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Genetics
Published in Cathy Laver-Bradbury, Margaret J.J. Thompson, Christopher Gale, Christine M. Hooper, Child and Adolescent Mental Health, 2021
Deoxyribonucleic acid (DNA) is located in the nucleus and mitochondria of the cell. It consists of a sugar-phosphate backbone and four different types of nitrogenous base: adenine, cytosine, thymine and guanine. Each base partner with a complementary base to form base pairs. The DNA molecule itself forms a double helix structure, which is tightly coiled. Nuclear DNA contains approximately 21,000 genes in humans and has been more extensively studied than mitochondrial DNA.
Introduction to lactic acidemias
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
The oxidative phosphorylation system is embedded in the lipid bilayer of the mitochondrial inner membrane. In addition to the five multiprotein enzyme complexes there are two electron carriers – coenzyme Q and cytochrome C. The ATP generated by oxidative phosphorylation may be used in the mitochondrion or transported out by the adenine nucleotide transporter for other cellular purposes. Each of the complexes of the electron transport chain except complex II contains proteins encoded by the mitochondrial DNA, as well as proteins encoded by nuclear DNA (Table 47.1). Mitochondrial DNA and its mutations are maternally inherited; nuclear DNA mutations in this system are inherited autosomally.
Awesome analysis
Published in Brendan Curran, A Terrible Beauty is Born, 2020
At its most basic level, the genetic instructions of nuclear DNA are manifest as the proteins present within the cell. The precise function encoded in a gene is revealed only when the protein for which it codes has been identified. Luckily, the deep-rooted similarity of function in all living organisms means that particular gene sequences encode the same function no matter in which organism they occur – decode the gene function in one organism and you have almost certainly decoded it for them all. Yeast mutants have been generated and studied for decades, so the functions of many of their genes are already well known. This has allowed biologists who have never seen a nematode worm or extracted its DNA to use computer analysis to identify the functions encoded by hundreds of worm genes. They do so simply by calculating how closely a worm gene sequence resembles that of a yeast gene whose function has already been identified using traditional mutation studies.
The mitochondrial DNA control region sequences from the Chinese sui population of southwestern China
Published in Annals of Human Biology, 2021
Yuhang Feng, Hongling Zhang, Qiyan Wang, Meiqing Yang, Yubo Liu, Jie Wang, Jiang Huang, Zheng Ren
Mitochondrial DNA analysis is widely used in determining its contribution to rare and common genetic diseases, identifying and interpreting acquired variants in cancer, ageing and age-related diseases, analysing variations in pedigree and population studies, and individual identification in forensic medicine (Brandon et al. 2009). The copy number of mtDNA in human cells is much higher than that of nuclear DNA. For this reason, mitochondrial DNA analysis can provide useful results for forensic samples that have failed to obtain a successful nuclear DNA profile (Bandelt et al. 2012). With the application of various molecular biological detection methods in forensic identification cases, mitochondrial DNA sequence analysis has been properly verified, and become a reliable procedure for testing biological evidence encountered in forensic criminal cases.
In vitro cytotoxicity of polyphenols from Datura innoxia aqueous leaf-extract on human leukemia K562 cells: DNA and nuclear proteins as targets
Published in Drug and Chemical Toxicology, 2020
Elham Chamani, Roshanak Ebrahimi, Khatereh Khorsandi, Azadeh Meshkini, Asghar Zarban, Gholamreza Sharifzadeh
Studies have shown that DNA is a pharmacological target of many of the drugs currently in clinical use or in advanced clinical trials (Hurley and Boyd 1988, Sirajuddin et al. 2013). In the eukaryotes, nuclear DNA interacts with histone proteins and forms a nucleoprotein complex known as chromatin. Chromatin arranges the nuclear genome into a restricted volume. The first level of chromatin organization consists of DNA-folding around histone proteins to shape the fundamental unit of the chromatin, the nucleosome (Hübner et al. 2013). In a nucleosome, 147 bp of DNA are enfolded in an octamer with two copies of four core histone proteins (H2A, H2B, H3, and H4) (Nair and Kumar 2012). As a linker histone, histone H1 surrounds the chromatosome by protecting the internucleosomal linker DNA near the nucleosome entry-exit point (Dixon et al. 2016, Kalashnikova et al. 2016).
The Moral Choices on CRISPR Babies
Published in The American Journal of Bioethics, 2019
In favor: healthy children. In cases where a woman’s eggs have a heritable genetic abnormality, as in mitochondrial mutations, a dominant allele associated with a disease, or both she and her husband have recessive genes linked to a disease, which could give rise to a genetically abnormal child, gene editing could in theory result in a healthy offspring. In such circumstances, where all of a woman’s eggs are defective, preimplantation genetic screening (PGS) is unlikely to resolve the problem. For parents who wish to have a healthy child with their nuclear DNA, gene editing may be the only choice. Considering the interests of the parents and the limited use of gene editing purely for therapeutic purposes, an argument can be made that it is the ethical thing to do once the procedure can be proven safe and effective. This argument is implicit in the plan by Russian scientists to use CRISPR on the embryos of deaf couples who do not want deaf children (Le Page 2019).