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Results for “Polymorphism, Restriction Fragment Length”

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PubMed1991

HLA class II antigens and DNA restriction fragment length polymorphism in myasthenia gravis in Japan.

Human leukocyte phenotypes and genes in the HLA class II regions were studied in 46 Japanese patients with myasthenia gravis. When the HLA phenotypes of the patients with myasthenia gravis were compared with the controls, an increased frequency of HLA-DRw53 was observed in females less than 30 years of age. The genomic DNAs of the HLA-DRw53-positive patients and DRw53-positive controls were analyzed by using four complementary DNA probes for HLA class II genes. With DQB complementary DNA as the probe, a higher incidence of the 6.5-kb or 8.2-kb BamHI fragment was observed in the patients (76.0%) compared with the controls (19.0%). In contrast, no significant difference was observed between patients and controls when complementary DNAs for DRB, DQA, and DPB were used as probes. These results indicate that the genetic background of Japanese females with early-onset myasthenia gravis is different from other patients with myasthenia gravis, and that DQB genes can greatly influence the onset of myasthenia gravis.

Adolescent↗

PubMed1990

Characterization of two hybrid C4 allotypes (C4A12 and C4B3) by electrophoretic, serological and restriction fragment length polymorphism analyses.

Informative pedigree analysis of two rare C4 allotypes is reported. One proband was C4A deficient as a consequence of having one haplotype with a deleted C4A gene, and the second haplotype with two C4B genes--one encoding the common C4B*1 and one encoding a unique hybrid gene product C4B*3. C4B*3 had approximately normal C4B hemolytic activity, a single alpha-chain of MR 94,000 by SDS-PAGE but was positive for Rg:1,2 by hemagglutination inhibition (HAI) and for Rg:1 by Western blotting. The hybrid nature was confirmed by RFLP analysis with a Rg:1-associated fragment by Eco0109 digestion but no C4A-associated fragments by N1aIV digestion were identified. A gene conversion at Locus I which included just the C4 isotype region could explain the structure of C4B*3. The second pedigree had a Rodgers negative C4A*12 allotype. This C4A gene, which segregated with a single 7.0 kb TaqI fragment, encoded a C4A alpha-chain, which was negative for Rg:1 epitope. The affected haplotype lacked the Rg:1-associated fragment by Eco0109 digestion yet had the C4A specific N1aIV digestion fragment. These studies successfully employed RFLP analyses to confirm serologic and electrophoretic observations.

Adolescent↗

PubMed1995

Differentiation of epidemic-associated strains of Listeria monocytogenes by restriction fragment length polymorphism in a gene region essential for growth at low temperatures (4 degrees C).

The growth of Listeria monocytogenes in food stored in the cold has often been implicated in outbreaks of listeriosis. Many subtyping schemes have suggested that epidemic-associated strains belong to a unique genetic group. It has not yet been possible, however, to identify molecular or bacteriologic markers unique to epidemic-associated strains. Recently we cloned three genes of L. monocytogenes, ltrA, ltrB, and ltrC, which are essential for growth at low temperatures (4 degrees C). The use of a 1.2-kb PstI fragment derived from ltrB as a probe in Southern blots of HindIII-digested DNA revealed three hybridization patterns: the first (a 5.0-kb band) was observed in strains of serotypes 4b, 1/2b, and 3b; the second (a 3.1-kb band) was seen in strains of serotypes 1/2a, 3a, 1/2c, and 3c; and the third (a 9.5-kb band) was characteristic of epidemic-associated serotype 4b strains. These and other data suggest that probes derived from this gene region that is essential for growth at low temperatures can be useful molecular tools for the subtyping of strains implicated in food-borne listeriosis.

Base Sequence↗

PubMed1994

Mitochondrial DNA restriction fragment length polymorphisms in field isolates of the Aspergillus niger aggregate.

The mitochondrial DNAs (mtDNAs) and the ribosomal repeat unit (ribosomal DNA, rDNA) of black Aspergillus isolates collected in various parts of the world were examined. Wide-ranging mtDNA variation was observed in natural populations of the Aspergillus niger aggregate. Most isolates were classifiable as A. niger or Aspergillus tubingensis according to their rDNA and mtDNA patterns. The mtDNA variation was distributed unevenly in the populations studied. The mtDNAs of most of the isolates collected in Australia were of the A. tubingensis type, with an unexpectedly high degree of variation, while the rDNA of these isolates exhibited the same A. tubingensis pattern as that of isolates from other locations. Some other local populations displayed very little polymorphism in their mtDNA and rDNA. Hybridization experiments in which cloned A. niger and Aspergillus nidulans mtDNA fragments were used revealed that the two main mtDNA groups corresponding to A. niger and A. tubingensis are more distantly related than concluded earlier. Six of the 13 Brazilian isolates examined exhibited mtDNA and rDNA types different from those of all the other strains and could not be classified into the above species. Classical taxonomic examination of these strains is in progress.

Aspergillus↗

PubMed1990

Association between a T cell receptor restriction fragment length polymorphism and systemic lupus erythematosus.

The present study was designed to test the possibility that T cell receptor genes are associated/linked to those involved in systemic lupus erythematosus (SLE). Genomic DNA was isolated from 31 unrelated Caucasian SLE patients, 34 unrelated Caucasian normals, 5 multiplex American Caucasian SLE families, 9 multiplex Mexican SLE families, and 13 unrelated Mexican normals. The DNA was digested with Pst I, electrophoresed, and transferred to membranes by the Southern blot method. The blots were probed with a cDNA probe for the alpha chain of the T cell receptor. 13 polymorphic RFLP patterns were recognized. 1.3- and 3.0-kb band pairs were observed in 15 of 31 of American Caucasian patients and 4 of 34 American Caucasian controls (chi square, 8.81; P less than 0.002; relative risk, 7); there was no association of any RFLP pattern with Mexican SLE. The cDNA probe was cut with Rsa I, EcoR I, and Ava II into fragments corresponding to the V, J, C, and 3'UT regions. Only the fragment corresponding to the constant region reacted with the 1.3/3.0-kb band pair. These observations suggest that a genetic marker of the constant region of the alpha chain of the T cell receptor is associated with genes involved in SLE.

Autoantibodies↗

PubMed2004

Detection of isolated tumor cells by polymerase chain reaction-restriction fragment length polymorphism for K-ras mutations in tissue samples of 199 colorectal cancer patients.

The aim of this study was to identify K-ras mutations as marker for isolated tumor cells in liver, lymph node, and bone marrow specimens of colorectal cancer patients. To detect these, a PCR-RFLP assay was used with a sensitivity exceeding that of routine histopathology by at least 1 order of magnitude. In addition, the ratio of mutated versus wild-type alleles was determined by an internal standard. Of 199 patients, 74 (37.5%) were found to bear a K-ras-positive tumor. Of these, 60 (81%) were mutated in codon 12 and 14 (19%) in codon 13 (P < 0.001). In addition, 14 organs were found K-ras positive, 13 of which were from 12 patients with a K-ras-positive tumor (16%) and 1 from a patient with a K-ras-negative tumor (0.8%). Eight patients exhibited liver involvement and 6 showed lymph node involvement. Remarkably, no bone marrow specimen was found K-ras positive (P < 0.017 versus liver involvement). Sequence analysis of tumor DNA revealed that GGT (Gly) was replaced by GAT (Asp; 35%), GTT (Val; 32%), AGT (Ser; 13%), GCT (Ala; 10%), TGT (Cys; 8%), and CGT (Arg; 2%) for codon 12, and by GAC (Asp) as the only type of mutation for codon 13. In colorectal carcinomas the ratio of K-ras mutated versus wild-type alleles ranged over 4 orders of magnitude (10(0)-10(-4), median: 10(-2)) and was correlated with both, residual tumor load (R1/2; P = 0.028) and distant metastasis (M1; P = 0.057). These results show that detection of K-ras mutated alleles by PCR-RFLP in patients with colorectal carcinoma may aid in the identification of isolated tumor cells. High ratios of K-ras alleles were correlated with certain negative prognostic parameters (R,M). In accord with its function as a primary filter for colorectal carcinoma cells, the liver was more often contaminated with K-ras-positive cells than bone marrow.

Adult↗

PubMed1992

Restriction fragment length polymorphism (RFLP) analysis provides evidence for a high degree of homology of mitochondrial DNAs from rat hepatomas versus normal rat livers.

Where differences have been reported between tumor and normal mitochondrial DNA (mtDNA), they have generally involved limited modifications of the genome (Taira et al., Nucleic Acids Res. 11:1635, 1983; Shay and Werbin, Mutat. Res. 186:149, 1987). However, Corral et al. (Nucleic Acids Res. 16:10935, 1988; 17:5191, 1989) observed recombination between cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 6 (ND6), two genes normally on opposite sides of the circular mitochondrial genome. In rat hepatoma mtDNA COI and ND6 were reported to be separated by only 230 base pairs (Corral et al., 1988, 1989). We have performed RFLP analysis on mtDNA from normal rat livers and rat hepatomas, using COI and ND6 probes. Additional experiments compared end-labeled DNA fragments produced by EcoRI and HindIII digestion of mtDNA. These studies failed to provide any evidence for genetic recombination in rat hepatoma mtDNA, even in the same cell line used by Corral et al. Rather, they support the conclusion that mtDNA from tumor and normal tissues exhibits a low degree of heterogeneity.

Animals↗

PubMed1994

Germline complexity, restriction fragment length polymorphism, and coding region sequences of the human VH7 gene family identified with family-specific FR3 segment oligonucleotides.

We have used the most family-specific gene segment, the 5'-end of framework 3 (FR3) to study the germline complexity and coding region sequences of the recently described human VH7 gene family. Because of the high degree of 5' sequence homology between members of the VH7 and VH1 families, full-length coding region probes are unable to distinguish between the two groups. Hybridization with a VH7 coding region probe to EcoRI digested genomic DNA revealed 12 fragments. Many of these hybridizing fragments were also identified with a full length VH1 coding sequence probe. However, examination of the same DNA samples with a VH7 family specific oligonucleotide, encompassing the 5'-end of the FR3 segment, greatly reduced hybridization complexity yielding only four fragments which included one polymorphic band of molecular weight 7.4 kb. The VH7 specific FR3 oligonucleotide was also used under conditions of moderate stringency to isolate VH7 clones from PCR-amplified genomic DNA libraries derived from six unrelated individuals. All clones isolated contained members of the VH7 family. Six sequences were obtained. Gene 7A.4, seen in all individuals, is identical to the previously described germline V1-4.1b gene other than G-C substitutions at nucleotides 253 and 254. Five distinct pseudogenes were also identified. Stop codons were confined to frameworks 2 and 3. Previously described expressed VH7 genes from cord blood, normal adults and two rheumatoid factors are > 96% homologous to gene 7A.4.

Amino Acid Sequence↗

PubMed1986

Huntington disease-linked restriction fragment length polymorphism localized within band p16.1 of chromosome 4 by in situ hybridization.

A 5.5-kilobase (kb) single sequence DNA fragment (G8) reveals the DNA polymorphic locus D4S10 on Southern blot analysis. This locus is closely linked to Huntington disease and has been mapped to chromosome 4 short arm using human-mouse somatic cell hybrids, and specifically to chromosome 4 band p16 using DNA from individuals with deletions of chromosome 4 short arm who exhibit Wolf-Hirschhorn syndrome. With in situ hybridization techniques, we have confirmed the location of D4S10 on chromosome 4 and further localized it within band p16 utilizing five patients, four with overlapping chromosome 4 short-arm aberrations. The DNA segment G8 was hybridized to the mataphase chromosomes of the five patients. Two of them have different interstitial deletions of one of the chromosome 4 short arms (TA and BA), two have different chromosome 4 short-arm terminal deletions (RG and DQ), and one has a normal male karyotype. By noting the presence or absence of hybridization to the partially deleted chromosomes with known precise breakpoints, we were able to more accurately localize probe G8 to the distal half of band p16.1 of chromosome 4.

Chromosome Banding↗

PubMed2004

[Relations between clinical subtypes of Mycobacterium avium pulmonary disease and polyclonal infections detected by IS1245 based restriction fragment length polymorphism analysis].

INTRODUCTION: The epidemiology of Mycobacterium avium-intracellulare (MAC) infections has not been completely defined. Recently some reports presented polyclonal MAC infections. The purpose of this study was to reveal the clonal diversity of Mycobacterium avium isolates and the relation between clinical subtype of lung disease and polyclonal infection. METHODS: We categorized pulmonary Mycobacterium avium infection to three clinical subtypes, tuberculosis like type, bronchiectasis with preexisting tuberculosis type and nodular bronchiectasis type. Mycobacterium avium isolates of 11 patients were studied for their heterogeneity using IS1245 based RFLP analysis. The insertion sequence IS1245 is repetitive element identified only in Mycobacterium avium. Standard method of IS1245 based RFLP analysis has been proposed as a suitable technique for typing of Mycobacterium avium isolates for epidemiological and taxonomic studies. At least three distinct colonies were subcultured to single clone. The subclones of the isolates were analyzed by IS1245 based RFLP technique and some subclones were also examined by antimicrobial susceptibility test. RESULTS: Two of three patients of tuberculosis like type were considered to be monoclonal infection because only a single genotype was identified. And only one of four patients of bronchiectasis with preexisting tuberculosis type was considered to be polyclonal infection despite of long-term observation. Although isolates were collected in two or more occasions in clinical course over one year period, only a single genotype was observed in two patients. In contrast, three of four patients of nodular bronchiectasis type had multiple genotypes. Isolates recovered from patients with monoclonal infection pattern following long-term treatment with clarithromycin monotherapy became resistant to clarithromycin. In contrast, three strains derived from one nodular bronchiectasis patient were susceptible to clarithromycin despite of long-term chemotherapy including clarithromycin. The susceptibility patterns of the other drugs were also apparently different. Strain conversion due to repeated polyclonal infection was considered. These results of the antimicrobial susceptibility test supported clonal diversity of the Mycobacterium avium infection. DISCUSSION: IS1245 based RFLP analysis possesses a discriminatory power between the isolates on clonal level. This study demonstrates that polyclonal infections are common in nodular bronchiectasis type and monoclonal infections are common in tuberculosis like type and bronchiectasis with preexisting tuberculosis type. And not only simultaneous polyclonal infection but also repeated polyclonal infection were observed in a nodular bronchiectasis type patient. Drug susceptibility test showed long-term chemotherapy including clarithromycin could change the susceptibility of clarithromycin to resistant in patients with monoclonal infection. In contrast patients with repeated polyclonal infection pattern would avoid drug resistance because of strain conversion. This multiple susceptibility patterns identified in this study would not have been detected by the standard susceptibility test without subculture. And we also need the treatment strategy considering the polyclonal infection. CONCLUSIONS: Polyclonal infections are considered to be common in pulmonary Mycobacterium avium infection, especially nodular bronchiectasis type. Clonal diversity of Mycobacterium avium infection is an important factor to perform chemotherapy and drug susceptibility test.

Adolescent↗

PubMed2002

PCR restriction fragment length polymorphism in detection of YMDD variants of viral polymerase in hepatitis B virus patients treated with lamivudine.

OBJECTIVE: To analyse the emergence of YMDD motif (tyrosine-methionine-aspartate-aspartate) variants in patients with hepatitis B treated with lamivudine. METHODS: The amino acid substitution from methionine or isoleucine at the YMDD motif at the HBV polymerase gene is a main mutation resistant to lamivudine treatment. Generated from a fragment of domain C of the polymerase gene, patients' HBV DNA, which had been positive previously became positive again ever since it had been negative during lamivudine therapy. Variants were detected by cleavage of the products of the three PCRs with following enzymes: FokI, SspI, Alw441. The results of PCR-RELP were analysed by 8.4% polypropylene acidemide gel electrophoresis. PCR-RFLP assay was compared to direct sequencing. RESULTS: HBV DNA was positive again in 33 patients and positive for one year in 2 patients. YMDD variants were detected in serum 14 of 35 patients, YIDD variants in 4, YVDD variants in 6, and YI/MDD variants in 1; all were in concordance with the results of direct sequencing. The samples of other 3 patients showed YI/VDD mutations, as shown by direct sequencing. The results of PCR-RFLP assay of the mixed sera of YIDD and YVDD variants were similar to those sera of YI/VDD variants. CONCLUSION: PCR-RFLP is suitable for rapid detection of YMDD variants of viral polymerase in hepatitis B virus patients treated with lamivudine.

Adolescent↗

PubMed1994

TaqI restriction fragment length polymorphisms for growth hormone in bovine breeds and their association with quantitative traits.

The objectives of the present study were (1) to reveal GH-TaqI RFLPs in different bovine breeds and (2) to look for association between quantitative traits and GH-TaqI RFLPs in bulls highly selected for growth and meat production. Blood was sampled from 269 Holstein heifers, 48 Italian and 45 Hungarian Simmental heifers, 30 Normande heifers and 41 bulls and 13 heifers of the double-muscled Belgian White Blue breed. Bulls were weighed from 7 until 13 months of age and the average daily gain, the feed efficiency, the height and the phenotypic index were determined at the end of the experiment. GH-TaqI RFLPs revealed 4 DNA fragments of 6 (A), 5.2 (B), 4.4 (C) and 4.2 (D) kbp. The distribution of genotypes was different between Normande and the other breeds (P < 0.001) and between Belgian White Blue and Holstein (P < 0.001) or Hungarian Simmental breed (P < 0.005). The Normande heifers were also characterized by a high frequency of the AB genotype (53%) compared with other experimental breeds (range values: 7-24%). In the statistical analysis of the relationships between quantitative traits and GH-TaqI RFLPs in double-muscled Belgian White Blue bulls, the AC genotypic class was not used because of its low distribution. The AA class showed greater records of weight at 7 (P < 0.07) and 13 (P < 0.06) months of age than the AB class. In conclusion, this study has shown a correlation between the GH-TaqI RFLPs and weight at 7 and 13 months of age in Belgian White Blue bulls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1999

Analysis of MHC class II and class IV restriction fragment length polymorphism in chicken lines divergently selected for multitrait immune response.

In the present study, chickens of four lines divergently selected for high (H) and low (L) immunocompetence in replicate were analyzed to investigate polymorphisms of MHC class II and MHC class IV on the molecular level associated with selection. The long-term selection experiment for multitrait immunocompetence was carried out in replicates and allows, therefore, the opportunity to distinguish effects of selection from other genetic factors. The SacI-digested DNA was hybridized individually with MHC class II and MHC class IV gene probes. The MHC class II RFLP analysis revealed four polymorphic bands and only one of them showed a significant difference between the selection directions H and L pooled between replicates. The small frequency differences of this band relative to the long-term selection suggest that this MHC class II fragment may contain genetic elements that are only slightly associated with the immune response traits used for selection. The hybridization with the MHC class IV probe displayed 26 scorable bands, of which 18 were polymorphic. In most instances, the differences between the lines were likely caused by the influence of genetic factors other than selection for multitrait immunocompetence. Only one band displayed a consistency in difference between selection directions in both replicates and no frequency difference between replicates. This band was almost completely absent in both H sublines, but at a frequency of about 50% in both L sublines. The general results of this study did not reveal major differences in band frequencies that indicate a close association of MHC class II and MHC class IV polymorphic markers to the divergent selection for multitrait immune response. Although the MHC makes a crucial contribution in immune response, it may have been difficult to detect single-gene associations with the selection criteria of this study, because of the myriad of components contributing to general immune responses measured in vivo.

Animals↗

PubMed2004

[Molecular identification methods of yeasts of biotechnological interest].

Yeasts have numerous applications in modern and traditional biotechnology. They take place in production of food, unicellular protein and products with added value, and in the last decades they have been incorporated to the biotechnology industry as host in the production of eukaryotes proteins. Apart from their advantages, some genera are the causes of mycosis on man and in some cases, are opportunistic pathogens associated to diseases such as HIV. They are also agents responsible for the damaging of fresh and elaborated food for human consumption. For these reasons, the quick and accurate identification of industrially, environmentally and clinically significant yeasts is important. Yeast taxonomy has been supported by conventional techniques, based on morphological and physiological descriptions of species and genera, but depend on strain culture conditions, therefore they have introduced errors in yeast taxonomy and originated the duality of their nomenclature. These difficulties have been solved with the application of molecular techniques, based on the sequence analysis of nucleic acid, specially karyotiping electrophoresis, microsatellite analysis, mitochondrial DNA length polymorphism, restriction fragment length polymorphism of ribosomal RNA, ramdom amplified polymorphic DNA and low molecular weight RNA. In this review all those methods are described, which have allowed the development of identification kits for clinical and industrial application for the clearance of phylogenetic relationships among species and genera of yeasts of biotechnological interest.

Biotechnology↗

PubMed1991

Schistosoma mansoni: use of a cloned ribosomal RNA gene probe to detect restriction fragment length polymorphisms in the intermediate host Biomphalaria glabrata.

Adult susceptibility of Biomphalaria glabrata to Schistosoma mansoni infection is controlled by simple Mendelian genetics. In this study a molecular approach was used to determine the degree of genetic variation between well-defined lines of B. glabrata which are either resistant (10-R2) or susceptible (M-line) to S. mansoni infection. A cloned probe pSM389, which contains part of the S. mansoni small ribosomal RNA gene and a portion of the nontranscribed spacer was found to cross-hybridize with B. glabrata DNA and was used in Southern hybridizations to detect restriction fragment length polymorphisms (RFLPs) between the above snail stocks. Polymorphisms were noted with a variety of restriction enzymes, namely Bg/II, BamHI, AccI, AvaII, ClaI, EcoRI, EcoRV, KpnI, PvuII, and NcoI. Although most RFLPs were relatively minor, a significant difference was observed with EcoRV. Further analysis of the EcoRV RFLPs among other isolates of the resistant stock demonstrated that a high frequency of genetic variation exists even among isolates of the same origin, but maintained in separate laboratories. Interestingly, RFLPs in the EcoRV site were detected in DNA isolated from a single generation of selfed progeny of a single 10-R2 parent. RFLPs associated with this site were found to occur between B. glabrata and B. tenagophila, B. straminea, and B. schrammi, indicating that Southern blot analysis using ribosomal gene probes may be useful for the molecular differentiation of B. glabrata from other intermediate hosts and from morphologically similar species that are refractory to infection.

Animals↗

PubMed1996

Allelic variants of human TCR BV17S1 defined by restriction fragment length polymorphism, single strand conformation polymorphism, and amplification refractory mutation system analyses.

Several human TCR BV gene subfamilies, including BV3, BV14, and BV17S1, are single member genes but are overutilized among activated CD4+ synovial T cells in the rheumatoid arthritis (RA). To define the role of these TCR BV genes in the pathogenesis of disease, it is critical to characterize the genomic organization and the allelic variations of these genes. In this study we describe allelic variations of BV17S1 defined by restriction fragment length polymorphism (RFLP), single strand conformation polymorphism (SSCP), and amplification refractory mutation system (ARMS) analyses. A single nucleotide replacement (C/T) results in an amino acid substitution (F/L) in the leader and distinguishes BV17S1*1 from BV17S1*2. This nucleotide substitution was found to create a BsmAI restriction enzyme recognition site in BV17S1*2. Therefore genotypic analyses can be performed either by the SSCP or RFLP method. The analyses of 75 unrelated individuals show that the frequency for allele BV17S1*1 is 52.7% and for allele BV17S1*2 is 47.3%. Both alleles are functionally expressed and are distributed within CD4+/CD8+ T cell subsets. Another point mutation in the CDR2 region of BV17S1, which results in the amino acid replacement of Gln by His, originally identified form a cDNA clone, has now been confirmed as an allele by ARMS analysis using genomic DNA preparations and designated to as BV17S1*3. Screening of this CDR2 related variant among normal populations indicates that this is a rare allele (1 of 75). Although this variant may be of functional significance, the genotypic analysis and functional studies are difficult due to the low frequency of BV17S1*3. In an attempt to define a correlation between BV17S1 allelic usage and susceptibility to RA, the germline distribution of BV17S1 alleles *1 and *2 has been examined in a small number of RA patients and no skewed usage has been identified.

Alleles↗

PubMed1991

Detection of frequent BglII polymorphism by polymerase chain reaction and TaqI restriction fragment length polymorphism for 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase at the human HSD beta 3 locus (1p11-p13).

Analysis of amplified polymerase chain reaction products of 575 bp from the fourth exon of the human type I 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase gene at locus HSD beta 3 1p11-p13, reveals a frequent two-allele polymorphism at codon Leu338 due to a silent substitution of T by C, thus creating a BglII site leading to 371- and 204-bp fragments. Southern blot analysis of BglII-digested DNA from 57 individuals using a genomic probe detects two allelic fragments of 5.3 kb and 0.77 kb, respectively, while two allelic fragments of 3.7 kb and 3.4 kb are obtained in TaqI digests with multiple constant bands, as also observed with BglII digests.

Bacterial Proteins↗

PubMed2002

Close correlation between restriction fragment length polymorphism of L-myc gene and susceptibility to gastric cancer.

AIM: A common inherited RFLP of the L-myc proto-oncogene has been reported to correlate with cancer susceptibility. Our aim was to test the hypothesis that there was association between L-myc S allele in gastric cancer and predisposition to the disease. METHODS: The distribution of L-myc polymorphism in 25 patients with gastric cancer was determined by polymerase chain reaction-based restriction fragment length polymorphism and compared with that of 83 healthy control subjects. RESULTS: We found a significant difference, both in the distribution of the LL, LS and SS genotypes and in the allelic frequencies, between the control group and the patient group; that is, the frequencies of L-myc alleles were, L and S, 0.52 and 0.48, 0.64 and 0.36, respectively. This difference was primarily the result of a high frequency of the S allele among gastric cancer patients compared to controls. There was a significant difference in the distribution of both genotypes (P = 0.004) and allele frequencies (P = 0.005) between patients with gastric cancer and control groups. CONCLUSIONS: Our results suggested that L-myc polymorphism may be significant in an individual's susceptibility to gastric cancer in Turkey and may be useful for identifying patients at high risk of developing gastric cancer.

Alleles↗