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Cancer Biology and Genetics for Non-Biologists
Published in Trevor F. Cox, Medical Statistics for Cancer Studies, 2022
Genes are particular areas of the DNA where the coding allows for protein production or some RNA function (see later). Humans have about 20,000 genes located on the chromosomes, each containing between a few thousand to over 2 million base pairs, with an average length of 27,000, and if you do the calculation, that is only about of the total DNA. The gene regions of the DNA are said to be coding regions and the rest non-coding regions. Particular genes are referred to by name and their position (locus) on the chromosome where they reside, for example KRAS is a gene on the short arm of chromosome 12, position 12.1. KRAS has a lot to do with cancer.
The Genetic Risk of a Couple Aiming to Conceive
Published in Carlos Simón, Carmen Rubio, Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
Joe Leigh Simpson, Svetlana Rechitsky, Anver Kuliev
The protein-coding regions are defined as exons, and code for 21,000 genes in the human genome. This constitutes 1.5% of the genome. At least 5,000 Mendelian disorders are exonic in origin (1) The other 98.5% of the genome contains non-coding DNA, believed to be responsible for gene regulation. Non-coding regions (introns) may separate coding genes or be interspersed among exons of a clinically significant gene. At a single genetic locus, many different nuclear mutations may arise. In compound heterozygosity, two different alleles may show different base mutations, each deleterious. Causative mutant alleles influencing a single phenotype may exist in two different genetic loci (mixed heterozygosity). It follows that both genes are necessary for a normal phenotype.
Human Responses to Endotoxin: Role of the Genetic Background
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
The TNF locus consists of three functional genes. TNF is positioned between lymphotoxin α (LTα) in the upstream direction and lymphotoxin β (LTβ) in the downstream direction (Fig. 1). Genomic polymorphisms within in the TNF locus have been under intense investigation. Genetic variation within the TNF locus is rare as the TNF gene is well conserved throughout evolution (10). The coding region, in particular, is highly conserved.
Heterozygous missense mutation of the RELN gene is one of the causes of epilepsy
Published in Neurological Research, 2022
Xi-Qin Fang, Ran-Ran Zhang, Xue-Wu Liu
The proband’s diagnosis was based on the clinical manifestations and examinations (including magnetic resonance imaging and electroencephalography). Mutations were determined using target sequence capture combined with high-throughput sequencing technology. This method can detect more than 95% of the exon area, and the coverage rate of the target area can reach 99.8%. After obtaining peripheral blood samples from the three family members (proband, his mother, his grandmother), the samples were sent to the Jinzhun Medical Laboratory (Beijing, China). First, the DNA was interrupted to prepare a library, and then the DNA in the coding region of the target gene and the adjacent cutting region was captured and enriched by the chip. A high-throughput platform was used for mutation detection.
Novel Deleterious Mutation in Steroid-5α-Reductase-2 in 46, XY Disorders of Sex Development: Case Report Study
Published in Fetal and Pediatric Pathology, 2022
Mahboobeh Rafigh, Arash Salmaninejad, Behzad Sorouri Khorashad, Azadeh Arabi, Saman Milanizadeh, Mehran Hiradfar, Mohammad reza Abbaszadegan
Genomic DNA of the participants were extracted following standard salting out protocols from 5 ml of peripheral blood collected in EDTA tubes. Determined coding regions were amplified by polymerase chain reaction (PCR) using specific primers (Table 1). The PCR reaction was performed in a total volume of 25 ul, containing PCR buffer (+MgCl2) 1.5 ul, deoxyribonucleotide triphosphates (dNTPs) (10 mM) 0.5 ul, each primer (10 pmol/ul) 0.5 ul, 1 ul to 2 ul of genomic DNA, 0.2 ul of Taq DNA polymerase and 18.3 ul H2O. The PCR program was; denaturation at 95°C for 5 min, followed by 35 cycles of denaturation, annealing and elongation, respectively at 95 ̊C for 30 seconds, 60 ̊C for 30 seconds and 72 ̊C for 30 seconds, with a final elongation at 72 C for 5 min. The quality of PCR products were assessed upon running the samples in 2% agarose gel electrophoresis. Then the PCR products were sequenced by automated DNA sequencing via Applied Biosystems 3730 DNA Analyzer (Macrogen, Seoul, Korea). Mutation detection was carried out by sequence alignment (gene code) sequencer software.
Identification of a Novel β-Thalassemia Mutation at Codon 130 (+T) (HBB: c.391insT) in Han Chinese
Published in Hemoglobin, 2021
Wen-Juan Wang, Zi-Xuan Ding, Hui-Min Zhang, Ting-Ting Tao, Su-Ning Chen, Ling Xi
β-Thalassemia (β-thal) is an inherited blood disorder caused by genetic mutations of the β-globin gene (HBB). These mutations lead to a reduction [β+-thalassemia (β+-thal)] or the complete absence [β0-thalassemia (β0-thal)] of β-globin chain expression. Three main forms of β-thal have been described: β-thal major (β-TM), β-thal intermedia (β-TI) and β-thal minor. Individuals with β-TM inherit two mutated β-globin genes and present with severe anemia, requiring regular red blood cell (RBC) transfusions. More than 900 different mutations on the β-globin gene have so far been identified [1]. Most of the mutations are caused by point mutations, small deletions or insertions within the coding regions and the exon-intron junctions. There are about 50 mutations that have been found in China, including two mutations reported by our group. Although most of these occurred in Southern China [1–5], rare β-thal carriers can also be found in Northeastern and Western China. Here, we describe a novel mutation due to a nucleotide insertion in exon 3 of the β-globin gene.