RESUMO
Data have been collected from 602 Caucasians, 190 Afro-Caribbeans and 257 Asians of Indo/Pakistani descent who have been profiled using a new six locus short tandem repeat (STR) multiplex. The data have been analysed by conventional significance testing methods: the exact test, homozygosity, and conventional goodness of fit to Hardy-Weinberg proportions. Frequency tables are given and the expected performance in British forensic casework is discussed.(AU)
Assuntos
Estudo Comparativo , Humanos , Etnicidade/genética , Marcadores Genéticos/genética , Sequências Repetitivas de Ácido Nucleico/genética , Homozigoto , Modelos Genéticos , Probabilidade , Mapeamento Cromossômico , Frequência do Gene , Genética Populacional , Genótipo , Triagem de Portadores GenéticosRESUMO
A non-progressive recessive cerebellar ataxia was identified in a highly inbred Cayman island population. Cayman cerebellar ataxia is characterized by marked psychomtor retardation, and prominent cerebellar dysfunction manifested by nystagmus, intention tremor, dysarthric speech, and an ataxic gait. In this study, we identify to chromosome 19p 13.3 using pooled DNA samples of affected individuals from an isolated population as PCR template for a genome wide screen with short tandem repeat markers. Our data demonstrate that the DNA pooling approach to identify disease gene loci is feasible using individuals from isolated populations in which kindred relationship are highly complex and exact relationships between all affected individuals are not known. Genetic fine mapping demonstrates that the genetic disease interval is approximately 9 cM, but contained within a small physical region. The existence of multiple individuals that are recombinant with flanking markers indicates that the disease interval can be further narrowed with additional markers. (AU)
Assuntos
Humanos , Ataxia Cerebelar/genética , Ataxia Cerebelar/epidemiologia , DNA/genética , Região do Caribe/epidemiologia , Mapeamento Cromossômico , Doenças Genéticas InatasRESUMO
R-plasmids RP4 and its derivatives were transferred from Escherichia coli to two cowpea rhizobia strains. The frequency of RP4 transfer in cowpea rhizobia strain JRC23-SM20 and IRC256-HA409 was 1,000 fold higher than transfer frequency of R68.45. The transconjugants were further used to transfer R-plasmids within (isogenic) and between (non-isogenic cowpea rhizobia strains. The plasmid transfer frequency was higher in isogenic than non-isogenic strains. The ability of R-plasmids to mobilize chromosomal genes in cowpea rhizobia was also examined. R-plasmids mediated the chromosomal transfer; however, mobilization of chromosomal maker Sm and Met+ by RP4 in isogenic strains was more efficient than by R68.45. Chromosomal mobilization has not previously been reported in cowpea rhizobia (AU)
Assuntos
Técnicas In Vitro , Rhizobiaceae/genética , Mapeamento Cromossômico , Fatores R , Resistência Microbiana a MedicamentosRESUMO
We have studied the interaction of the OOO/OO gene arrangements with various á globin genotypes (AA, AS, AC, SS and SC). Whereas this interaction has no detectable clinical or haematological effects in subjects with AA, SS or SC genotypes it is associated with a significantly increased level of Hb S or Hb C in heterozygotes for these variants. These findings indicate that the additional O globin gene in the OOO gene arrangement is functional (Summary)
Assuntos
Humanos , Criança , Adolescente , Adulto , Masculino , Feminino , Globinas/genética , Hemoglobina Falciforme , Anemia Falciforme/sangue , Anemia Falciforme/genética , Mapeamento Cromossômico , Enzimas de Restrição do DNA , Genótipo , Hemoglobina C/análise , Doença da Hemoglobina SC/sangue , Doença da Hemoglobina SC/genética , Hemoglobina Falciforme/análise , Heterozigoto , HomozigotoRESUMO
We have studied seven Jamaican Negro families in whom the genes for O thalassaemia and the sickle cell mutation (ás) were independently segretated. Using a combination of techniques we identified two O thalassaemia phenotypes which resemble the reserve (O thalassaemia 1) and mild (O thalassaemia 2) determinants previously described in Orientals. This study has enabled us to clearly correlate the phenotype of O thalassaemia with the genotype in this population. Furthermore, since in each family O thalassaemia was present in association with the gene for the sickle cell mutation we have determined the proportion of Hb S in the peripheral blood of individuals with the OO/OO, -O/-O genotype who are also heterozygous for the ás mutation. Genetic analysis in these families shows that in each case subjects with the O thalassaemia 1 phenotype are homozygous for the O thalassaemia 2 defect (-O/-O). We have found no instances of the genotype --/OO in this population which may explain the rarity of the severe O thalassaemia 2 homozygotes from this population shows that the (-O/) haplotype results from a deletion of one of the linked pair of O globin and that this had probably arisen by an unequal crossover between non-homologous O genes (AU)
