EcoRI Restriction Fragment Length Research Articles

Molecular Characterization of Fusarium oxysporum Causing Chickpea Wilt by Internal Transcribed Spacer (ITS) Marker

Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris is one of the serious disease causes tremendous loss to crop throughout the world and has assumed serious proportions in the recent years. Wilt affected chickpea plant roots samples were collected from forty eight different regions of Maharashtra. The collected samples were characterized by designed ITS primers. The Fusarium oxysporum f. sp. ciceris (Foc) showed about 302 bp amplicon when subjected to PCR with these primers. Further the amplified product was digested with five restriction enzymes viz. AluI, EcoRI, HaeIII, MboI and MspI and restriction fragment length polymorphism (RFLP) pattern were analysed. A dendrogram derived from ITS-RFLP analysis of the rDNA region divided the Foc isolates into four clusters. The maximum genetic distance 0.75 exhibited by five Foc isolates viz. Foc-30, Foc-36, Foc-24, Foc-25 and Foc-48 belonging to Shahartakli, Shelur, Nashik, Satara, Kolhapur regions respectively and found to be more diverse among the other Foc isolates. Whereas isolate no. Foc-20, Foc-21 and Foc-8 from Ambajogai, Karjat and Rahata shown minimum genetic distance (0.13). This showed the genetic variability among the Foc isolates collected from different regions of Maharashtra.

Comparative Study between Greeks and Albanians with the Use of Restriction Fragment Length Polymorphisms of Apolipoprotein B Gene

Aim: The aim of this study was to compare the genetic polymorphisms of apolipoprotein B gene between two different populations, Greeks and Albanians living in Greece and to investigate the possibility of discriminating the two populations by using these polymorphisms. Methodology: Restriction fragment length polymorphisms at codons 2488 (XbaI) and 4154 (EcoRI) of the apolipoprotein B gene were investigated in the above populations, in order to determine if there are differences between them. Two specific DNA regions, each containing the polymorphic site, were amplified by polymerase chain reaction. The products were digested and electrophoresis on 2% agarose gel was followed. A total number of 160 unrelated individuals from each population were randomly collected. Results: The allelic frequencies of the samples from Greeks and Albanians showed variability patterns for the XbaI and EcoRI Restriction Fragment Length Polymorphisms. For Greeks and Original Research Article Ampati et al.; ARRB, 7(2): 75-83, 2015; Article no.ARRB.2015.108 76 Albanians the presence of E+/+ genotype was almost the same (67.5% and 70.6% respectively), without statistical significant differences and the E-/genotype showed low common presence (6.3% and 2.5% respectively). The presence of X-/genotype had almost the same ratio for the two populations (48.1% for Greeks and 39.4% for Albanians) and the presence of X+/+ genotype was low enough for both of them. Conclusion: The study of the two populations (Greeks and Albanians) did not show any statistically significant differences concerning the frequency of the genotypes of XbaI and EcoRI polymorphisms of the APOB gene.

Genetic Diversity of Trichomonas vaginalis Clinical Isolates Determined by EcoRI Restriction Fragment Length Polymorphism of Heat-Shock Protein 70 Genes

Restriction fragment length polymorphism (RFLP) analysis using a multilocus heat-inducible cytoplasmic heat-shock protein 70 (Hsp70) hybridization probe with EcoRI-digested genomic DNA was used in molecular typing of 129 Trichomonas vaginalis isolates. Results indicate that Trichomonas organisms exhibit considerable polymorphism in their Hsp70 RFLP patterns. Analysis of seven American Type Culture Collection reference strains and 122 clinical isolates, including 84 isolates from Jackson, Mississippi, 18 isolates from Atlanta, Georgia, and 20 isolates from throughout the United States, showed 105 distinct Hsp70 RFLP pattern subtypes for Trichomonas. Phylogenetic analysis of the Hsp70 RFLP data showed that the T. vaginalis isolates were organized into two clonal lineages. These results illustrate the substantial genomic diversity present in T. vaginalis and indicate that a large number of genetically distinct Trichomonas isolates may be responsible for human trichomoniasis in the United States.

Identification of Subtypes of CYP2D Gene Rearrangements among Carriers of CYP2D6 Gene Deletion and Duplication

Cytochrome P450 2D6 (CYP2D6) is one of the best-known polymorphic drug-metabolizing enzymes. Rapidly evolving genotyping techniques permit the identification of single-nucleotide polymorphisms (SNPs) and thereby a prediction of individual metabolic capacities for CYP2D6 substrates. A considerable part of interindividual variability in CYP2D6 enzyme activity, however, is not related to SNPs but to gene deletions and duplications. Currently used genotyping methods assume that these gene rearrangements are homogeneous. We analyzed the interindividual variability in CYP2D6 gene arrangements in genomic DNA from 740 Caucasian individuals by allele-specific PCR to identify common SNPs of the CYP2D6 gene that correspond to the variant alleles CYP2D6*3, *4, and *9. We investigated the presence and variability of CYP2D6*5 (gene deletion), CYP2D6x2 (gene duplication), and CYP2D6xn (gene amplification) by EcoRI and XbaI restriction fragment length polymorphism analyses and by long PCR plus KpnI and BamHI digestion. The presence of new mutations at the CYP2D locus was analyzed by sequencing. CYP2D6 gene rearrangements were present in >12% of individuals. Variability in the rearrangements regarding both gene deletion and gene duplication existed, and one of the unusual arrangements led to incorrect phenotype prediction. The frequency for carriers of unusual gene rearrangements was <0.3% (95% confidence interval, 0%-0.6%) in the population studied. Heterogeneity in CYP2D6 gene rearrangement exists, but the allele frequency indicates that the risk for an erroneous phenotype prediction related to such variability is extremely low and that this risk can be neglected in routine analyses.

COL1A2 (type I collagen) polymorphisms in the Colorado Indians of Ecuador

EcoRI, MspI and RsaI restriction fragment length polymorphisms (RFLPs) of the COL1A2 (type I collagen) gene are proving to be extremely informative markers for describing human populations; therefore they hold considerable potential for anthropogenetic research. The objective of this study was to characterize at the DNA level the Colorado Indians from Ecuador, for whom only blood group frequency information is available, and to investigate their relationships with the Cayapa-another Ecuadoran Native American group belonging to the same linguistic affiliation-and other world populations. Colorado Indians (n = 80) were analysed for the three anthropologically informative RFLPs of the COL1A2 gene. To better define the genetic relationship between this group and other populations, principal component analysis (PCA) was performed and genetic distances were estimated. Population genetic structure was tested through analysis of molecular variance (AMOVA) by comparing haplotype frequencies. COL1A2 allele and haplotype frequencies showed a certain degree of heterogeneity between the two Chibchan populations of Ecuador. The AMOVA test detected a significant level of differentiation (Fst = 0.034, p = 0.0049) between Colorado and Cayapa Indians. PC and genetic distance analyses showed a clear-cut separation between African and non-African populations; within the latter, the two Native American groups were differentiated from each other. The present findings suggest the presence of a low level of genetic relatedness between the Colorado and the Cayapa, despite their supposed common ethnogenesis. This confirms what has been inferred from other genetic data about the high degree of heterogeneity among Native Americans, even within the same linguistic branch, thus supporting the existence of genetic sub-structure within the central and southern American populations.

Multifocal detection of multidrug-resistant Pseudomonas aeruginosa producing the PER-1 extended-spectrum beta-lactamase in Northern Italy.

Forty-four nonreplicate clinical isolates of Pseudomonas aeruginosa that were resistant to extended-spectrum cephalosporins (ceftazidime and cefepime) and aztreonam, that putatively produced an acquired extended- spectrum beta-lactamase (ESBL), according to the results of a double-disk synergy test, and that had been involved in nosocomial outbreaks were obtained from six different hospitals in northern Italy and screened for the presence of bla(PER) ESBL determinants. Twenty isolates, associated with nine independent outbreaks that occurred in five hospitals in the Milan area and its surroundings during 1995-2000, were found to carry an acquired bla(PER-1) gene. PER-1 producers representative of the nine outbreaks exhibited a multidrug resistance (MDR) phenotype, including resistance to extended-spectrum cephalosporins, aztreonam, meropenem, aminoglycosides, and in most cases, imipenem and ciprofloxacin. An analysis of macrorestriction profiles of their genomic DNAs by pulsed-field gel electrophoresis revealed an overall clonal diversity of the PER-1 producers, although interhospital clonal spread was also observed. The bla(PER-1) gene was not transferable and appeared to be chromosomally located. An analysis of the EcoRI and EcoRV restriction fragment length polymorphisms of the bla(PER-1) locus revealed identical patterns for all isolates, and the characterization of a 1.9-kb region containing bla(PER-1) revealed a conserved structure in representatives of the various clonal lineages. The present findings indicate that MDR P. aeruginosa clones producing the PER-1 ESBL are endemic to this area of northern Italy, where they have been circulating since the mid-1990s and have been associated with several nosocomial outbreaks.

Analysis of the insulin-sensitive phosphodiesterase 3B gene in type 2 diabetes

We screened for mutations in the gene of insulin–sensitive phosphodiesterase 3B (PDE3B), which regulates antilipolytic actions of insulin via reduction of intracellular cyclic AMP levels, in Japanese patients with type 2 diabetes mellitus and lipoatrophic diabetes mellitus using single-stranded conformation polymorphism analysis and Southern analysis and investigated frequencies of variable number of tandem repeats. A silent polymorphism at the Arg 463 codon (AGG→AGA) in exon 4 was identified after examining all 16 exons and exon–intron splicing junctions of the gene. This polymorphism was found in 53 of 100 subjects with type 2 diabetes mellitus, 2 of 5 lipoatrophic diabetic patients and 24 of 50 control subjects, without any significant difference in allele frequency between groups. An EcoRI restriction fragment length polymorphism was identified in patients with type 2 diabetes mellitus and control subjects, again with no differences in occurrence. The allelic distribution of two polymorphic tandem repeats sequences in introns 5 and 12 of the gene did not differ significantly between patients with type 2 diabetes mellitus and control subjects. In conclusion, alterations in the PDE3B gene are unlikely to contribute importantly to the pathogenesis of type 2 diabetes mellitus or lipoatrophic diabetes mellitus in Japan.

Genetic diversity of Bacillus thuringiensis serovars revealed by RFLP using random DNA probes.

EcoRI and HindIII restriction fragment length polymorphism (RFLP) profiles using 2 random DNA probes, named 104 and 106, were generated for 85 B. thuringiensis strains. These include 80 serovars, 4 intra-serovar strains: kurstaki HD-1, dendrolimus, tenebrionis and sandiego, and a non-serotypeable strain B. thuringiensis var. wuhanensis. A total of 47 EcoRI and 65 HindIII restriction patterns were generated when hybridization results from both probes were combined. Seventy-seven B. thuringiensis strains showed distinctive hybridization profiles. The dendrogram resulting from the numerical analysis of the distance matrix revealed fourteen distinct phylogenetic groups at the 96% banding patterns similarity. The intra-serovar strains showed higher similarity with their respective type serovars. However, different serovars from a common H-serotype did not always cluster in the same phylogenetic group. Alternatively, several mosquitocidal serovars clustered in a single phylogenetic group. The correlation between serotyping and banding pattern similarity is discussed.

Biochemical and molecular characterization of erthromycin-resistant avian Staphylococcus spp. isolated from chickens

The epidemiology of the two common erythromycin-resistant methylase (erm) genes ermC and ermA was analyzed in 12 coagulase-negative Staphylococcus spp. and 34 coagulase-positive Staphylococcus spp. isolated from chicken. Southern hybridization indicated that only 2 of the 12 coagulase-negative Staphylococcus spp. strains contained the ermC gene on the plasmid; 1 strain of Staphylococcus xylosus harbored the ermC gene on a 2.5-kb plasmid, and 1 strain of Staphylococcus cohnii harbored the gene on a 4.0-kb plasmid. Twelve of the 34 strains of Staphylococcus aureus contained the ermC gene. Eleven of these strains had the ermC gene on a 2.5-kb plasmid, and 1 strain had the gene on a 4.0-kb plasmid. Ten of the 12 coagulase-negative Staphylococcus spp. and 22 of the 34 coagulase-positive Staphylococcus spp. harbored the ermA gene exclusively on the chromosome. Two different ermA EcoRI restriction fragment length polymorphisms (RFLP) were identified. A majority of the isolates was found to have two chromosomal inserts (8.0- and 6.2-kb EcoRI fragments) of ermA. One strain of S. aureus had different chromosomal inserts (6.4- and 5.8-kb EcoRI fragments) of ermA. Our results indicate that either the ermC or ermA gene, homologous to those described in human isolates, was present in all avian Staphylococcus spp. and that ermA was the predominant gene in coagulase-negative and coagulase-positive avian Staphylococcus spp. The size and copy numbers of the ermA gene were different from its human counterpart.

Gene Polymorphisms for Plasminogen Activator Inhibitor-1/Tissue Plasminogen Activator and Development of Allograft Coronary Artery Disease

Impaired fibrinolytic activity has been linked to the presence and severity of allograft vasculopathy (Tx CAD). This impairment may be associated with the presence of certain fibrinolytic protein gene polymorphisms. To investigate the relation between donor-specific fibrinolytic protein genotypes and Tx CAD, we identified donor plasminogen activator inhibitor-1 (PAI-1) HindIII and tissue plasminogen activator (TPA) EcoRI restriction fragment length polymorphisms-based genotypes by Southern blot analysis in 48 recipients of cardiac allografts and correlated these genotypes with the development of CAD. No association was found between donor TPA genotypes and the presence of Tx CAD. Among the 48 patients, 17% were homozygous for the 1/1 PAI-1 genotype, 51% for the 2/2 PAI-1 genotype, and 32% for the 1/2 PAI-1 genotype. The actuarial freedom from any CAD for the recipients with each respective donor PAI-1 genotype at 12 and 24 months was 100% and 100% for the 1/1 PAI-1 genotype, 92% and 92% for the 1/2 PAI-1 genotype, and 75% and 45% for the 2/2 PAI-1 genotype (P=0.03). Recipients with a diseased 2/2 PAI-1 genotyped allograft had longer ischemic times (P=0.02) than those recipients with a Tx CAD-free allograft. These data suggest that recipients with a 2/2 PAI-1 genotype are at a significant risk of developing Tx CAD. This genotype may serve as a useful screening tool for predicting the future development of Tx CAD.

A test of EcoRI and HindIII restriction fragment length polymorphisms in assessing susceptibility for scrapie in US Suffolk sheep

We investigated the distribution of EcoRI restriction fragment length polymorphism (RFLP) and tested EcoRI and HindIII RFLPs to ascertain the occurrence of scrapie in Suffolk sheep. Genomic DNA samples were collected from 527 animals and typed for EcoRI RFLP by Southern blot analysis using the PrP gene clone probe (pNPU42). The average e1 frequency in Suffolk sheep was 64.4% and ranged from 51.5 to 82.2%, which was significantly higher than the average in Cheviot (32.3%) and Rambouillet sheep (17.7%). The association of histopathologic diagnosis with RFLPs was investigated using 82 animals exposed orally with scrapie inoculum in a double-blind, retrospective experimental design. There was a significant ( P<0.01) association between EcoRI RFLP and scrapie histopathologic diagnosis in Suffolk sheep with the e1e1 genotype. The use of the EcoRI RFLP phenotype for scrapie-diagnosis, however, was inconsistent for some individual cases. HindIII-produced RFLPs was not significantly related to scrapie diagnosis.

Ultrarapid metabolism of sparteine

CYP2D6 is a polymorphically expressed enzyme with two phenotypes. Poor metabolizers lack the enzyme caused by inactivating mutations in the CYP2D6 gene and extensive metabolizers have at least one active CYP2D6 gene. Extensive metabolizers with very high capacity for CYP2D6 dependent drug metabolisms are termed ultrarapid metabolizers and carry alleles with duplicated, multi duplicated or amplified CYP2D6 genes. In the present study, we examined the frequency of CYP2D6 gene duplications in a Danish population and validated a long polymerase chain reaction method for identification of ultrarapid metabolizers. Sixty individuals having a metabolic ratio for sparteine at or below 0.15 were selected and a control group of 53 individuals with a metabolic ratio between 0.16 and 12.4 was used. Based on EcoRI restriction fragment length polymorphism analysis, eight individuals were found with a duplicated CYP2D6 gene, whereas using a long polymerase chain reaction method, nine individuals with a 3.6 kb fragment indicative of two CYP2D6 genes in tandem were found among the 60 individuals with a low metabolic ratio. No gene duplication was found in the control group or in any individuals with a metabolic ratio > 0.14. Based on these results, we estimate the frequency of individuals with CYP2D6 duplication in the Danish population to be 0.8%, which is comparable to the frequency in the Swedish and the German populations, but considerably lower than in Spanish or African populations. We conclude that the long polymerase chain reaction assay is simple and reliable for detection of duplications of the CYP2D6 gene.

Restriction fragment length polymorphism of the L-myc oncogene in non-Hodgkin's lymphoma patients from India

We examined 89 non-Hodgkin's lymphoma (NHL) patients of Indian origin for EcoRI restriction fragment length polymorphism (RFLP) of the L-myc gene with a view to testing the hypothesis that the presence of the L-myc S-allele predisposes towards NHL. We found no significant difference either in the distribution of the LL, LS and SS genotypes or in the allelic frequencies between the patient group and the control group with the frequencies of L-myc alleles, L (10.0 kb) and S (6.6 kb), being 0.56 and 0.44, respectively, in the patient group and 0.54 and 0.46, respectively, in the control group. However, a higher proportion (70%) of the S-allele was observed in our control group of normal healthy volunteers. Thus, the presence of L-myc S-allele did not indicate increased susceptibility or predisposition to the malignancy.

Chromosomal location of the human immunoglobulin lambda variable 8 (IGLV8) gene family outside the major λ locus on chromosome 22q11.2

Physical mapping of the human immunoglobulin λ locus (IGL) on chromosome 22q11 has shown the existence of at least 52 variable region gene segments. These Vλ genes are associated with EcoRI fragments detectable in Southern blots of genomic DNA samples. The current physical map of the IGL locus includes a unique Vλ8 gene (IGL8a, accession no. Z73650) in a 3.7 kb EcoRI fragment. However, our Southern blot- EcoRI-restriction fragment length polymorphism studies on the Brazilian population using a specific probe for the Vλ8 gene (pVL8 probe) have revealed the presence of two additional fragments bearing Vλ8 sequences (8.0 kilobase (kb) at 100% frequency and 6.0 kb at 10% frequency). We have used human/rodent somatic cell hybrid DNAs to locate these new Vλ8 genes outside the major locus on chromosome 22q11.2. Polymerase chain reactions using specific primers for the IGLV8a gene on the somatic hybrid panel showed that chromosome 8 (besides 22q11) also comprises Vλ8 sequences. This finding represents evidence for the dispersion of the human IGLV8 gene family outside the major locus (orphan genes).

DNA polymorphisms of apolipoprotein B in the population of Senegal.

Three apolipoprotein B (apoB) genetic polymorphisms, the XbaI, MspI and EcoRI restriction fragment length polymorphisms (RFLPs), were analysed for 221 individuals in Senegal by polymerase chain reaction. Allelic frequency determination revealed that this population has 0.79 XbaI- (X-), 0.96 MspI+ (M+), and 0.89 EcoRI+ (E+). Major genotypes were X-/X- (0.62), M+/M+ (0.92) and E+/E+ (0.80). The XbaI allele frequency is different (p < 10(-9)) from that in Caucasians (0.47) and from that in Mongoloids (0.98). Significant differences between Senegalese and Caucasians, and between Senegalese and Mongoloids were also observed for the EcoRI and MspI alleles of the apoB genes.

A Study of Phage- and Ribotype Patterns of Staphylococcus aureus Isolated from Bovine Mastitis in the Nordic Countries

This study was conducted to investigate the geographical distribution of phage and ribotypes of Staphylococcus aureus causing bovine mastitis in the 5 Nordic countries. A total of 403 isolates of S. aureus was isolated from 403 different dairy herds. One hundred five strains were isolated in Denmark, 81 in Finland, 17 in Iceland, 96 in Norway and 104 in Sweden. The isolates were phage typed and characterized for their EcoRI restriction fragment length polymorphisms of the genes encoding ribosomal RNA (ribotyping). A total of 351 (87%) of the 403 isolates could be typed by phages assigning them to 25 different phage types. Two to 3 different phage types predominated within each country. One type (29/52) accounted for 36% of all the isolates and was found in 4 of the countries. A total of 87 different ribotypes was found among the isolates investigated. As for phage typing 2 to 3 different types predominated within countries. However, except for one type (ribotype 1), which was commonly found in Denmark, Sweden and Finland, different ribotypes predominated within each country. The combination of phage and ribotyping assigned the isolates to 178 different types. Ninety-six percent of the isolates of ribotype 1 belonged to phage type 29/52. This combined type accounted for 17% of all the 403 isolates. These findings show that a large number of different types of S. aureus can be isolated from cases of bovine mastitis. However, few types predominate within different countries. These predominating types seem to be specific in each country, however, a single type was common for both Denmark, Sweden and Finland. This could suggest differences in the virulence or in modes of transmission of predominating and rare types of S. aureus associated with bovine mastitis.

Application of chromosome 4q35-qter marker (pFR-1) for DNA rearrangement of facioscapulohumeral muscular dystrophy patients in Taiwan

Facioscapulohumeral muscular dystrophy (FSHD) has been found to be linked to chromosome 4qter. A chromosome 4q35-ter marker, pFR-1 (subclone of the cosmid c51), has been recently isolated and used as a probe for mapping near, or within, the FSHD gene. To examine FSHD-associated DNA rearrangements in the Taiwan population, we used the pFR-1 probe to perform Southern blot analysis on 142 individuals, including 32 FSHD patients within 9 autosomal dominant families, five sporadic FSHD patients from 4 families (include one pair of twins), three sporadic scapuloperoneal syndrome (SPS) patients and two sporadic polymyositis patients with their unaffected parents, and 29 healthy controls. In 29 healthy individuals, 3 SPS and 2 polymyositis patients with their families, probe pFR-1 analysis revealed that all had polymorphic restriction fragments that were larger than 28 kb in length. All but 1 FSHD-affected individual had specific smaller EcoRI fragments (ranging in size from 10.5 to 27 kb). Two point linkage analysis between pFR-1 and the FSHD locus provided significant evidence for FSHD linkage (Z max=6.84). A similar smaller fragment was also present in 5 sporadic patients, while this smaller fragment could not be found in one of their parents. Identical EcoRI restriction fragment length polymorphism (RFLP) patterns linked to FSHD were shown in the monozygotic twins, even though they showed extreme variability in the expression of FSHD. We conclude that the pFR-1 probe is a tightly linked marker of FSHD and can be used to detect most DNA rearrangements associated with this disease in the Taiwan population. However, the same RFLP patterns may represent extreme variability in the expression of the FSHD gene.

Detection of an EcoRI restriction fragment length polymorphism in the gene encoding the human TBP associated factor II 30 (TAFII30)

Detection of an EcoRI restriction fragment length polymorphism in the gene encoding the human TBP associated factor II 30 (TAF_II30)

Allelic association between D2 but not D1 dopamine receptor gene and alcoholism in Finland.

We studied the relationship of D2 and D1 receptor gene polymorphisms and alcoholism in male Finnish alcoholics and assessed male controls. Seventy alcoholics entering a detoxification programme and 50 control individuals were recruited. Forty-three per cent of the alcoholic patients, but only 22% of controls, had the D2 receptor gene TaqI A restriction fragment length polymorphism A1 allele. The frequency of the A1 allele was significantly higher in alcoholics (p = 0.039). In comparison, no association between alcoholism and the D1 receptor gene EcoRI restriction fragment length polymorphism alleles was found. A logistic regression analysis of the alcoholic population failed to support the idea that the presence of the A1 allele would be linked to estimates of alcohol dependence severity rated with the Severity of Alcohol Dependence Questionnaire or the Michigan Alcoholism Screening Test. In conclusion, allelic association between the D2 but not D1 receptor gene and alcoholism in a genetically relatively homogenous population of male Finns was found. The results are in agreement with the view that the D2 receptor locus is involved in genetic susceptibility to alcoholism but does not give support to a special association of severe alcohol dependence and the A1 allele of the D2 receptor gene.

MYCL genotypes and loss of heterozygosity in non-small-cell lung cancer.

Some studies have suggested that the S allele of the MYCL oncogene, which results from an intragenic EcoRI restriction fragment length polymorphism (RFLP), may be associated with cancer susceptibility. In addition, this allele has also been linked to metastases and adverse survival in certain cancers, although studies of lung cancer patients from different populations have yielded controversial results. We studied 108 cases of surgical resected non-small-cell lung cancer (NSCLC) and found no evidence that MYCL genotypes were associated with tumour progression or a worse prognosis. However, the presence of loss of heterozygosity (LOH) at this chromosome 1p32 locus correlated significantly with regional lymph node involvement, as well as advanced TNM stage. These data indicate the existence of a chromosome 1p candidate tumour-suppressor gene(s), possibly in linkage disequilibrium with the EcoRI RFLP in specific populations, which appears to play a role in determining tumour progression in NSCLC. Refined mapping of the critical region of loss should help attempts to identify and clone the candidate gene.