Search PubMed⌕ Search

Biomedical subjects

U Gyllensten

Publications and source records attributed to U Gyllensten.

At least 55 records · Page 3Linked to original sources
PubMed1994

PCR-based DNA typing of saliva on stamps and envelopes.

In forensic cases involving mail bombs, extortion, kidnapping or threatening letters, biological evidence such as the saliva used to attach the stamp and seal the envelope could be used for genetic analysis. We have developed a highly sensitive semi-nested PCR method for the HLA-DRB1 locus; suitable for the analyses of very limited amounts of DNA. When applied to a set of stamps and envelopes with saliva from control individuals, typing results were consistent with those obtained using hairs drawn from the same individuals. No interference was found due to DNA from the fingerprints of people handling the letters. The system was applied to three forensic cases with threatening letters. The first case resulted in an exclusion of the suspect. In the second case, the suspect could not be excluded (probability of identical genotype by chance > 0.01). These results demonstrate that biological evidence in cases with threatening letters is amenable to genetic typing.

Base Sequence↗
PubMed1993

Association of insulin-dependent diabetes mellitus in Taiwan with HLA class II DQB1 and DRB1 alleles.

The allelic constitution at HLA class II DRB1, DQB1, DQA1, and DPB1 loci of IDDM patients from Taiwan was compared with that of ethnically matched nondiabetic individuals by PCR-based DNA typing. Of the three haplotypes found to be positively associated with IDDM in Taiwan, two (DRB1*0301-DQA1*0501-DQB1*0201 and DR4-DQA1*0301-DQB1*0302) appear to be identical to the susceptible haplotypes in Caucasian and black populations, whereas the third haplotype (DR4-DQA1*0301-DQB1*04) has been reported to be positively associated with IDDM only in the Japanese population. The three haplotypes, DRB1*1502-DQA1*0102-DQB1*0601 and DRB1*1201 (or 1202)-DQA1*0501-DQB1*0301 and DRB1*0803-DQA1*0103-DQB1*0601, were negatively associated with IDDM in Taiwan; a protective effect of the last haplotype has not been reported previously. Neither DQ beta non-Asp-57 nor DQA1*0301 alone appears sufficient to account for the HLA-associated susceptibility to IDDM in Taiwan. Also, the DQ alpha beta heterodimer encoded by the alleles DQA1*0301/DQB1*0201, DQA1*0301/DQB1*0302, or DQA1*0501/DQB1*0201 does not explain the susceptibility of a larger fraction of the IDDM patients than the residue at position 57 of the DQ beta chain or DQA1*0301. Finally, the DRB1 alleles appear to affect IDDM susceptibility, although for most haplotypes the effect of individual loci cannot be assessed due to the linkage disequilibrium between the DQ and the DR region.

Adult↗
PubMed1993

Intrafamilial variation in Leber hereditary optic neuropathy revealed by direct mutation analysis.

Leber hereditary optic neuropathy (LHON) has been associated with a mitochondrial mutation at position 11,778 in the ND4 gene in about 50% of families. Individuals from six Swedish families with LHON were investigated for the presence of this mutation using allele-specific oligonucleotides and a sensitive chemoluminescent detection system. The point mutation was seen in mitochondrial DNA extracted from leukocytes in five families, four of which showed a homoplasmic pattern. One family showed a heteroplasmic pattern and one family was negative for the mutation. Six adults without impaired vision from three LHON families were detected as carriers with a degree of mutated mitochondrial DNA similar to that in affected relatives. The results show that the penetrance of LHON varies remarkably among carriers of the 11,778 mutation within families. We conclude that the prognosis for carriers should be stated cautiously when interpreting results from mutation analysis of mitochondrial DNA in leukocytes.

Adult↗
PubMed1993

Genetic typing of HLA class II genes in Swedish populations: application to forensic analysis.

In an attempt to determine the value of DNA based typing of HLA class II loci to forensic analysis, allele and genotype frequencies at DQA1, DQB1, DPB1, and DRB1 were determined in samples from two Swedish populations using hybridization with sequence specific oligonucleotides to PCR amplified DNA. Significant allele frequency differences were observed at the DQB1 and DRB1 loci between the two populations, as well as between one of the Swedish and a Norwegian population. The average heterozygosity varies between 0.74 to 0.91 and the power of discrimination between 0.90 to 0.98, with the highest values obtained for the DRB1 locus. The probability of genotype identity by chance differs on average 2% between the populations. When applied to a paternity case with one parent deceased and a criminal case, typing of class II loci proved in both cases informative. Analyses of DR and DQ genes does not increase the power of discrimination, due to strong linkage, but offers through the reconstruction of putative haplotypes an internal control for the consistency of the typing results at several loci. Typing of the DRB1 and DPB1 loci was found to result in an approximate combined average probability of genotype identity by chance of one in a thousand.

Alleles↗
PubMed1992

Low incidence of human papillomavirus type 16 DNA in bladder tumor detected by the polymerase chain reaction.

Human papillomavirus (HPV) detection was done using the polymerase chain reaction technique on tumor tissue from 44 patients with transitional cell carcinoma of the urinary bladder. Only one of the 44 was associated with HPV infection. The HPV-positive patient was not known to have immunodeficiency or genital warts, and the tumor was not morphologically different from the other tumors. Control experiments excluded the possibility that this finding was caused by contamination of the sample. This study confirms that HPV infection is a rare condition in bladder carcinoma.

Carcinoma, Transitional Cell↗
PubMed1991

Paternal inheritance of mitochondrial DNA in mice.

For nearly 20 years it has been assumed on the basis of low-resolution experiments that mitochondrial (mt)DNA, in contrast to the genes in the nucleus, has an exclusively maternal mode of inheritance in animals. Using the polymerase chain reaction, paternally inherited mtDNA molecules have now been detected in mice at a frequency of 10(-4), relative to the maternal contributions. These mice were hybrids between two inbred strains (C57BL/6J and Mus spretus) whose mtDNAs can be distinguished easily. This new mode of inheritance provides a mechanism for generating heteroplasmy and may explain mitochondrial disorders exhibiting biparental transmission.

Animals↗
PubMed1991

Genetic diversity at class II DRB loci of the primate MHC.

The evolution of polymorphism at loci encoding the beta-chains of the MHC class II DR Ag was studied in primates by DNA amplification (polymerase chain reaction). Phylogenetic analysis of 63 DRB sequences from the polymorphic second exon (first domain) of nonhuman primates and 53 human sequences indicates the presence of five DRB loci in primates, derived from a DRB1-like ancestral locus over 20 million yr ago. Many of the allelic types at the DRB1 locus predate the divergence of hominoids (5 million yr ago) and some (DR4, DR3, 5, 6) predate the divergence of Old world monkeys and hominoids (20 million yr ago). The DRB3 locus appears to have arisen before the divergence of hominoids on an ancestral DRB1 lineage. The DRB2 and DRB5 loci were generated more than 20 million yr ago and the DRB4 locus more than 5 million yr ago. The DRB2 locus, a pseudogene in humans, is polymorphic in the nonhuman primates.

Amino Acid Sequence↗
PubMed1988

HLA class II allelic variation and susceptibility to pemphigus vulgaris.

The autoimmune dermatologic disease pemphigus vulgaris (PV) is associated with the HLA serotypes DR4 and DRw6. Susceptibility to PV could be conferred either by sequences shared between the DR4 and DRw6 haplotypes or by different sequences in these haplotypes. We have examined the distribution of DR and DQ beta-chain and DQ alpha-chain alleles in PV patients and in control subjects by hybridization with oligonucleotide probes and sequence analysis of in vitro amplified DNA. Ninety percent (34/38) of the DR4 haplotypes in patients contain a specific DR beta I sequence present in 36% (16 of 44) of DR4 controls (P = 0.001). This sequence is also found in DRw6 haplotypes. However, it is present in only 25% (6 of 24) of DRw6 patients. The results of our analysis indicate that predisposition to PV is conferred by different sequences in DR4 and DRw6 haplotypes. The DR4 susceptibility is highly associated with the Dw10 DR beta I allele, implicating the polymorphic residues in the third hypervariable region. The DRw6 susceptibility is strongly associated with a rare DQ beta allele (DQB1.3). This allele differs from a common DQ beta allele (DQB1.1) only by a valine----aspartic acid substitution at position 57.

Alleles↗
PubMed1985

Introgression between two cutthroat trout subspecies with substantial karyotypic, nuclear and mitochondrial genomic divergence.

The authors used allozymes encoded by nuclear genes and restriction enzyme analysis of mitochondrial DNA (mtDNA) to study secondary contact between westslope (Salmo clarki lewisi) and Yellowstone cutthroat trout (Salmo clarki bouvieri) in Forest Lake, Montana. Eleven diagnostic allozyme loci identified this as a random-mating hybrid swarm. No parental, first-generation hybrid or backcross genotypes were detected in the sample (N = 33), and genotype distributions at all the variable loci conform to binomial expectations. There is little linkage disequilibrium between the diagnostic loci, indicating that the nuclear genomes of the two subspecies are largely randomly associated. The allozymes and mtDNA give identical estimates of the proportional genetic contribution of each subspecies. Thus, males and females from both subspecies have contributed equally to this hybrid swarm. Although these subspecies have accumulated substantial genetic divergence between their nuclear (Nei's D = 0.34) and mitochondrial (2% sequence divergence) genomes, this has not resulted in a genetic barrier to exchange between them.

Alleles↗
PubMedDate not supplied

Analysis of the complete human mtDNA genome: methodology and inferences for human evolution.

The analysis of mitochondrial DNA (mtDNA) sequences has been a potent tool in our understanding of human evolution. However, almost all studies of human evolution based on mtDNA sequencing have focused on the control region, which constitutes less than 7% of the mitochondrial genome. The rapid development of technology for automated DNA sequencing has made it possible to study the complete mtDNA genomes in large numbers of individuals, opening the field of mitochondrial population genomics. Here we describe a suitable methodology for determining the complete human mitochondrial sequence and the global mtDNA diversity in humans. Also, we discuss the implications of the results with respect to the different hypotheses for the evolution of modern humans.

Biological Evolution↗