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Chromosome Landing
Chromosomal landing is a genetic technique used to identify and isolate clones in a genetic library. Chromosomal landing reduces the problem of analyzing large, and/or highly repetitive genomes by minimizing the need for chromosome walking. It is based on the principle that the expected average between- marker distances can be smaller than the average insert length of a clone library containing the gene of interest. From the abstract of : :The strategy of chromosome walking is based on the assumption that it is difficult and time consuming to find DNA markers that are physically close to a gene of interest. Recent technological developments invalidate this assumption for many species. As a result, the mapping paradigm has now changed such that one first isolates one or more DNA marker(s) at a physical distance from the targeted gene that is less than the average insert size of the genomic library being used for clone isolation. The DNA marker is then used to screen the library and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Marker
A genetic marker is a gene or DNA sequence with a known location on a chromosome that can be used to identify individuals or species. It can be described as a variation (which may arise due to mutation or alteration in the genomic loci) that can be observed. A genetic marker may be a short DNA sequence, such as a sequence surrounding a single base-pair change ( single nucleotide polymorphism, SNP), or a long one, like minisatellites. Background For many years, gene mapping was limited to identifying organisms by traditional phenotypes markers. This included genes that encoded easily observable characteristics such as blood types or seed shapes. The insufficient number of these types of characteristics in several organisms limited the mapping efforts that could be done. This prompted the development of gene markers which could identify genetic characteristics that are not readily observable in organisms (such as protein variation). Types Some commonly used types of genetic markers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Distance
Genetic distance is a measure of the genetic divergence between species or between populations within a species, whether the distance measures time from common ancestor or degree of differentiation. Populations with many similar alleles have small genetic distances. This indicates that they are closely related and have a recent common ancestor. Genetic distance is useful for reconstructing the history of populations, such as the multiple human expansions out of Africa. It is also used for understanding the origin of biodiversity. For example, the genetic distances between different breeds of domesticated animals are often investigated in order to determine which breeds should be protected to maintain genetic diversity. Biological foundation In the genome of an organism, each gene is located at a specific place called the locus for that gene. Allelic variations at these loci cause phenotypic variation within species (e.g. hair colour, eye colour). However, most alleles do not hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome Walking
Primer walking is a technique used to clone a gene (e.g., disease gene) from its known closest markers (e.g., known gene). As a result, it is employed in cloning and sequencing efforts in plants, fungi, and mammals with minor alterations. This technique, also known as "directed sequencing," employs a series of Sanger sequencing reactions to either confirm the reference sequence of a known plasmid or PCR product based on the reference sequence (sequence confirmation service) or to discover the unknown sequence of a full plasmid or PCR product by designing primers to sequence overlapping sections (sequence discovery service). Primer walking: a DNA sequencing method Primer walking is a method to determine the sequence of DNA up to the 1.3–7.0 kb range whereas chromosome walking is used to produce the clones of already known sequences of the gene. Too long fragments cannot be sequenced in a single sequence read using the chain termination method. This method works by dividing th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Screen
A genetic screen or mutagenesis screen is an experimental technique used to identify and select individuals who possess a phenotype of interest in a mutagenized population. Hence a genetic screen is a type of phenotypic screen. Genetic screens can provide important information on gene function as well as the molecular events that underlie a biological process or pathway. While genome projects have identified an extensive inventory of genes in many different organisms, genetic screens can provide valuable insight as to how those genes function. Basic screening Forward genetics (or a forward genetic screen) starts with a phenotype and then attempts to identify the causative mutation and thus gene(s) responsible for the phenotype. For instance, the famous screen by Christiane Nüsslein-Volhard and Eric Wieschaus mutagenized fruit flies and then set out to find the genes causing the observed mutant phenotypes. Successful forward genetic screens often require a defined genetic ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Map-based Cloning
A genetic screen or mutagenesis screen is an experimental technique used to identify and select individuals who possess a phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological pr ... of interest in a mutagenized population. Hence a genetic screen is a type of phenotypic screen. Genetic screens can provide important information on gene function as well as the molecular events that underlie a biological process or pathway. While genome projects have identified an extensive inventory of genes in many different organisms, genetic screens can provide valuable insight as to how those genes function. Basic screening Forward genetics (or a forward genetic screen) starts with a phenotype and then attempts to identify the causative mutation and thus gene(s) responsible for the phenotype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantitative Traits
Quantitative may refer to: * Quantitative research, scientific investigation of quantitative properties * Quantitative analysis (other) * Quantitative verse, a metrical system in poetry * Statistics, also known as quantitative analysis * Numerical data, also known as quantitative data * Quantification (science) In mathematics and empirical science, quantification (or quantitation) is the act of counting and measuring that maps human sense observations and experiences into quantities. Quantification in this sense is fundamental to the scientific method ... See also * Qualitative {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes (the archaea and bacteria). By one definition, plants form the clade Viridiplantae (Latin name for "green plants") which is sister of the Glaucophyta, and consists of the green algae and Embryophyta (land plants). The latter includes the flowering plants, conifers and other gymnosperms, ferns and their allies, hornworts, liverworts, and mosses. Most plants are multicellular organisms. Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria. Their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic or mycotrophic and have lost the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primer Walking
Primer walking is a technique used to clone a gene (e.g., disease gene) from its known closest markers (e.g., known gene). As a result, it is employed in cloning and sequencing efforts in plants, fungi, and mammals with minor alterations. This technique, also known as "directed sequencing," employs a series of Sanger sequencing reactions to either confirm the reference sequence of a known plasmid or PCR product based on the reference sequence (sequence confirmation service) or to discover the unknown sequence of a full plasmid or PCR product by designing primers to sequence overlapping sections (sequence discovery service). Primer walking: a DNA sequencing method Primer walking is a method to determine the sequence of DNA up to the 1.3–7.0 kb range whereas chromosome walking is used to produce the clones of already known sequences of the gene. Too long fragments cannot be sequenced in a single sequence read using the chain termination method. This method works by dividing the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physical structure of biological macromolecules is known as molecular biology. Molecular biology was first described as an approach focused on the underpinnings of biological phenomena - uncovering the structures of biological molecules as well as their interactions, and how these interactions explain observations of classical biology. In 1945 the term molecular biology was used by physicist William Astbury. In 1953 Francis Crick, James Watson, Rosalind Franklin, and colleagues, working at Medical Research Council unit, Cavendish laboratory, Cambridge (now the MRC Laboratory of Molecular Biology), made a double helix model of DNA which changed the entire research scenario. They proposed the DNA structure based on previous research done by Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
