount of information available to the research scientist. This review examines how this information may be best used, focusing on examples from sequences encoding absorption, distribution, metabolism and excretion (ADME)-related proteins in particular. Through the use of phylogenetic, splice variant and single nucleotide polymorphism (SNP) analysis, the review examines not only how insights into species-specific responses to drug exposure may be gained, but also how best to utilize this information to predict both individual human responses and the impact of population variance in response.

Alternative Splicing↗

A catalog of 106 single-nucleotide polymorphisms (SNPs) and 11 other types of variations in genes for transforming growth factor-beta1 (TGF-beta1) and its signaling pathway.

Transforming growth factor-beta1 (TGF-beta1) is a multifunctional cytokine that is produced in the platelet, bone, placenta, and other tissues. It acts as a growth inhibitor in many types of cells, and also mediates extracellular matrix production and immunosuppression. Mutations in the specific domain of its gene ( TGFB1) cause Camurati-Engelmann disease, a bone-sclerosing disorder, and those in other domains may be associated with osteoporosis. We identified 106 single-nucleotide polymorphisms and 11 other types of variations in TGFB1and six other genes. These genes were TGF-beta type I receptor gene (TGFBR1), TGF-beta type II receptor gene (TGFBR2), SMAD2 gene (SMAD2), SMAD3 gene (SMAD3), SMAD4 gene (SMAD4), and SMAD7 gene (SMAD7), all of which compose the TGF-beta1 signaling pathway. We also estimated allele frequencies of these DNA polymorphisms among 48 Japanese individuals. Our data will provide a useful resource for the study of disease susceptibility.

DNA Primers↗

Detection of novel single-nucleotide polymorphisms (SNPs) in the CYP21 gene and association analysis of two SNPs for CYP21 and ESR2 with litter size in a commercial sow population.

Altogether 129 F1 sows from a commercial sow farm with at least four litters were genotyped for the oestrogen receptor 2 gene (ESR2) and cytochrome P450 hydroxylase 21 gene (CYP21) and investigated for associations on the litter-size parameters: total number born and number born alive. Five novel polymorphisms were found in the 3'-untranslated region for the CYP21 gene. Genotype and allele frequencies for the CYP21 (position 3462G > A) single-nucleotide polymorphism (SNP) were 0.434 (GG), 0.504 (AG), 0.062 (AA) and 0.69 (G):0.31 (A), respectively. No association was found between this polymorphism and litter-size parameters. For the ESR2 gene, the SNP in exon 5 associated with an amino acid substitution MET (allele A) > VAL (allele G) was investigated. Only two genotypes were found leading to allele frequencies of 0.34 (A):0.66 (G). Only number born alive piglets were significantly increased for the AG genotype (p = 0.034) with 11.64 piglets per sow and litter in comparison with the GG genotype, leading to only 10.96 piglets per sow and litter. From these data, it can be concluded that the investigated SNP of the ESR2 gene is associated with the number of liveborn piglets in the commercial population considered, and hence could be useful in selection for litter size. Therefore, this gene should be investigated in additional populations.

Animals↗