Food Interactions, Sirtuins, Genes, Homeostasis, and General Discussion
Chuong Pham-Huy, Bruno Pham Huy in Food and Lifestyle in Health and Disease, 2022
The key difference between RNA and DNA structures is that the ribose sugar in RNA has a hydroxyl (-OH) group which is absent in DNA, and the thymine base of DNA is replaced by the uracil base in RNA (107, 111–113). The nucleotides that comprise DNA include adenine (A), guanine (G), cytosine (C), and thymine (T); whereas RNA nucleotides include A, G, C, and uracil (U). Moreover, RNA has only one long strand or chain in almost species, except in some viruses, while DNA has a double strand and looks like a twisted ladder in all species from bacteria and plants to invertebrates and humans (107, 111–113). DNA is defined as a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms. The main role of RNA is to transfer the genetic code needed for the creation of proteins from the nucleus to the ribosome (111). This process prevents the DNA from having to leave the nucleus. This keeps the DNA and genetic code protected from damage. Without RNA, proteins could never be made. RNA molecules are not only involved in protein synthesis, but also sometimes in the transmission of genetic information (111).
Identification of the living and the dead
Jason Payne-James, Richard Jones in Simpson's Forensic Medicine, 2019
The molecule of DNA has two strands of sugar and phosphate molecules that are linked by combinations of four bases, adenine, thymine, cytosine and guanine, forming a double helix structure. Only about 10 per cent of the molecule is used for genetic coding (the active genes), the remainder being ‘silent’. In these silent zones, there are between 200 and 14,000 repeats of identical sequences of the four bases. Sir Alec Jeffreys found that adjacent sequences were constant for a given individual and that they were transmitted, like blood groups, from the DNA of each parent. The statistical analysis of DNA identification is extremely complex and it is important that any calculations are based upon the DNA characteristics of a relevant population and not upon the characteristics of a ‘standard’ population somewhere else in the world. Forensic genetics developed from protein-based techniques and brought with it the term ‘DNA fingerprinting’, this being based on restriction fragment length polymorphisms (RFLPs) of high-molecular-weight DNA. Development of analytical techniques resulted such as the amplification of much smaller short tandem repeat (STR) sequences using the polymerase chain reaction (PCR) which soon replaced RFLP analysis and became standard in genetic identification. STR multiplexes are now available which simultaneously amplify up to 30 STR loci from as little as 15 cells or fewer. The huge volume of information associated with the great range of observed STR genotypes allows for genetic individualisation (with the exception of identical twins).
Case Investigation
Kevin L. Erskine, Erica J. Armstrong in Water-Related Death Investigation, 2021
Investigation into the cause of death for any unidentified individual cannot begin until the identity of the victim is known. In the past, estimations and a lot of luck were needed to identify skeletal or badly decomposed remains. Yet today, modern technology has made it much simpler. The new technology, called Parabon Snapshot, allows an investigator to obtain a photographic image of the deceased by using a sample of the victim’s DNA. DNA carries genetics, which determines a person’s physical characteristics, producing a wide variety of physical appearances from one person to the next. Snapshot reads these variances and predicts what a person looked like. This process is simply amazing, and the likeness of the person antemortem (before death) is spot on. Using SNP (Single-Nucleotide Polymorphism) technology, Snapshot generates a composite sketch (the process is called DNA phenotyping). These composites include sex, freckling, skin, hair and eye color, ancestry and face morphology. Composites reportedly have greater than 90% accuracy.
Patenting Foundational Technologies: Lessons From CRISPR and Other Core Biotechnologies
Published in The American Journal of Bioethics, 2018
Oliver Feeney, Julian Cockbain, Michael Morrison, Lisa Diependaele, Kristof Van Assche, Sigrid Sterckx
DNA is made up of paired strands of bases (nucleic acids denoted by the letters C, A, G, and T), where each base pairs with one other, T binding to A, and G to C, linking the two strands in the famous double helix structure. If natural DNA is chopped up with nucleases, and if short DNA sequences (primers) are added to the mixture, then one has a mixture containing cut fragments bound to the added primers. Adding nucleic acids and an enzyme (DNA polymerase), which causes the ragged ends of these bound fragments to be extended with the appropriate nucleic acids to become blunt-ended, yields a mixture of short, paired DNA molecules. Repeatedly separating and regrowing the paired sections yields multiple copies of the short paired molecules: Starting with one combination of GGAGCTTAG bound to its complementary sequence CCTCGAATC yields two versions of each in the first replication, four in the second, and so on. The increase of copies is exponential and, by analogy with nuclear fission in a reactor or bomb, is called a chain reaction—the “polymerase chain reaction” or PCR. In this way, enough copies of the short paired molecules can be produced relatively cheaply and quickly to enable detection and characterization.
Chromosome aberration in typical biological systems under exposure to low- and high-intensity magnetic fields
Published in Electromagnetic Biology and Medicine, 2020
Emanuele Calabrò, Hit Kishore Goswami, Salvatore Magazù
Chromosomes are molecules composed of the deoxyribonucleic acid (DNA) that represents the genetic material of a living being. In human beings, there are 22 pairs of chromosomes and 2 sex chromosomes for a total of 46. DNA is an organic polymer composed of monomers that are called nucleotides. They consist of a phosphate group and a nitrogenous base linked to deoxyribose by the so-called N-glycoside bond. The nitrogenous bases that can be used in nucleotide formation are adenine, cytosine, guanine and thymine disposed in base pairs of adenine-thymine (A-T) and guanine-cytosine (G-C) that in aqueous solutions are linked one each other by hydrogen bonds forming a double helix structure because of the repulsions between the negative charge of phosphate groups. This double helix structure is bound to proteins (the histones) that have positively charged amino acids in order to bind the DNA which is negatively charged and is wrapped around the core of histone of eight protein subunits forming the nucleosome. About 200 base pairs of DNA are coiled around each histone. This coil is untwisted generating a negative superturn per nucleosome that is the active chromatin.
Association between NOS3 polymorphisms and osteonecrosis of the femoral head
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Xiaodong Zhao, Fuqiang Yang, Luwei Sun, Ali Zhang
Until now, the replacement of artificial hip joint represents an effective way to relieve pain and improve joint functions among ONFH cases. However, artificial joint costs highly, with limited service life time [23]. ONFH has brought about serious torment and heavy financial burden to the patients. Therefore, early diagnosis and prevention are critical ways for the settlement of ONFH. However, due to unclear etiology, it is difficult to realize such operations in clinic. As we all know, not all of the individuals exposing to risk factors would eventually subject to ONFH. This phenomenon is determined by individual susceptibility which is closely related to genetic information. DNA is the basic carrier of human genetic information whose characteristics cannot be changed along with either time or space. Gene polymorphism is an important reason for differences in individual susceptibility to diseases, and single nucleotide polymorphism (SNP) stands for a most common form [24–28].
Related Knowledge Centers
- Nucleic Acid
- Polymer
- Polynucleotide
- Protein
- Rna
- Virus
- Lipid
- Nucleic Acid Double Helix
- Genetics
- Reproduction