mtDB: Human Mitochondrial Genome Database, a resource for population genetics and medical sciences

The mitochondrial genome, contained in the subcellular mitochondrial network, encodes a small number of peptides pivotal for cellular energy production. Mitochondrial genes are highly polymorphic and cataloguing existing variation is of interest for medical scientists involved in the identification of mutations causing mitochondrial dysfunction, as well as for population genetics studies. Human Mitochondrial Genome Database (mtDB) (http://www.genpat.uu.se/mtDB) has provided a comprehensive database of complete human mitochondrial genomes since early 2000. At this time, owing to an increase in the number of published complete human mitochondrial genome sequences, it became necessary to provide a web-based database of human whole genome and complete coding region sequences. As of August 2005 this database contains 2104 sequences (1544 complete genome and 560 coding region) available to download or search for specific polymorphisms. Of special interest to medical researchers and population geneticists evaluating specific positions is a complete list of (currently 3311) mitochondrial polymorphisms among these sequences. Recent expansions in the capabilities of mtDB include a haplotype search function and the ability to identify and download sequences carrying particular variant

mtDB: Human Mitochondrial Genome Database, a resource for population genetics and medical sciences

The mitochondrial genome, contained in the subcellular mitochondrial network, encodes a small number of peptides pivotal for cellular energy production. Mitochondrial genes are highly polymorphic and cataloguing existing variation is of interest for medical scientists involved in the identification of mutations causing mitochondrial dysfunction, as well as for population genetics studies. Human Mitochondrial Genome Database (mtDB) () has provided a comprehensive database of complete human mitochondrial genomes since early 2000. At this time, owing to an increase in the number of published complete human mitochondrial genome sequences, it became necessary to provide a web-based database of human whole genome and complete coding region sequences. As of August 2005 this database contains 2104 sequences (1544 complete genome and 560 coding region) available to download or search for specific polymorphisms. Of special interest to medical researchers and population geneticists evaluating specific positions is a complete list of (currently 3311) mitochondrial polymorphisms among these sequences. Recent expansions in the capabilities of mtDB include a haplotype search function and the ability to identify and download sequences carrying particular variants

Lifestyle, Genetics, and Disease in Sami

Aim: To present a summary of the lifestyle, genetic origin, diet, and disease in the population of Sami, indigenous people of northern Fennoscandia. Method: A survey of the available scientific literature and preliminary results from our own study of the Swedish Sami population. Results: The Sami probably have a heterogeneous genetic origin, with a major contribution of continental or Eastern European tribes and a smaller contribution from Asia. The traditional Sami diet, high in animal products, persists in Sami groups still involved with reindeer herding, but others have adopted a diet typical of Western cultures. Early reports indicated a lower prevalence of heart disease and most cancers, except stomach cancer. Recent studies have not found a lower risk of heart disease, but have consistently shown an overall reduced cancer risk. Sami have been reported to share some specific health-related genetic polymorphisms with other European populations, but none that would explain the observed differences in disease risk. Conclusion: The genetic structure of the Sami population makes it suitable for studies of the genetic and environmental factors influencing the development of common diseases. The difference in incidence of heart disease between studies may reflect the ongoing transition from a traditional to a more Westernized lifestyle. The ability to compare population segments with different lifestyles, combined with the genetic structure of the population, creates unusual possibilities for studies of the genetic and environmental factors involved in the development of common disease

Lifestyle, Genetics, and Disease in Sami

Aim: To present a summary of the lifestyle, genetic origin, diet, and disease in the population of Sami, indigenous people of northern Fennoscandia. Method: A survey of the available scientific literature and preliminary results from our own study of the Swedish Sami population. Results: The Sami probably have a heterogeneous genetic origin, with a major contribution of continental or Eastern European tribes and a smaller contribution from Asia. The traditional Sami diet, high in animal products, persists in Sami groups still involved with reindeer herding, but others have adopted a diet typical of Western cultures. Early reports indicated a lower prevalence of heart disease and most cancers, except stomach cancer. Recent studies have not found a lower risk of heart disease, but have consistently shown an overall reduced cancer risk. Sami have been reported to share some specific health-related genetic polymorphisms with other European populations, but none that would explain the observed differences in disease risk. Conclusion: The genetic structure of the Sami population makes it suitable for studies of the genetic and environmental factors influencing the development of common diseases. The difference in incidence of heart disease between studies may reflect the ongoing transition from a traditional to a more Westernized lifestyle. The ability to compare population segments with different lifestyles, combined with the genetic structure of the population, creates unusual possibilities for studies of the genetic and environmental factors involved in the development of common disease

Healing in the Sámi North

There is a special emphasis today on integrating traditional healing within health services. However, most areas in which there is a system of traditional healing have undergone colonization and a number of pressures suppressing tradition for hundreds of years. The question arises as to how one can understand today’s tradition in light of earlier traditions. This article is based on material collected in Sámi areas of Finnmark and Nord-Troms Norway; it compares local healing traditions with what is known of earlier shamanic traditions in the area. The study is based on 27 interviews among healers and their patients. The findings suggest that although local healing traditions among the Sámi in northern Norway have undergone major transformations during the last several hundred years, they may be considered an extension of a long-standing tradition with deep roots in the region. Of special interest are also the new forms tradition may take in today’s changing global society

Mitochondria and Human Evolution

Mitochondrial DNA (mtDNA) has been a potent tool in studies of the evolution of modern humans, human migrations and the dynamics of human populations over time. The popularity of this cytoplasmic genome has largely been due to its clonal inheritance (in Man) allowing the tracing of a direct genetic line. In addition, a comparatively high rate of nucleotide substitution facilitates phylogenetic resolution among relatively closely related individuals of the same species. In this thesis, a statistically supported phylogeny based on complete mitochondrial genome sequences is presented which, for the first time, unambiguously places the root of modern human mitochondrial lineages in Africa in the last 200 thousand years. This conclusion provides strong support for the “recent African origin” hypothesis. Also, the complete genome data underline the problematic nature of traditional approaches to analyses of mitochondrial phylogenies. The dispersal of anatomically modern humans from the African continent is examined through single nucleotide polymorphism (SNP) and sequence data. These data imply an expansion from Africa about 57 thousand years ago and a subsequent population dispersal into Asia. The dispersal coincides with a major population division that may be the result of multiple migratory routes to East Asia. Also investigated is the question of a common origin for the indigenous peoples of Australia and New Guinea. Previous studies have been equivocal on this question with some presenting evidence for a common genetic origin and other proposing separate histories. Our data reveals an ancient genetic link between Australian Aborigines and the peoples of the New Guinea highlands

Ultra-deep sequencing of mouse mitochondrial DNA: mutational patterns and their origins

Somatic mutations of mtDNA are implicated in the aging process, but there is no universally accepted method for their accurate quantification. We have used ultra-deep sequencing to study genome-wide mtDNA mutation load in the liver of normally- and prematurely-aging mice. Mice that are homozygous for an allele expressing a proof-reading–deficient mtDNA polymerase (mtDNA mutator mice) have 10-times-higher point mutation loads than their wildtype siblings. In addition, the mtDNA mutator mice have increased levels of a truncated linear mtDNA molecule, resulting in decreased sequence coverage in the deleted region. In contrast, circular mtDNA molecules with large deletions occur at extremely low frequencies in mtDNA mutator mice and can therefore not drive the premature aging phenotype. Sequence analysis shows that the main proportion of the mutation load in heterozygous mtDNA mutator mice and their wildtype siblings is inherited from their heterozygous mothers consistent with germline transmission. We found no increase in levels of point mutations or deletions in wildtype C57Bl/6N mice with increasing age, thus questioning the causative role of these changes in aging. In addition, there was no increased frequency of transversion mutations with time in any of the studied genotypes, arguing against oxidative damage as a major cause of mtDNA mutations. Our results from studies of mice thus indicate that most somatic mtDNA mutations occur as replication errors during development and do not result from damage accumulation i