RESUMO
The aim of the present study was to investigate the N-terminal part (the translated part of exon 1) of the human thyrotropin receptor (TSHR) for the presence of mutations. Patients with Graves' disease (n = 160) and healthy controls (blood donors; n = 140) were screened using single-stranded conformational polymorphism (SSCP) in combination with restriction enzyme digestion for the two previously known mutations in this part of the receptor, viz. D36H and P52T TSHR-variants. We did not find any novel mutation in this region. However, D36H and P52T variants were found both in the TSHR of Graves' patients and in the healthy controls. The overall frequency of the D36H-receptor variant was 5.0% (15/300) and of the P52T-receptor, 7.3% (22/300). There was no major difference in the frequency for either of the TSHR alleles between the 2 groups. Thus, these 2 polymorphic variants of the TSHR seem to occur in a relatively high frequency in the population.
Assuntos
Receptores da Tireotropina/genética , Alelos , Substituição de Aminoácidos , Ácido Aspártico/genética , Éxons , Feminino , Frequência do Gene , Testes Genéticos , Doença de Graves/genética , Heterozigoto , Histidina/genética , Humanos , Masculino , Mutação , Polimorfismo Conformacional de Fita Simples , Prolina/genética , Mapeamento por Restrição , Treonina/genéticaRESUMO
Mitochondrial DNA sequences from 74 Swiss individuals were compared to sequences from British and Finish populations. We found that the nucleotide sequence differences between these populations are almost as low as those within the populations. This is in contrast to three African populations, which display substantial differences between each other. The homogeneity of the mitochondrial gene pool in Europe suggests a recent common ancestry for European populations. This may reflect the arrival of anatomically modern humans about 40,000-30,000 years ago or, alternatively, the spread of agriculturalists about 10,000-6,000 years ago. Taking into account the estimated rate of evolution of the mitochondrial control region, the data favor the former explanation.
Assuntos
População Negra/genética , DNA Mitocondrial/genética , Variação Genética , População Branca/genética , DNA Mitocondrial/química , Finlândia , Humanos , Homologia de Sequência do Ácido Nucleico , Suíça , Reino UnidoRESUMO
An approximately 5000-year-old mummified human body was recently found in the Tyrolean Alps. The DNA from tissue samples of this Late Neolithic individual, the so-called "Ice Man," has been extracted and analyzed. The number of DNA molecules surviving in the tissue was on the order of 10 genome equivalents per gram of tissue, which meant the only multi-copy sequences could be analyzed. The degradation of the DNA made the enzymatic amplification of mitochondrial DNA fragments of more than 100 to 200 base pairs difficult. One DNA sequence of a hypervariable segment of the mitochondrial control region was determined independently in two different laboratories from internal samples of the body. This sequence showed that the mitochondrial type of the Ice Man fits into the genetic variation of contemporary Europeans and that it was most closely related to mitochondrial types determined from central and northern European populations.
