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Exonic
An exon is any part of a gene that will form a part of the final mature RNA produced by that gene after introns have been removed by RNA splicing. The term ''exon'' refers to both the DNA sequence within a gene and to the corresponding sequence in RNA transcripts. In RNA splicing, introns are removed and exons are covalently joined to one another as part of generating the mature RNA. Just as the entire set of genes for a species constitutes the genome, the entire set of exons constitutes the exome. History The term ''exon'' derives from the expressed region and was coined by American biochemist Walter Gilbert in 1978: "The notion of the cistron… must be replaced by that of a transcription unit containing regions which will be lost from the mature messengerwhich I suggest we call introns (for intragenic regions)alternating with regions which will be expressedexons." This definition was originally made for protein-coding transcripts that are spliced before being translated. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intron
An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word ''intron'' is derived from the term ''intragenic region'', i.e. a region inside a gene."The notion of the cistron .e., gene... must be replaced by that of a transcription unit containing regions which will be lost from the mature messenger – which I suggest we call introns (for intragenic regions) – alternating with regions which will be expressed – exons." (Gilbert 1978) The term ''intron'' refers to both the DNA sequence within a gene and the corresponding RNA sequence in RNA transcripts. The non-intron sequences that become joined by this RNA processing to form the mature RNA are called exons. Introns are found in the genes of most organisms and many viruses and they can be located in both protein-coding genes and genes that function as RNA (noncoding genes). There are four main types of introns: tRNA introns, group I introns, group II introns, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exome Sequencing
Exome sequencing, also known as whole exome sequencing (WES), is a genomic technique for sequencing all of the protein-coding regions of genes in a genome (known as the exome). It consists of two steps: the first step is to select only the subset of DNA that encodes proteins. These regions are known as exons—humans have about 180,000 exons, constituting about 1% of the human genome, or approximately 30 million base pairs. The second step is to sequence the exonic DNA using any high-throughput DNA sequencing technology. The goal of this approach is to identify genetic variants that alter protein sequences, and to do this at a much lower cost than whole-genome sequencing. Since these variants can be responsible for both Mendelian and common polygenic diseases, such as Alzheimer's disease, whole exome sequencing has been applied both in academic research and as a clinical diagnostic. Motivation and comparison to other approaches Exome sequencing is especially effective in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axon
An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands. In certain sensory neurons (pseudounipolar neurons), such as those for touch and warmth, the axons are called afferent nerve fibers and the electrical impulse travels along these from the periphery to the cell body and from the cell body to the spinal cord along another branch of the same axon. Axon dysfunction can be the cause of many inherited and acquired neurological disorders that affect both the peripheral and central neurons. Nerve fibers are classed into three typesgroup A nerve fibers, group B nerve fibers, and group C nerve fibers. Groups A and B are myelinated, and group C are unmyelinated. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligation (molecular Biology)
In molecular biology, ligation is the joining of two nucleic acid fragments through the action of an enzyme. It is an essential laboratory procedure in the molecular cloning of DNA, whereby DNA fragments are joined to create recombinant DNA molecules (such as when a foreign DNA fragment is inserted into a plasmid). The ends of DNA fragments are joined by the formation of phosphodiester bonds between the 3'-hydroxyl of one DNA terminus with the 5'-phosphoryl of another. RNA may also be ligated similarly. A co-factor is generally involved in the reaction, and this is usually ATP or NAD+. Ligation in the laboratory is normally performed using T4 DNA ligase. However, procedures for ligation without the use of standard DNA ligase are also popular. Ligation reaction The mechanism of the ligation reaction was first elucidated in the laboratory of I. Robert Lehman. Two fragments of DNA may be joined by DNA ligase which catalyzes the formation of a phosphodiester bond between the 3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-value
C-value is the amount, in picograms, of DNA contained within a haploid nucleus (e.g. a gamete) or one half the amount in a diploid somatic cell of a eukaryotic organism. In some cases (notably among diploid organisms), the terms C-value and genome size are used interchangeably; however, in polyploids the C-value may represent two or more genomes contained within the same nucleus. Greilhuber ''et al.'' have suggested some new layers of terminology and associated abbreviations to clarify this issue, but these somewhat complex additions are yet to be used by other authors. Origin of the term Many authors have incorrectly assumed that the 'C' in "C-value" refers to "characteristic", "content", or "complement". Even among authors who have attempted to trace the origin of the term, there had been some confusion because Hewson Swift did not define it explicitly when he coined it in 1950. In his original paper, Swift appeared to use the designation "1C value", "2C value", etc., in re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome Size
Genome size is the total amount of DNA contained within one copy of a single complete genome. It is typically measured in terms of mass in picograms (trillionths (10−12) of a gram, abbreviated pg) or less frequently in daltons, or as the total number of nucleotide base pairs, usually in megabases (millions of base pairs, abbreviated Mb or Mbp). One picogram is equal to 978 megabases. In diploid organisms, genome size is often used interchangeably with the term C-value. An organism's complexity is not directly proportional to its genome size; total DNA content is widely variable between biological taxa. Some single-celled organisms have much more DNA than humans, for reasons that remain unclear (see non-coding DNA and C-value enigma). Origin of the term The term "genome size" is often erroneously attributed to a 1976 paper by Ralph Hinegardner, even in discussions dealing specifically with terminology in this area of research (e.g., Greilhuber 2005). Notably, Hinegardner u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whole Genome Sequencing
Whole genome sequencing (WGS), also known as full genome sequencing, complete genome sequencing, or entire genome sequencing, is the process of determining the entirety, or nearly the entirety, of the DNA sequence of an organism's genome at a single time. This entails sequencing all of an organism's chromosomal DNA as well as DNA contained in the mitochondrial DNA, mitochondria and, for plants, in the chloroplast. Whole genome sequencing has largely been used as a research tool, but was being introduced to clinics in 2014. In the future of personalized medicine, whole genome sequence data may be an important tool to guide therapeutic intervention. The tool of DNA sequencing, gene sequencing at Single-nucleotide polymorphism, SNP level is also used to pinpoint functional variants from association studies and improve the knowledge available to researchers interested in evolutionary biology, and hence may lay the foundation for predicting disease susceptibility and drug response. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precision Medicine
Precision, precise or precisely may refer to: Science, and technology, and mathematics Mathematics and computing (general) * Accuracy and precision, measurement deviation from true value and its scatter * Significant figures, the number of digits that carry real information about a measurement * Precision and recall, in information retrieval: the proportion of relevant documents returned * Precision (computer science), a measure of the detail in which a quantity is expressed * Precision (statistics), a model parameter or a quantification of precision Computing products * Dell Precision, a line of Dell workstations * Precision Architecture, former name for PA-RISC, a reduced instruction set architecture developed by Hewlett-Packard * Ubuntu 12.04 "Precise Pangolin", Canonical's sixteenth release of Ubuntu Companies * Precision Air, an airline based in Tanzania * Precision Castparts Corp., a casting company based in Portland, Oregon, in the United States * Precision Drilling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Health Care
Health care or healthcare is the improvement of health via the prevention, diagnosis, treatment, amelioration or cure of disease, illness, injury, and other physical and mental impairments in people. Health care is delivered by health professionals and allied health fields. Medicine, dentistry, pharmacy, midwifery, nursing, optometry, audiology, psychology, occupational therapy, physical therapy, athletic training, and other health professions all constitute health care. It includes work done in providing primary care, secondary care, and tertiary care, as well as in public health. Access to health care may vary across countries, communities, and individuals, influenced by social and economic conditions as well as health policies. Providing health care services means "the timely use of personal health services to achieve the best possible health outcomes". Factors to consider in terms of health care access include financial limitations (such as insurance coverage), geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Omics
The branches of science known informally as omics are various disciplines in biology whose names end in the suffix '' -omics'', such as genomics, proteomics, metabolomics, metagenomics, phenomics and transcriptomics. Omics aims at the collective characterization and quantification of pools of biological molecules that translate into the structure, function, and dynamics of an organism or organisms . The related suffix -ome is used to address the objects of study of such fields, such as the genome, proteome or metabolome respectively. The suffix ''-ome'' as used in molecular biology refers to a ''totality'' of some sort; it is an example of a "neo-suffix" formed by abstraction from various Greek terms in , a sequence that does not form an identifiable suffix in Greek. Functional genomics aims at identifying the functions of as many genes as possible of a given organism. It combines different -omics techniques such as transcriptomics and proteomics with saturated mutant collec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intergenic Region
An intergenic region is a stretch of DNA sequences located between genes. Intergenic regions may contain functional elements and junk DNA. ''Inter''genic regions should not be confused with ''intra''genic regions (or introns), which are non-coding regions that are found ''within'' genes, especially within the genes of eukaryotic organisms. Properties and functions Intergenic regions may contain a number of functional DNA sequences such as promoters and regulatory elements, enhancers, spacers, and (in eukaryotes) centromeres. They may also contain origins of replication, scaffold attachment regions, and transposons and viruses. Non-functional DNA elements such as pseudogenes and repetitive DNA, both of which are types of junk DNA, can also be found in intergenic regions—although they may also be located within genes in introns. As all scientific knowledge is ultimately tentative—and in principle subject to revision given better evidence—it is possible s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Genome
The human genome is a complete set of nucleic acid sequences for humans, encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule found within individual mitochondria. These are usually treated separately as the nuclear genome and the mitochondrial genome. Human genomes include both protein-coding DNA sequences and various types of DNA that does not encode proteins. The latter is a diverse category that includes DNA coding for non-translated RNA, such as that for ribosomal RNA, transfer RNA, ribozymes, small nuclear RNAs, and several types of regulatory RNAs. It also includes promoters and their associated gene-regulatory elements, DNA playing structural and replicatory roles, such as scaffolding regions, telomeres, centromeres, and origins of replication, plus large numbers of transposable elements, inserted viral DNA, non-functional pseudogenes and simple, highly-repetitive sequences. Introns make up a large percentage of non-coding DNA. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
