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Principles of Biology
Published in Arthur T. Johnson, Biology for Engineers, 2019
Mitochondria in the cell carry their own DNA separate from that in the cell nucleus. Sperm of all animal species contain their mitochondria in their tails, Ih are separated from their heads at the moment of fertilization. Thus, the newly fertilized egg contains mitochondrial DNA from the female parent only. Tracing relatives through the female lineage is thus relatively simple. Mitochondrial DNA (mtDNA) suffers a higher rate of mutation compared to nuclear DNA due to factors such as proximity to highly reactive free radicals, lack of histone protection, and poor fidelity of mtDNA replication and repair. Because of this, differences in mtDNA can be used to study relationships among population groups. Knowing the rate at which spontaneous genetic mutation occurs can be used to estimate the ages of different species.
Innovations in Noninvasive Instrumentation and Measurements
Published in Robert B. Northrop, Non-Invasive Instrumentation and Measurement in Medical Diagnosis, 2017
For some types of cancer, the body's immune system (IS) recognizes the tumor as foreign tissue early in its growth because of abnormal damaged or mutated cancer cell surface proteins, and the IS mounts an attack on the tumor cells. The attack may prove ineffectual because the tumor grows faster than the IS can fight it, or the tumor cells may secrete substances that suppress IS's actions. Still, there will be circulating antibodies (Abs) in the blood against signature tumor cell surface proteins. The problem is to detect these Abs and use them as a sign that a particular type of cancer is growing in an otherwise asymptomatic body. The mitochondrial DNA (mtDNA) of cancer cells may also be mutated, and can serve as a basis for cancer detection. The use of mtDNA to identify cancers in the normal latency period is described below.
Nanoparticles and Viruses as Mitophagy Inducers in Immune Cells
Published in Bertrand Henri Rihn, Biomedical Application of Nanoparticles, 2017
Housam Eidi, Zahra Doumandji, Lucija Tomljenovic, Bertrand Henri Rihn
Several molecules could be nano-delivered to the mitochondria, such as RNA or DNA (e.g., antisense oligonucleotides, ribozymes, and plasmid DNA expressing mitochondrial genes), an approach that may be relevant for the treatment of mitochondrial DNA diseases (Sakhrani and Padh 2013). One of these treatment strategies could be the delivery of antioxidant and proapoptotic drugs to mitochondria to protect them from oxidative stress and to trigger apoptotic cell death in tumor cells, respectively. Additionally, delivery of proteins and peptides to mitochondria could be also included in these treatment strategies for several mitochondrial disorders (Gruber et al. 2013, Weissig et al. 2004).
Developing mitochondrial DNA field-compatible tests
Published in Critical Reviews in Environmental Science and Technology, 2022
Bidhan C. Dhar, Christina E. Roche, Jay F. Levine
Mitochondria are fundamental organelles of most eukaryotic cells and mitochondrial DNA (mtDNA) plays a significant role in cell digestion, apoptosis, oxidative phosphorylation, fatty acid oxidation, amino acid biosynthesis, and overall homeostasis (Bonawitz et al., 2006; Maechler & Wollheim, 2001; Wallace et al., 1999). Most of the approximate 1100 human cellular genes that encode proteins are nuclear DNA (nDNA). However, 37 genes are mtDNA (Maechler & Wollheim, 2001). Mitochondrial DNA are twofold symmetrical molecules and most mitochondrial genomes house 13 polypeptides, two ribosomal RNA (12S rRNA and 16S rRNA) and 22 transfer RNA (tRNA) encoding sequences. Some mitochondrial protein coding genes are building blocks for cellular function and respiration, such as adenosine triphosphate (ATP), while others like cytochrome oxidase (COX) also play a role in immune response. Although genes are similar across organisms, mitochondrial genome size can vary greatly from organism to organism, more than 10,000 base pairs (bp) in many invertebrates and mammals (e.g. 13,000 bp in annelids, 16,000 bp in mammals) and from 1100 bp to 2 Mbp in the plant and fungi kingdoms (National Center for Biotechnology, 2004).
Genetic ethics and mtDNA replacement techniques
Published in The New Bioethics, 2021
Moreover, mtDNA replacement therapies can provide another option for women experiencing infertility. Recent studies have shown that factors within the cytoplasm of the oocyte are important for embryonic development and may be linked to certain fertility barriers (Gómez-Tatay et al.2017). Studies have also shown that an increase in reactive oxygen species levels leads to a decrease in metabolic function and energy production which causes greater mutations in the mitochondrial DNA (Reznichenko et al.2016). Replacement techniques could allow women to overcome infertility issues by introducing healthy cytoplasm and mitochondria to an oocyte, ultimately increasing the chances for a woman to conceive a healthy child (Reznichenko et al.2016). While these techniques being used to treat infertility do present their own set of challenges, it’s important to highlight that mtDNA replacement may provide application beyond the treatment of diseases, thus highlighting the need for additional clinical trials.
Genome Modifying Reproductive Procedures and their Effects on Numerical Identity
Published in The New Bioethics, 2019
Mitochondrial disorders arise when genetic mutations in the mitochondrial DNA (or in the nuclear chromosomes) limit the energy supply in cells giving rise to dysfunctions in multiple organs and tissues especially those with high energy requirements such as in the brain or muscles.