No abstract

We report a dinucleotide repeat polymorphism in the 3' area of the mitochondrial control region. The fragments obtained using a new primer set could be reliably separated by polyacrylamide gel electrophoresis (PAGE) using nondenaturing gels. A total of five alleles [(CA)3 to (CA)7] were detected on silver-stained gels. The 90 bp product corresponds to allele 5. Samples from one African and three European populations were characterized. Significant differences could be demonstrated as to the incidence of single alleles and allele distributions in different populations. These differences were found between the three European and one African Bantu population. For specific forensic questions the mitochondrial CA repeat is well suited. Gene diversities in populations of Germany, Hungary, the Russian Federation and Cameroon were 0.36, 0.40, 0.34, 0.52, respectively.

No abstract

Results-DiVerences were found between organs or groups of organs within subjects, pointing towards somatic segregation of mtDNA. In addition, marked diVerences of this organ distribution occurred between subjects, which cannot be explained by tissue specific selection. Conclusions-The observed interperson diVerences can be explained by somatic segregation, which occurs randomly at various developmental stages. Besides tissue specific selection, this process might participate in the distribution of pathogenic mtDNA mutations. (J Med Genet 2001;38:312-317)

The aim of this study was the determination of D‐loop heteroplasmy in astrocytic brain tumors. DNA fragments corresponding to the hypervariable region 2 of the mitochondrial displacement loop (D‐loop) from 12 astrocytic tumors and 2 corresponding brain samples were cloned into a plasmid vector. Heteroduplex analysis revealed high sequence variability in the brain samples and a subfraction of grade 2 and grade 3 tumors. Furthermore, the results were suggestive of a very low degree of heteroplasmy in all glioblastomas. This was confirmed by direct sequencing of 223 cloned DNA samples from nine individuals. Heteroplasmy was caused in most cases by a well‐known length polymorphism of a homopolymeric c‐tract. Heteroplasmy of the two reference brain samples was lost in the corresponding tumors. Genes Chromosomes Cancer 26:80–83, 1999. © 1999 Wiley‐Liss, Inc.