Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Genetic polymorphisms”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,693 records · Page 94Linked to original sources
PubMed2005

Genetic polymorphisms of FAS and FASL (CD95/CD95L) genes in cervical carcinogenesis: An analysis of haplotype and gene-gene interaction.

OBJECTIVE: Whereas human papillomavirus (HPV) infection is necessary but not sufficient for cervical carcinogenesis, host genetic variations may confer individual susceptibility. Resistance to apoptosis is a hallmark of cancer in which FAS/FAS ligand signaling plays an important role. The present study examines the hypothesis that genetic polymorphisms in FAS and FAS ligand genes, alone or in combination, are associated with cervical carcinogenesis. METHODS: The genotypes of FAS -670A/G, FAS -1377G/A, and FASL -844C/T were assessed in 143 patients with high-grade squamous intraepithelial lesions (HSIL), 175 patients with invasive squamous cell carcinomas (SCC), and in age-matched controls by real-time PCR with allele-specific TaqMan probes. The status of cervical high-risk HPV infection was determined and adjusted to test the independence of genotype in the risk assessment. RESULTS: The A-allele and AA-genotype frequencies of FASA -670G were significantly higher in HSIL/SCC than in controls (60% vs. 54%, P = 0.04, OR 1.26 [95% CI 1.01-1.57]; 38.0% vs. 28.6%, P = 0.02, OR 1.70 [95% CI 1.07-2.70]). No association between FAS -1377 or FASL -844 polymorphisms and HSIL/SCC could be identified. The FAS -1377A/-670A haplotype conferred a higher risk for HSIL/SCC (OR 3.05, 95% CI 1.28-7.30) than FAS -670A alone (OR 1.26, 95% CI 1.28-7.30). The interaction between FAS -670AA and FASL -844CC genotypes was associated with a risk of HSIL/SCC (OR 2.13, 95% CI 1.06-4.29) higher than that of the FAS -670AA genotype alone (OR 1.70, 95% CI 1.07-2.70). CONCLUSIONS: The FAS -1377A/-670A haplotype in combination with FASL -844C is associated with cervical carcinogenesis.

Alleles↗
PubMed2003

[Genetic polymorphism and the population difference of 7 Y-STR loci and haplotypes in Chinese Han and Japanese populations].

OBJECTIVE: To investigate the genetic polymorphism of 7 Y-STR loci and haplotypes and analyze their population difference. METHODS: The DNA samples from 45 Chinese Han and 59 Japanese men were analyzed by PCR and the denatured PAGE followed by silver staining. RESULTS: 33 alleles were identified for 6 loci including DYS393, DYS389 I, DYS19, DYS390, DYS389 II and DYS392, 39 alleles were identified for DYS 385, the frequency distributions were between 0.0169-0.6444, the DP value distributions of them were between 0.5406-0.9579, the DP value of DYS 385 was the highest. With the comparison of data of the 7 loci, significant difference in genetics was observed between the two populations(P < 0.05). There were 95 haplotypes that consisted of the 7 loci, Chinese Han had 41 haplotypes, DP value 0.9960, Japanese population had 54 haplotypes, DP value 0.9965, no common haplotypes were found between them. CONCLUSION: The 7 STR loci above belong to loci of high discriminating ability, the haplotypes are highly polymorphic and their ethical character is apparent.

Asian People↗
PubMed2002

Genetic polymorphisms in the cytochrome P450 1A1, glutathione S-transferase M1 and T1, and susceptibility to colon cancer.

Several polymorphic cytochrome P-450 and glutathione S-transferase (GST) enzymes are involved in the activation and detoxification of many potential carcinogens and may therefore be important in susceptibility to cancer induction. CYP1A1 MspI, GSTM1, and GSTT1 are polymorphic enzymes and some alleles have been correlated with an increased risk of developing some cancers. In the present study, we examined possible associations between genetic polymorphisms of CYP1A1 MspI, GSTM1, and GSTT1 and colon cancer in a United Kingdom population. An excess of CYP1A1 MspI, and GSTM1 null genotypes was observed amongst colon cancer patients, although this did not reach the level of statistical significance. We found no significant increase in the risk of colon cancer for either CYP1A1 MspI (OR = 1.39; 95%CI: 0.46-4.21) or GSTM1 null (OR = 1.41; 95%CI: 0.76-3.01) genotypes. Individuals with GSTT1 null genotype had no association with colon cancer (OR = 0.42; 95%CI: 0.09-2.02). No significant association was observed in the site of colon cancer (proximal vs. distal). This study suggests that the polymorphisms of CYP1A1 MspI, GSTM1, and GSTT1 are not associated with a significant risk of developing colon cancer in a United Kingdom population.

Adolescent↗
PubMed2000

Genetic polymorphism and clinical outcome: identification of individuals at risk of a poor clinical outcome.

Susceptibility and outcome in complex disorders such as asthma and cancer appear to be determined, at least in part, by genetic polymorphism. However, while our ability to identify new allelic variants and study them in case and control populations has greatly improved, considerable difficulties remain in elucidating how many genes determine particular clinical phenotypes. This is because most studies have concentrated on study of single genes in relatively small study groups. The important issues of gene-gene interactions (epistasis) and high-risk subgroups have not yet been adequately addressed. We now describe a general approach, using patients with head and neck cancers as an example. Our purpose is to demonstrate candidate gene selection, statistical approaches, and identification of patient subgroups.

Genetic Predisposition to Disease↗
PubMed1983

[Genetic polymorphism of the alpha chain of spectrin].

On 80 black or white subjects, spectrin subunits were purified by SDS-polyacrylamide gel electrophoresis and subjected to limited alpha-chymotryptic digestion according to the Cleveland method. A genetic polymorphism exists in spectrin alpha chain and is not associated with a membranous disease. Up to now, this variant has only been detected in the black population.

Black People↗
PubMed1996

Examination of two genetic polymorphisms within the renin-angiotensin system: no evidence for an association with nephropathy in IDDM.

Premature cardiovascular disease is common in insulin-dependent diabetic (IDDM) patients who develop diabetic nephropathy. Genetic polymorphism within the renin-angiotensin system has been implicated in the aetiology of a number of cardiovascular disorders; these loci are therefore candidate genes for susceptibility to diabetic renal disease. We have examined the angiotensin converting enzyme insertion/deletion polymorphism and angiotensinogen methionine 235 threonine polymorphism in a large cohort of Caucasian patients with IDDM and diabetic nephropathy. Patients were classified as having nephropathy by the presence of persistent dipstick positive proteinuria (in the absence of other causes), retinopathy and hypertension (n = 242). Three groups were examined for comparison: ethnically matched non-diabetic subjects (n = 187); a geographically defined cohort of newly diagnosed diabetic patients (n = 341); and IDDM patients with long duration of disease (> 15 years) and no evidence of overt nephropathy (n = 166). No significant difference was seen in distribution of angiotensin converting enzyme or angiotensinogen genotypes between IDDM patients with nephropathy and recently diagnosed diabetic subjects (p = 0.282 and 0.584, respectively), nor the long-duration non-nephropathy diabetic subjects (p = 0.701 and 0.190, respectively). We conclude that these genetic loci are unlikely to influence susceptibility to diabetic nephropathy in IDDM in the United Kingdom.

Adult↗
PubMed2005

Innate immune receptor genetic polymorphisms in pouchitis: is CARD15 a susceptibility factor?

BACKGROUND: Pouchitis is a frequent complication after ileal pouch-anal anastamosis (IPAA) for ulcerative colitis (UC). The aim of this study was to determine whether genetic polymorphisms in the innate immune receptors toll-like receptor (TLR)4 and caspase activation and recruitment domain family member 15 (CARD15) genes are associated with pouchitis. METHODS: From a retrospectively ascertained cohort of patients with UC 5 to 12 years after IPAA (n = 101), subjects were classified into 3 groups: no pouchitis (n = 52); 1 to 2 episodes per year (n = 11), and more than 2 episodes per year (n = 38). Single nucleotide polymorphisms in the tlr4 gene (D299G, T399I) were determined by a real-time polymerase chain reaction-based fluorogenic probe technique; and card15 polymorphisms (L1007fsinsC, R702W, G908R) were determined by pyrosequencing. RESULTS: Pouchitis affected 49% (49/101) of the study population. No correlation between pouchitis and the presence of TLR4 polymorphisms was found. The percentage of patients who harbored CARD15 mutations was significantly higher in patients with pouchitis than in patients without pouchitis (18% versus 8%; P < 0.05); 24% of pouchitis patients with more than 2 episodes per year harbored CARD15 mutations (P < 0.01 compared with the no pouchitis group). The CARD15 insertion mutation L1007fsinsC was present in 14% of patients with pouchitis and in 0% without pouchitis (P < 0.05). All patients who carried L1007fsinsC developed more than 2 episodes per year. CONCLUSIONS: CARD15 polymorphisms are seen in greater frequency in patients with pouchitis after IPAA for UC. These findings, if borne out in prospective analyses, suggest that CARD15 mutations, particularly L1007fsinsC, may predispose to the development of pouchitis after IPAA for UC.

Adult↗
PubMed2002

Catechol O-methyltransferase genetic polymorphism in panic disorder.

OBJECTIVE: The authors examined the distribution of catechol O-methyltransferase (COMT) genotypes in patients with panic disorder as well as the relationship between a COMT polymorphism and the clinical characteristics of these patients. METHOD: Fifty-one patients with panic disorder and 45 healthy comparison subjects were tested for a genetic polymorphism of COMT. Clinical variables were assessed for the patients with panic disorder. RESULTS: The frequency of the L/L genotype was significantly higher in the patients with panic disorder than in the healthy subjects (19.6% versus 2.2%). Panic disorder was significantly associated with the L allele and L/L genotype. Patients with panic disorder who had the L/L genotype showed poorer treatment response than those with other genotypes. CONCLUSIONS: These results suggest that the L/L genotype of the COMT gene may be related to the development and treatment outcome of panic disorder in some patients.

Adult↗
PubMed2005

[Genetic polymorphism of bluegrass cultivars detected by RAPDs].

Kentucky bluegrass (Poa pratensis L.) is a hardy, persistent forage and turf grass adapted to a wide range of soils and climates. Its ever-increasing adoption in highly cared-for sports fields has attracted the attention of many seed companies. However in the past, the breeding of elite varieties was often hampered by the extreme complexity of the genome. The polymorphism is important for broading the genetic basis and may be exploited for application of heterosis. The genetic relationship of 16 bluegrass cultivars, including 15 accessions Kentucky bluegrass cultivars and 1 entries Canada bluegrass (Poa compressa L.) cultivar from different breeding company were analyzed using 25 RAPD markers. 25 RAPD primers generated 218 bands, of which 196 bands (89.91%) were polymorphism. It showed that the Canada Bluegrass was separated from other Kentucky Bluegrass and genetic polymorphism in the Kentucky Bluegrass cultivars was low, the genetic similarity among the cultivars fell between 66%-98%. Dendrogram obtained using these molecular markers were partly in agreement with their separated morphologic character. Cultivars from the same company were not clustered in one group.

Cluster Analysis↗
PubMed2004

Association of p53 genetic polymorphism (Arg72Pro) with estrogen receptor positive breast cancer risk in Japanese women.

Since it is well established that inactivation of p53 is involved in pathogenesis of breast cancer, it seems to be reasonable to assume that p53 genetic polymorphism at codon 72 (p53Arg72Pro) which affects the function of p53 might have an influence on breast cancer risk. Thus, in the present study, we have studied the association of p53Arg72Pro polymorphism with breast cancer risk. A case-control study was conducted with 191 breast cancer patients and 218 healthy female controls. p53Arg72Pro polymorphism was examined in their association with breast cancer risk after adjustment for the epidemiological risk factors. Relationship between p53Arg72Pro polymorphism and clinicopathological characteristics of breast cancers was also studied. In addition, frequency of somatic p53 mutation was compared according to the genotype of p53Arg72Pro polymorphism. p5372Pro/Pro homozygotes showed a significant increase in the risk of estrogen receptor (ER) positive breast cancer (adjusted odds ratio (OR) = 2.04, P = 0.04) as compared with p5372Arg/Arg homozygotes, whereas such an association was not found between p5372Pro/Pro homozygotes and ER negative breast cancer risk. Subset analysis according to menopausal status showed that p5372Pro/Pro homozygotes were significantly associated with ER positive breast cancer risk in postmenopausal women (adjusted OR = 3.42, P = 0.01) but not in premenopausal women. Frequency of ER positive tumors was significantly (p < 0.01) higher in breast cancer patients with p5372Pro/Pro genotype (82.8%) than those with p5372Arg/Arg genotype (54.5%). Mutational analysis of p53 in tumors showed that p5372Pro/Pro homozygotes had a lower frequency of p53 mutation (3.5%) than p5372Arg/Arg homozygotes (10.5%). It is suggested that p53Arg72Pro polymorphism is associated with ER positive breast cancer risk, especially, in postmenopausal women. The higher frequency of p53 somatic mutation in p5372Arg/Arg homozygotes than p5372Pro/Pro homozygotes is consistent with the thesis that the function of p5372Pro/Pro is impaired so that a further alteration of p53 gene is less required in p5372Pro/Pro homozygotes than p5372Arg/Arg homozygotes.

Adult↗
PubMed1996

Lack of relation between genetic polymorphism of cytochrome P-450IID6 and sporadic idiopathic Parkinson's disease.

We investigated genetic polymorphism of the cytochrome P-450 CYP2D6 gene from white patients with idiopathic Parkinson's disease (IPD). The mutations of the CYP2D6 gene associated with the poor metabolizer (PM) phenotype of the debrisoquine/sparteine polymorphism were analyzed in DNA of 130 IPD patients by a polymerase chain reaction (PCR)-based DNA amplification combined with Xba I restriction fragment length polymorphism (RFLP) analysis in 105 patients. Another mutation located in exon 6 was analyzed by Hha I RFLP in 94 IPD patients. The frequencies of the different CYP2D6 gene mutations were compared to the frequencies in sex- and age-matched white control population with chronic bronchitis. The rate of genotypically defined PM and the frequencies of the different mutations were not significantly different in IPD patients and controls. These results fail to confirm the previously reported results concerning CYP2D6 gene mutations in IPD. These equivocal results might be related to methodologic problems. However, other hypotheses have been suggested: impairment of neuronal CYP 2D6 expression, transient modification of CYP 2D6 phenotype, or linkage of CYP2D6 gene to the candidate gene locus directly involved in IPD.

Aged↗
PubMed2002

Genetic polymorphisms of the apolipoprotein A-IV in a Greek population and their relation to plasma lipid and lipoprotein levels.

Apolipoprotein (apo) A-IV is a protein component of triglyceride-rich lipoproteins and high-density lipoproteins (HDL). In this study, two common genetic polymorphisms of the apoA-IV gene [codons 347(allele A and T) and 360 (allele 1 and 2)] were investigated in Greek patients with hyperlipidaemia and in healthy individuals matched for age, sex and smoking habits. In both study populations we evaluated the effect of these polymorphic sites on lipid and lipoprotein plasma levels and the body mass index (BMI). The frequencies of the 1/1 and 1/2 genotypes in codon 360 were 0.94 and 0.06 in hyperlipidemic patients and 0.92 and 0.08 in the control population, respectively. The frequencies of the A/A, A/T and T/T genotypes in codon 347 were 0.62, 0.34 and 0.04 in hyperlipidemic patients and 0.59, 0.33 and 0.08 in the control population, respectively. None of the above genotype frequency differences between the study populations reached statistical significance. The control population was not affected by any polymorphism of the apo A-IV gene. Hyperlipidaemic patients, carriers of the allele 2 (1/2 genotype), had significantly lower plasma triglyceride levels than carriers of the allele 1 (p = 0.03). Genetic variation in codon 347 had no influence on lipid and lipoprotein plasma levels. None of the polymorphisms at codons 360 and 347 affected the BMI. In conclusion, this study describes for the first time the genotype frequencies for polymorphic sites in codons 360 and 347 of the apo A-IV gene in a Greek population and suggests that the presence of the allele 2 is associated with lower plasma triglyceride levels in hyperlipidaemic patients.

Apolipoproteins A↗
PubMed2006

Glutathione S-transferase M1 and GST T1 genetic polymorphisms and Raynaud's phenomenon in French vinyl chloride monomer-exposed workers.

Occupational vinyl chloride monomer (VCM) exposure can induce Raynaud's phenomenon (RP). However, not all VCM workers developed RP, which suggests an underlying genetic susceptibility. Genetic polymorphisms of glutathione S-transferases (GSTs), involved in VCM metabolism, have been shown to influence certain VCM-related health effects. We have conducted a case-control study of 58 subjects with RP along with 247 subjects without RP, from a population of 305 French workers exposed or formerly exposed to VCM, to assess any association between GST M1 and GST T1 gene polymorphisms, either separately or in combination, and the presence of RP. None of the GST M1 or GST T1 genotypes were significantly associated with the presence of RP among studied VCM workers. A combination of positive genotypes for both GST M1 and GST T1 was significantly associated with RP presence, compared to the other combinations of genotypes (OR=2.1, 95% CI=1.1-3.8). OR adjusted for age, smoking status, alcohol consumption and history of treated hypertension did not reach significance (OR=2.0, 95% CI=0.9-5.2). None of the GST M1 and GST T1 genotypes seem to contribute separately to the presence of RP, suggesting that they are not, when taken alone, a major determinant of interindividual variability for VCM-induced PR. However, the combination of both positive GST M1 and GST T1 genotypes appears to contribute slightly to susceptibility to RP in VCM-exposed subjects. Nevertheless, our study-the first to examine the role of a genetic component in the occurrence of RP secondary to occupational exposure to a chemical-corroborates the previous considerations that interaction between the genetic constitution and environmental factors is of importance in determining the health-adverse effects of VCM exposure.

Aged↗
PubMed2005

Genetic polymorphisms of alcohol and aldehyde dehydrogenase, dopamine and serotonin transporters in familial and non-familial alcoholism.

One hundred and eleven male patients with alcohol dependence and 123 nonalcoholic healthy men were tested for the genetic polymorphisms of alcohol dehydrogenase 2 (ADH2), aldehyde dehydrogenase 2 (ALDH2), serotonin transporter (5-HTT) and dopamine transporter (DAT1). There were significant differences in genotype frequencies of ADH2 C992G and A13543G SNPs between alcoholic patients with family history of alcohol dependence (familial) and alcoholic patients without family history (non-familial). Genotype and allele frequencies of ALDH2 G1951A SNP in familial or non-familial alcoholic patients differ from normal controls. Neither 5-HTTLPR L/S nor DAT1 G2319A SNP genotypes nor alleles discriminated alcoholic patients from normal controls. These findings suggest that the genetic characteristics of alcohol metabolism in non-familial alcoholics fall between non-alcoholism and familial alcoholics.

Adult↗
PubMed2005

[Association of genetic polymorphisms in plasminogen activator inhibitor-1 gene and 5,10-methylenetetrahydrofolate reductase gene with recurrent early spontaneous abortion].

OBJECTIVE: To explore the relationship of plasminogen activator inhibitor-1 (PAI-1) gene-675 4G/5G and methylenetetrahydrofolate reductase(MTHFR) gene C677T polymorphisms to recurrent early spontaneous abortion(RESA). METHODS: One hundred and twenty-seven currently non-pregnant women with at least 3 unexplained spontaneous abortions during the first trimester of pregnancy (patient group). Normal control group consisted of 117 currently non-pregnant women with at least 1 pregnancy and without a history of prematurity, miscarriage, stillbirth, eclampsia and other pregnancy complications. The genotypes of PAI-1 gene and MTHFR gene were assessed by polymerase chain reaction-restrictive fragment length polymorphism. RESULTS: The frequencies of 4G/4G genotype and 4G allele of PAI-1 were higher in patient group (45.7% and 66.1%) than in normal controls (17.1% and 46.6%) (P < 0.01). The PAI-1 4G/4G genotype was significantly associated with RESA (OR = 4.8, 95% CI: 2.23 - 10.35). Besides, MTHFR gene T/T genotype and T allele frequencies were increased in RESA patients (43.3% and 66.5%) versus normal controls (21.4% and 52.6%) (P < 0.01). The patients carrying T/T genotype had a high risk of early spontaneous abortion (OR = 3.2, 95% CI: 1.40 - 7.30). In additionìthe presence of the PAI-1 gene 4G/4G genotype together with the T/T genotype of the MTHFR gene was found to be a risk factor (OR = 6.20, 95% CI: 2.62 - 14.67) for RESA greater than the 4G/4G genotype or the T/T genotype alone. CONCLUSION: The above findings suggest that genetic polymorphisms of PAI-1 4G/5G and MTHFR C677T were associated with RESA. They may have synergetic impact and present gene dosage effect on the susceptibility to the development of early spontaneous abortion.

Abortion, Habitual↗
PubMed2003

Persistent Helicobacter pylori infection and genetic polymorphisms of the host.

Helicobacter pylori (HP) infection elevates the risk of gastric diseases including peptic ulcer and gastric cancer. The infection induces inflammatory cytokines, which could work both for and against lifetime infection in the human stomach. Genetic polymorphisms of the cytokines and other related ligands, receptors, and enzymes may influence persistent HP infection. This paper summarizes studies done on the associations between anti-HP antibody seropositivity and polymorphism genotypes. To date, the associations with the polymorphisms of fucosyl transferase 2 (FUT2 or secretor gene), FUT3 (Lewis gene), interleukin 1A (IL-1A), IL-1B, IL-1RN, IL-8, IL-10, myeloperoxidase (MPO), and tumor necrosis factor A (TNF-A) and TNF-B have been reported. Polymorphisms of other related genes, CD14, CXC chemokine receptor 2 (CXCR2), IL-1RI, nuclear factor KB2 (NF-KB2), and Toll-like receptor 4 (TLR4), have the potential to influence persistent infection. Unpublished results from our datasets are reported here for all these polymorphisms except TLR4. Gene-environment interactions between these genotypes and smoking are reviewed. An effect on OR due to the involvement of unexposed subjects is demonstrated to elucidate a disadvantage in the studies done in areas where the majority of the population is not exposed to HP.

Alleles↗
PubMed2003

CYP1A1 and GSTM1 genetic polymorphisms and lung cancer risk in Caucasian non-smokers: a pooled analysis.

Polymorphisms for genes encoding the metabolic enzymes cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) might contribute to the variability in individual susceptibility to lung cancer. The role of CYP1A1 and GSTM1 in lung carcinogenesis might be more important at low levels of exposure to carcinogens. Non-smokers represent a population at low exposure, however, they are often overlooked because of the small number of cases. We therefore conducted a pooled analysis of 14 case-control studies on lung cancer in Caucasian non-smokers with comparable information on genetic polymorphisms included in the International Collaborative Study on Genetic Susceptibility to Environmental Carcinogens. We pooled the raw data from a total of 302 cases and 1631 controls with random effects models. We also evaluated the possibility of inclusion bias and conducted influence analyses. The odds ratio (OR) of lung cancer for the variant CYP1A1 Ile(462)Val polymorphism (Ile/Val, Val/Val) was 2.99 [95% confidence interval (95%CI) 1.51-5.91]; this effect was stronger on lung adenocarcinoma (OR 4.85, 95%CI 2.03-11.6). After excluding outlying or imprecise studies, we did not observe a significant effect of the CYP1A1 MspI (T(3801)C) polymorphism or GSTM1 null genotype (OR 1.20, 95%CI 0.89-1.63). Furthermore, our analyses suggested a combined effect of the CYP1A1 Ile(462)Val polymorphism and GSTM1 null genotype. The OR for the combination of the CYP1A1 Ile(462)Val variant and GSTM1 null genotype was 4.67 (95%CI 2.00-10.9) compared with the concurrent presence of the CYP1A1 wild-type and GSTM1 non-null genotype. We did not observe a modification of the effect of the GSTM1 null genotype according to exposure to environmental tobacco smoke and urban/rural residence. Our study therefore suggests that the CYP1A1 Ile(462)Val variant allele might play a role in lung carcinogenesis among non-smokers, possibly in combination with the GSTM1 null genotype.

Case-Control Studies↗
PubMed2000

Molecular investigation of African isolates of Trichinella reveals genetic polymorphism in Trichinella nelsoni.

Molecular genetic studies were carried out on three isolates of Trichinella nelsoni (from Kenya, Tanzania and South Africa) and three isolates of Trichinella T8 (from South Africa and Namibia) from sylvatic carnivores and from a sylvatic swine. A probe (pT7.3) specific for T. nelsoni was obtained by screening a pUC18 genomic library. The pT7.3 sequence was 346 bp in length with an AT content of 70%. The sequence is present approximately 200 times per haploid genome. Southern blot analysis of Hind III digested DNAs of the three isolates of T. nelsoni revealed that the hybridisation patterns of the isolates from Kenya and Tanzania were identical and that they differed from that of the isolate from South Africa, indicating the presence of polymorphism in this species. A pUC18 genomic library of Trichinella T8 was also screened, and one clone (pT8.3) was found to be specific for homologous DNA by dot blot, but Southern blot analysis of DNA samples from eight genotypes showed different hybridisation signals for both Trichinella T8 and Trichinella britovi DNAs. No differences in the nucleotide sequences of the expansion segment V were observed for the T. nelsoni isolates. However, they differed from those of Trichinella T8. The presence of Trichinella T8 in Africa south of the Sahara and its genetic relationship with T. britovi remain unclear and warrant detailed investigations.

Animals↗