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Forward Genetics
Forward genetics is a molecular genetics approach of determining the genetic basis responsible for a phenotype. Forward genetics provides an unbiased approach because it relies heavily on identifying the genes or genetic factors that cause a particular phenotype or trait of interest. This was initially done by using naturally occurring mutations or inducing mutants with radiation, chemicals, or insertional mutagenesis (e.g. transposable elements). Subsequent breeding takes place, mutant individuals are isolated, and then the gene is mapped. Forward genetics can be thought of as a counter to reverse genetics, which determines the function of a gene by analyzing the phenotypic effects of altered DNA sequences. Mutant phenotypes are often observed long before having any idea which gene is responsible, which can lead to genes being named after their mutant phenotype (e.g. Drosophila ''rosy'' gene which is named after the eye colour in mutants). Techniques used in Forward Genetics Fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Genetics
Molecular genetics is a sub-field of biology that addresses how differences in the structures or expression of DNA molecules manifests as variation among organisms. Molecular genetics often applies an "investigative approach" to determine the structure and/or function of genes in an organism's genome using genetic screens. The field of study is based on the merging of several sub-fields in biology: classical Mendelian inheritance, Cell biology, cellular biology, molecular biology, biochemistry, and biotechnology. Researchers search for mutations in a gene or induce mutations in a gene to link a gene sequence to a specific phenotype. Molecular genetics is a powerful methodology for linking mutations to genetic conditions that may aid the search for treatments/cures for various genetics diseases. History For molecular genetics to develop as a discipline, several scientific discoveries were necessary. The discovery of DNA as a means to transfer the genetic code of life f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forward Genetics Steps
Forward is a relative direction In geometry, a position or position vector, also known as location vector or radius vector, is a Euclidean vector that represents the position of a point ''P'' in space in relation to an arbitrary reference origin ''O''. Usually denoted x, r, or ..., the opposite of backward. Forward may also refer to: People * Forward (surname) Sports * Forward (association football) * Forward (basketball), including: ** Point forward ** Power forward (basketball) ** Small forward * Forward (ice hockey) ** Power forward (ice hockey) * In rugby football: ** Forwards (rugby league), in rugby league football ** Forwards (rugby union), in rugby union football * Forward Sports, a Pakistan sportswear brand * BK Forward, a Swedish club for association football and bandy Politics * Avante (political party) (Portuguese for ''forward''), a political party in Brazil * Forward (Belgium), a political party in Belgium * Forward (Denmark), a political party in Denmark * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Genome Project
The Human Genome Project (HGP) was an international scientific research project with the goal of determining the base pairs that make up human DNA, and of identifying, mapping and sequencing all of the genes of the human genome from both a physical and a functional standpoint. It started in 1990 and was completed in 2003. It remains the world's largest collaborative biological project. Planning started after the idea was picked up in 1984 by the US government, the project formally launched in 1990, and was declared essentially complete on April 14, 2003, but included only about 85% of the genome. Level "complete genome" was achieved in May 2021, with a remaining only 0.3% bases covered by potential issues. The final gapless assembly was finished in January 2022. Funding came from the United States government through the National Institutes of Health (NIH) as well as numerous other groups from around the world. A parallel project was conducted outside the government by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Hunt Morgan
Thomas Hunt Morgan (September 25, 1866 – December 4, 1945) was an American evolutionary biologist, geneticist, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries elucidating the role that the chromosome plays in heredity. Morgan received his Ph.D. from Johns Hopkins University in zoology in 1890 and researched embryology during his tenure at Bryn Mawr. Following the rediscovery of Mendelian inheritance in 1900, Morgan began to study the genetic characteristics of the fruit fly ''Drosophila melanogaster''. In his famous Fly Room at Columbia University's Schermerhorn Hall, Morgan demonstrated that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. During his distinguished career, Morgan wrote 22 books and 370 scientific papers. As a result of his work, ''Drosophila'' became a major model organism in contemporary genetics. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossbreeding
A crossbreed is an organism with purebred parents of two different breeds, varieties, or populations. ''Crossbreeding'', sometimes called "designer crossbreeding", is the process of breeding such an organism, While crossbreeding is used to maintain health and viability of organisms, irresponsible crossbreeding can also produce organisms of inferior quality or dilute a purebred gene pool to the point of extinction of a given breed of organism. A domestic animal of unknown ancestry, where the breed status of only one parent or grandparent is known, may also be called a crossbreed though the term "mixed breed" is technically more accurate. Outcrossing is a type of crossbreeding used within a purebred breed to increase the genetic diversity within the breed, particularly when there is a need to avoid inbreeding. In animal breeding, ''crossbreeds'' are crosses within a single species, while '' hybrids'' are crosses between different species. In plant breeding terminology, the term ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical Genetics
Classical genetics is the branch of genetics based solely on visible results of reproductive acts. It is the oldest discipline in the field of genetics, going back to the experiments on Mendelian inheritance by Gregor Mendel who made it possible to identify the basic mechanisms of heredity. Subsequently, these mechanisms have been studied and explained at the molecular level. Classical genetics consists of the techniques and methodologies of genetics that were in use before the advent of molecular biology. A key discovery of classical genetics in eukaryotes was genetic linkage. The observation that some genes do not segregate independently at meiosis broke the laws of Mendelian inheritance and provided science with a way to map characteristics to a location on the chromosomes. Linkage maps are still used today, especially in breeding for plant improvement. After the discovery of the genetic code and such tools of cloning as restriction enzymes, the avenues of investigation open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome Jumping
Chromosome jumping is a tool of molecular biology that is used in the physical mapping of genomes. It is related to several other tools used for the same purpose, including chromosome walking. Chromosome jumping is used to bypass regions difficult to clone, such as those containing repetitive DNA, that cannot be easily mapped by chromosome walking, and is useful in moving along a chromosome rapidly in search of a particular gene. Unlike chromosome walking, chromosome jumping is able to start on one point of the chromosome in order to traverse potential distant point of the same chromosome without cloning the intervening sequences. The ends of a large DNA fragment is the target cloning section of the chromosome jumping while the middle section gets removed by sequences of chemical manipulations prior to the cloning step. Process Chromosome jumping enables two ends of a DNA sequence to be cloned without the middle section. Genomic DNA may be partially digested using restriction ... [...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] |
Cystic Fibrosis
Cystic fibrosis (CF) is a rare genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. Long-term issues include difficulty breathing and coughing up mucus as a result of frequent lung infections. Other signs and symptoms may include sinus infections, poor growth, fatty stool, clubbing of the fingers and toes, and infertility in most males. Different people may have different degrees of symptoms. Cystic fibrosis is inherited in an autosomal recessive manner. It is caused by the presence of mutations in both copies of the gene for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Those with a single working copy are carriers and otherwise mostly healthy. CFTR is involved in the production of sweat, digestive fluids, and mucus. When the CFTR is not functional, secretions which are usually thin instead become thick. The condition is diagnosed by a sweat test and genetic testing. Screening of infants at bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Association Studies
Genetic association is when one or more genotypes within a population co-occur with a phenotypic trait more often than would be expected by chance occurrence. Studies of genetic association aim to test whether single-locus alleles or genotype frequencies (or more generally, multilocus haplotype frequencies) differ between two groups of individuals (usually diseased subjects and healthy controls). Genetic association studies today are based on the principle that genotypes can be compared "directly", i.e. with the sequences of the actual genomes or exomes via whole genome sequencing or whole exome sequencing. Before 2010, DNA sequencing methods were used. Description Genetic association can be between phenotypes, such as visible characteristics such as flower color or height, between a phenotype and a genetic polymorphism, such as a single nucleotide polymorphism (SNP), or between two genetic polymorphisms. Association between genetic polymorphisms occurs when there is non-ran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Positional Cloning
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 F. Wieschaus, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-nucleotide Polymorphism
In genetics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently large fraction of the population (e.g. 1% or more), many publications do not apply such a frequency threshold. For example, at a specific base position in the human genome, the G nucleotide may appear in most individuals, but in a minority of individuals, the position is occupied by an A. This means that there is a SNP at this specific position, and the two possible nucleotide variations – G or A – are said to be the alleles for this specific position. SNPs pinpoint differences in our susceptibility to a wide range of diseases, for example age-related macular degeneration (a common SNP in the CFH gene is associated with increased risk of the disease) or nonalcoholic fatty liver disease (a SNP in the PNPLA3 gene is associated with inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
