![mtcn number example mtcn number example](https://trustfundshackersonline.files.wordpress.com/2019/07/1fc5fe49-46a7-4f62-ab06-440f26eab25a-341-000000565ad014c0.jpg)
The human mt genome is usually present in several copies per mitochondrion and the total number of mtDNA copies per cell varies greatly between different individuals and different tissues of the same individual. In addition to tRNA and rRNA genes, the mt genome harbors 13 genes encoding proteins of the respiratory chain. While most human mt proteins are encoded in the nuclear genome and imported to the mitochondrion following translation, mitochondria also contain their own genome. Mitochondria are the central cellular structures for energy production. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All relevant data are within the paper and its Supporting Information files.įunding: This research was funded by Max Planck Society. Received: OctoAccepted: FebruPublished: March 15, 2016Ĭopyright: © 2016 Wachsmuth et al.
![mtcn number example mtcn number example](https://1.bp.blogspot.com/-M_Wr3pFh2Tw/X-q6LDx_3SI/AAAAAAAAqLw/VUCvgPiCMzs-yVbXsxl64fLB3--6G_-FQCLcBGAsYHQ/s1542/Screen%2BShot%2B2020-12-29%2Bat%2B1.09.05%2BPM.png)
Williams, Case Western Reserve University School of Medicine, UNITED STATES As both sites are part of functional elements required for regulation of mtDNA replication, we suggest that selection may be acting via increasing heteroplasmy to reduce mtCN during aging.Ĭitation: Wachsmuth M, Hübner A, Li M, Madea B, Stoneking M (2016) Age-Related and Heteroplasmy-Related Variation in Human mtDNA Copy Number. Linear and partial regression analyses of mtCN with heteroplasmy (determined in a previous study of these same samples) revealed that the decrease of mtCN in skeletal muscle is mainly correlated with an increasing total number of heteroplasmic sites, and with increasing minor allele frequency at two sites (47), that are heteroplasmic almost exclusively in skeletal muscle. Heteroplasmy refers to intra-individual differences in the sequence of the mtDNA genome and heteroplasmic mutations accumulate during aging. Overall, mtCNs of different tissues within an individual are mainly independent of each other, indicating that tissue-specific rather than individual-specific processes largely influence mtCN. We estimated mtDNA copy number (mtCN) in 12 different tissues of 152 individuals applying three different methods, and found age-related variation for two tissues: mtCN in skeletal muscle is negatively correlated with age (especially in males) while mtCN in liver is positively correlated with age. The total number of mitochondrial genomes in a human cell differs between individuals and between the tissues of a single individual however the factors that influence this variation remain unknown. These data support the hypothesis that selection acting on these heteroplasmic sites is reducing mtCN in SM of older individuals. Heteroplasmies at both sites are highly specific for SM, accumulate with aging and are part of functional elements that regulate mtDNA replication. MtCN in SM samples was significantly negatively correlated with both the total number of heteroplasmic sites and with minor allele frequency (MAF) at two heteroplasmic sites, 47. Skeletal muscle (SM) samples showed an age-related decrease in mtCN that was especially pronounced in males, while there was an age-related increase in mtCN for liver (LIV) samples. Hence, each tissue of an individual seems to regulate mtCN in a tissue-related rather than an individual-dependent manner. Comparisons of mtCN from different tissues of the same individual revealed that mtCNs in different tissues are, with few exceptions, uncorrelated. However, capture-enrichment data provide reliable estimates of relative (albeit not absolute) mtCNs. The highest precision in mtCN estimation was achieved using shotgun sequencing data. Three different methods to estimate mtCN were compared: shotgun sequencing (in 4 tissues), capture-enriched sequencing (in 12 tissues) and droplet digital PCR (ddPCR, in 2 tissues). This study investigates variation in mtDNA copy numbers (mtCN) in 12 different tissues obtained at autopsy from 152 individuals (ranging in age from 3 days to 96 years). Recent studies found that heteroplasmies are highly tissue-specific, site-specific, and allele-specific, however the functional implications have not been explored. The mitochondrial (mt) genome is present in many copies in human cells, and intra-individual variation in mtDNA sequences is known as heteroplasmy.