Heterogeneous geographic patterns of nucleotide sequence diversity between two alcohol dehydrogenase genes in wild barley (Hordeum vulgare subspecies spontaneum).
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Patterns of nucleotide sequence diversity in the predominantly self-fertilizing species Hordeum vulgare subspecies spontaneum (wild barley) are compared between the putative alcohol dehydrogenase 3 locus (denoted "adh3") and alcohol dehydrogenase 1 (adh1), two related but unlinked loci. The data consist of a sequence sample of 1,873 bp of "adh3" drawn from 25 accessions that span the species range. There were 104 polymorphic sites in the sequenced region of "adh3." The data reveal a strong geographic pattern of diversity at "adh3" despite geographic uniformity at adh1. Moreover, levels of nucleotide sequence diversity differ by nearly an order of magnitude between the two loci. Genealogical analysis resolved two distinct clusters of "adh3" alleles (dimorphic sequence types) that coalesce roughly 3 million years ago. One type consists of accessions from the Middle East, and the other consists of accessions predominantly from the Near East. The two "adh3" sequence types are characterized by a high level of differentiation between clusters ( approximately 2.2%), which induces an overall excess of intermediate frequency variants in the pooled sample. Finally, there is evidence of intralocus recombination in the "adh3" data, despite the high level of self-fertilization characteristic of wild barley. (+info)
Distinctive genetic signatures in the Libyan Jews.
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Unlinked autosomal microsatellites in six Jewish and two non-Jewish populations were genotyped, and the relationships among these populations were explored. Based on considerations of clustering, pairwise population differentiation, and genetic distance, we found that the Libyan Jewish group retains genetic signatures distinguishable from those of the other populations, in agreement with some historical records on the relative isolation of this community. Our methods also identified evidence of some similarity between Ethiopian and Yemenite Jews, reflecting possible migration in the Red Sea region. We suggest that high-resolution statistical methods that use individual multilocus genotypes may make it practical to distinguish related populations of extremely recent common ancestry. (+info)
Genetic and mutational analyses of a large multiethnic Bardet-Biedl cohort reveal a minor involvement of BBS6 and delineate the critical intervals of other loci.
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Bardet-Biedl syndrome (BBS) is a rare autosomal recessive disorder characterized primarily by obesity, polydactyly, retinal dystrophy, and renal disease. The significant genetic and clinical heterogeneity of this condition have substantially hindered efforts to positionally clone the numerous BBS genes, because the majority of available pedigrees are small and the disorder cannot be assigned to any of the six known BBS loci. Consequently, the delineation of critical BBS intervals, which would accelerate the discovery of the underlying genetic defect(s), becomes difficult, especially for loci with minor contributions to the syndrome. We have collected a cohort of 163 pedigrees from diverse ethnic backgrounds and have evaluated them for mutations in the recently discovered BBS6 gene (MKKS) on chromosome 20 and for potential assignment of the disorder to any of the other known BBS loci in the human genome. Using a combination of mutational and haplotype analysis, we describe the spectrum of BBS6 alterations that are likely to be pathogenic; propose substantially reduced critical intervals for BBS2, BBS3, and BBS5; and present evidence for the existence of at least one more BBS locus. Our data also suggest that BBS6 is a minor contributor to the syndrome and that some BBS6 alleles may act in conjunction with mutations at other BBS loci to cause or modify the BBS phenotype. (+info)
Epidemiology of antibiotic and heavy metal resistance in bacteria: resistance patterns in staphylococci isolated from populations in Iraq exposed and not exposed to heavy metals or antibiotics.
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Staphylococci were isolated from rural and urban populations in Iraq, which were not known to be exposed to either heavy metals or antibiotics. The antibiotic and heavy metal resistance patterns of these strains were analyzed in both mannitol-fermenting and nonfermenting strains. Over 90% of the strains were resistant to at least one of the following antibiotics: penicillin, chloramphenicol, erythromycin, tetracycline, cephalothin, lincomycin, or methicillin. In general, mannitol-fermenting strains were resistant to penicillin and cupric ions. Mannitol-negative strains were more frequently associated with mercuric ion and tetracycline resistance. Although resistance to penicillin and tetracycline can coexist, the combination of penicillin resistance and tetracycline resistance usually occurred in mannitol-negative strains. The possibility of selection of heavy metal-resistant strains due to exposure to toxic levels of methylmercury was examined. No significant increase in mercuric ion-resistant strains of staphylococci or Escherichia coli were detected in exposed populations as compared to control groups. The possible reasons for this result are discussed. (+info)
Identification of a region in glycoprotein IIIa involved in subunit association with glycoprotein IIb: further lessons from Iraqi-Jewish Glanzmann thrombasthenia.
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The most frequent mutation causing Glanzmann thrombasthenia in Iraqi-Jews (IJ-1) is an 11-bp deletion in exon 13 of the glycoprotein (GP) IIIa gene. This deletion predicts a frameshift that results in the elimination of the C406-C655 disulfide bond and a premature termination codon shortly before the transmembrane domain. To determine the contribution of each of these alterations to the thrombasthenic phenotype, Chinese hamster ovary or baby hamster kidney cells were cotransfected with normal GPIIb complementary DNA (cDNA) and the following GPIIIa cDNAs: normal, cDNA bearing IJ-1 mutation, 2011T>A mutated cDNA predicting C655S (single-letter amino acid codes) substitution, and 2019A>T mutated cDNA predicting Stop657. Elimination of the C406-C655 disulfide bond by C655S substitution did not affect GPIIb/IIIa surface expression or binding of the transfected cells to immobilized fibrinogen, whereas elimination of the transmembrane and cytoplasmic domains in IJ-1 and Stop657 mutants prevented both surface expression and binding of the transfected cells to immobilized fibrinogen. Immunohistochemical staining and immunoprecipitation demonstrated that the elimination of amino acids 657-762 in IJ-1 and Stop657 prevented intracellular GPIIb/IIIa complex formation, and differential immunofluorescence staining of GPIIIa and cellular organelles suggested that the truncated uncomplexed GPIIIa protein was retained in the endoplasmic reticulum. Because the use of GPIIIa Stop693 and normal GPIIb cDNAs yielded GPIIb/IIIa complex formation, though with lower efficiency, it is suggested that amino acids 657-692 of GPIIIa are essential for the intracellular association of GPIIb and GPIIIa. (Blood. 2001;98:1063-1069) (+info)
Ethnicity, self reported psychiatric illness, and intake of psychotropic drugs in five ethnic groups in Sweden.
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STUDY OBJECTIVE: This study hypothesises that the presumed increased risk of self reported longstanding psychiatric illness and intake of psychotropic drugs among Iranian, Chilean, Turkish, and Kurdish adults, when these groups are compared with Polish adults, can be explained by living alone, poor acculturation, unemployment, and low sense of coherence. DESIGN: Data from a national sample of immigrants/refugees, who were between the ages of 20-44 years old, upon their arrival in Sweden between 1980 and 1989. Unconditional logistic regression was used in the statistical modelling. SETTING: Sweden. PARTICIPANTS: 1059 female and 921 male migrants from Iran, Chile, Turkey, Kurdistan and Poland and a random sample of 3001 Swedes, all between the ages of 27-60 years, were interviewed in 1996 by Statistics Sweden. MAIN RESULTS: Compared with Swedes, all immigrants had an increased risk of self reported longstanding psychiatric illness and for intake of psychotropic drugs, with results for the Kurds being non-significant. Compared with Poles, Iranian and Chilean migrants had an increased risk of psychiatric illness, when seen in relation to a model in which adjustment was made for sex and age. The difference became non-significant for Chileans when marital status was taken into account. After including civil status and knowledge of the Swedish language, the increased risks for intake of psychotropic drugs for Chileans and Iranians disappeared. Living alone, poor knowledge of the Swedish language, non-employment, and low sense of coherence were strong risk factors for self reported longstanding psychiatric illness and for intake of psychotropic drugs. Iranian, Chilean, Turkish and Kurdish immigrants more frequently reported living in segregated neighbourhoods and having a greater desire to leave Sweden than their Polish counterparts. CONCLUSION: Evidence substantiates a strong association between ethnicity and self reported longstanding psychiatric illness, as well as intake of psychotropic drugs. This association is weakened by marital status, acculturation status, employment status, and sense of coherence. (+info)
Outcome of living unrelated (commercial) renal transplantation.
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BACKGROUND: Due to inadequate cadaveric and living related organ supply, many end-stage renal disease patients go to Third World countries for commercial transplantation, although the high risk of complications is well established and ethical arguments debate this practice. METHODS: The midterm outcome of 115 patients who had been commercially transplanted in various countries and admitted to our center for post-transplant care and follow-up between 1992 and 1999 was retrospectively analyzed. Data considering the transplantation practice and post-transplant course were collected from the patient files. Outcome of these patients was compared with those with a living related transplant performed at our center. RESULTS: The patients (91 male and 24 female; mean age of 42 +/- 12 years) were transplanted in India (N = 106), Iraq (N = 7), and Iran (N = 2). The mean follow-up period was 64.5 +/- 23.9 months. Post-transplant course was complicated by numerous surgical and/or medical complications, and many of the latter were unconventional infections caused by malaria, invasive fungal infections, and pneumonia due to various opportunistic pathogens. Overall, 52 patients still have functioning allografts, while 22 lost their grafts, 20 died, and 21 were lost to follow-up. Graft survival rates at two, five, and seven years were 84, 66, and 53%, respectively, for the study group, while it was 86, 78, and 73% for living related transplantations performed at our center (P = 0.036). Patient survival rates for the same periods were 90, 80, and 74% for the study group and 90, 85, and 80% for the living related transplantations (P = 0.53). CONCLUSIONS: Besides the ongoing ethical debate, commercial transplantation carries a high risk of unconventional complications, and despite that the patient survival rate is comparable, graft survival is worse than conventional living related transplantations at the midterm. (+info)
Type III 3-methylglutaconic aciduria (optic atrophy plus syndrome, or Costeff optic atrophy syndrome): identification of the OPA3 gene and its founder mutation in Iraqi Jews.
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Type III 3-methylglutaconic aciduria (MGA) (MIM 258501) is a neuro-ophthalmologic syndrome that consists of early-onset bilateral optic atrophy and later-onset spasticity, extrapyramidal dysfunction, and cognitive deficit. Urinary excretion of 3-methylglutaconic acid and of 3-methylglutaric acid is increased. The disorder has been reported in approximately 40 patients of Iraqi Jewish origin, allowing the mapping of the disease to chromosome 19q13.2-q13.3, by linkage analysis. To isolate the causative gene, OPA3, we sequenced four genes within the critical interval and identified, in the intronic sequence of a gene corresponding to cDNA clone FLJ22187, a point mutation that segregated with the type III MGA phenotype. The FLJ22187-cDNA clone, which we identified as the OPA3 gene, consists of two exons and encodes a peptide of 179 amino acid residues. Northern blot analysis revealed a primary transcript of approximately 5.0 kb that was ubiquitously expressed, most prominently in skeletal muscle and kidney. Within the brain, the cerebral cortex, the medulla, the cerebellum, and the frontal lobe, compared to other parts of the brain, had slightly increased expression. The intronic G-->C mutation abolished mRNA expression in fibroblasts from affected patients and was detected in 8 of 85 anonymous Israeli individuals of Iraqi Jewish origin. Milder mutations in OPA3 should be sought in patients with optic atrophy with later onset, even in the absence of additional neurological abnormalities. (+info)