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Topic: Complementation (genetics)

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In the News (Mon 27 May 19)

During the complementation test, if a phenotype is observed when a recessive mutation is combined in trans with another recessive mutation that has been mapped to the same area, it is concluded that these mutations are alleles of the same gene; neither allele produces a product that can restore wild-type function (Figure 1).
It was demonstrated that unc-13(n2813) did not complement a null or hypomorphic allele of unc-64, although a null allele of unc-13 fully complemented the unc-64 null allele.
The complementation test is a simple and fundamental assay in genetics used to assign a mutation to a gene.
www.wormbook.org /chapters/www_complementation/complementation.html   (6820 words)

An inverse genetics application is "cloning by complementation", but this will have many of the same concerns as standard complementation with the added concern of copy effects if multi-copy plasmids are used.
This question is largely a semantic one, but in general, unless intragenic complementation is fairly common, the few exceptional complementing pairs would not be said to define separate complementation groups.
Since complementation analysis treats only those functions necessaryto generate the required phenotype, it does not allow the detection of complementation groups unless their products are required for the phenotype in question.
lecturer.ukdw.ac.id /dhira/BactGenetics/complementation.html   (2001 words)

 LAB - Yeast Complementation Analysis
In conducting complementation analysis on randomly generated auxotrophs, one must be able to confirm the success of mating in order to interpret any lack of growth, or lack of complementation, among diploids formed from haploids of unknown genotype.
As a positive control for the formation of diploid cells during complementation analysis of the histidine metabolic pathway, random mutants must be generated in haploid strains that are known auxotrophs for another metabolite, in our case adenine.
It is for this reason that any mutagenesis and complementation analysis project must begin with haploid yeast strains of known mating type and of known genotype for the adenine marker alleles.
www.rickhershberger.com /bioactivesite/genetics/lab/yeast/complementation.htm   (4985 words)

 Molecular Genetics
Parasexual genetics can also be used to construct double and triple-knockout strains.
To verify that the recovered DNA sequence is responsible for the phenotype, the rescued plasmid is used to recreate the genotype by homologous recombination.
The method has been demonstrated using a genomic library to complement null mutants in several previously identified genes, but this was an isolated success until recently.
dictybase.org /tutorial/MolecularGenetics.htm   (738 words)

An inverse genetics application is "cloning by complementation", but this will have many of the same concerns as standard complementation with the added concern of copy effects if multi-copy plasmids are used.
This would suggest that the results of complementation analysis would be to define the number of genes in the region.
Since complementation analysis treats only those functions necessaryto generate the required phenotype, it does not allow the detection of complementation groups unless their products are required for the phenotype in question.
www.bact.wisc.edu /Bact370/complementation.html   (1998 words)

  Molecular genetics Encyclopedia   (Site not responding. Last check: )
Molecular genetics is the field of biology which studies the structure and function of genes at a molecular level.
It is so-called to differentiate it from other sub fields of genetics such as ecological genetics and population genetics.
An important area within molecular genetics is the use of molecular information to determine the patterns of descent, and therefore the correct scientific classification of organisms: this is called molecular systematics.
www.hallencyclopedia.com /topic/Molecular_genetics.html   (361 words)

  Complementation (genetics) Summary
A genetic complementation test is used to determine the location and nature of mutations.
Complementation tests allow molecular biologists and geneticists to specifically determine whether a mutation is in the same gene or in the same bacterial cistron as a known (i.e., test) mutation.
A complementation test (sometimes called a "cis-trans" test) is used in genetics to decide if two recessive mutant phenotypes are determined by mutations in the same gene or two different genes.
www.bookrags.com /Complementation_(genetics)   (638 words)

 MCDB 2150, Lecture 19
The critical requirement is that the two mutations must not destroy precisely the same genetic function and that when combined in a diploid or diploid-like situation, each of the damaged genomes must be able to compensate for the losses suffered by the other.
In addition, the extent of recombination must be substantially less than the level of complementation that is observed so that it will be clear that the restoration of function occurred because the two mutations destroyed two different units of function, and not because recombination created a normal gene and a doubly-defective gene.
Complementation in diploid organisms: As discussed above, use of the term "complementation" is usually reserved for cases in which the two mutations whose interactions are being studied have a similar phenotypic effect.
www.colorado.edu /MCDB/MCDB2150Fall/notes/L19.html   (2007 words)

 Viral Genetics | World of Genetics
Viral genetics, the study of the genetic mechanisms that operate during the life cycle of viruses, utilizes biophysical, biological, and genetic analyses to study the viral genome and its variation.
Virus genetics is studied by either investigating genome mutations or exchange of genetic material during the life cycle of the virus.
The frequency and types of genetic variations in the virus are influenced by the nature of the viral genome and its structure.
www.bookrags.com /research/viral-genetics-wog   (1387 words)

 Forward genetics in mammaliancells: functional approaches to gene discovery -- Stark and Gudkov 8 (10): 1925 -- Human ...
Genetic information from knockout mice is now available concerning the roles of signaling components identified in this way (for a recent example see ref. 31).
Often, knowledge of the genetic mechanism responsible for a particular gain of function or lesion has been obtained by using the techniques of classical genetics, involving either gene mapping by linkage analysis and subsequent positional cloning or the cloning and characterization of genomic regions involved in disease-related chromosomal rearrangements.
The genetic event underlying a particular phenotypic alteration can be identified relatively easily for dominant or co-dominant genes, which can be effectively identified and studied using many different techniques for transfer and isolation of amplified or overexpressed DNA (42-46).
hmg.oxfordjournals.org /cgi/content/full/8/10/1925   (11584 words)

 Genetics Glossary Co-Cz   (Site not responding. Last check: )
The union of two bacterial cells, during which chromosomal material is transferred from the donor to the recipient cell.
A term used by maize geneticists to indicate a mobile genetic element capable of producing an unstable mutant target gene; two types exist, the regulator and the receptor elements.
The cytological approach to genetics, mainly involving microscopic studies of chromosomes.
helios.bto.ed.ac.uk /bto/glossary/c2.htm   (1683 words)

Complementation by itself is ambiguous since this term can also refer to genes at different loci that complement to produce a different phenotype.
The only major difference between the two cases presented is that in the first case two different proteins are complementing as individual units to bring about a biochemical process where as in the second case two different proteins are complementing as a single bonded unit to bring about a biochemical process.
The fact that intragenic complementation does not occur for these genes would strongly suggest that the protein produced by each have damage to the same functional domain.
www.cabinsoftware.biz /Genetics_Tutorial/Part11.htm   (1485 words)

 Complementation   (Site not responding. Last check: )
In this application, complementation was used to relate a marker, LEU2, from the genetic map to a position on the molecular map (positive clone from ordered library or a restriction fragment on the restriction map).
Complementation should be very useful in testing a cloned DNA to see whether it contains the gene it is thought to contain.
Another way of connecting points on a genetic map with points on a molecular map is hybridization of genetic molecular markers to ordered contigs.
opbs.okstate.edu /~melcher/MG/MGW1/MG1232.html   (316 words)

 12 Interaction of Genes
As expected, intragenic complementation of this type is often observed with missense mutations, not with deletions, and only with special subsets of nonsense mutations.
Intragenic complementation of genes encoding multimeric proteins is surprisingly frequent among missense mutations of certain genes.
For example, 5 out of 10 genes controlling histidine biosynthesis show extensive complementation, and the nature of the genetic complementation maps suggest that multimeric proteins may be involved.
dbb.urmc.rochester.edu /labs/sherman_f/yeast/12.html   (2128 words)

 Virus Genetics   (Site not responding. Last check: )
This document and the accompanying lectures provide a summary of genetic mechanisms which operate in viruses and some of the practical implications which arise from these.
Biological analysis of the structure-function relationships of intact virus genomes and individual genetic elements usually involving analysis of the virus phenotype in vivo.
Conventional genetic analysis of animal viruses is based on the isolation and analysis of mutants, using plaque-purification techniques.
www.tulane.edu /~dmsander/WWW/224/Genetics.html   (196 words)

 Mendelian Genetics
Genetic Markers: Characteristic loci located at the same place on a pair of homologous chromosomes that allows us to distinguish one homologue from the other.  They are usually DNA sequence polymorphisms that can be detected by PCR.
In clinical settings genetic heterogeneity refers to the presence of a variety of genetic defects which cause the same disease, often due to mutations at different loci on the same gene, a finding common to many human diseases including Alzheimer's disease, cystic fibrosis, lipoprotein lipase and polycystic kidney disease.
Since complementation analysis treats only those functions necessary to generate the required phenotype, it does not allow the detection of complementation groups unless their products are required for the phenotype in question.
obiweb.bcgsc.ca /medgen/medgen520/Block4.htm   (7882 words)

 XPS Research & Discovery
Individuals in different complementation groups tend to have different degrees of deficiency in UV sensitivity and in UDS, so that it is possible usually to make an educated guess about what gene is affected if the first two tests have been done, realizing that this is only a guess and not reliable.
In my laboratory, the preferred method is DNA microinjection, in which the nucleus of a cell is injected with the normal version of an XP gene to see if the gene increases UDS, in which case the gene is proved to be same gene as is affected in the patient.
Knowing the complementation group will become very important in the future when gene therapy becomes available, since it will indicate what gene needs to be administered in the therapy.
www.xps.org /research_discovery.htm   (2467 words)

 Yeast Genetics Lecture
The degree of your temptation to call the two complementable mutations two genes is directly proportional to your subscription to the one gene, one enzyme hypothesis.
Strictly, then, complementation allows one to conclude that two mutations are either in different genes (like leu1 and leu2) or are functionally different alleles of the same gene (such as cmd1-1 and cmd1-2).
Classically, genetics starts with a mutant phenotype and asks questions such as what sort of gene (defect) might be responsible for color blindness or what sort of gene might be responsible for arrest in response to radiation.
www.dartmouth.edu /~brenner/102yeast.html   (2683 words)

 Advanced Genetics
She successfully isolated shrunken seed from a cross of a stock containing the functional, Sh4 allele in homozygous condition and an active Robertson Mu element with a stock containing a recessive sh4 allele in homozygous condition.
Interallelic or intracistronic complementation are rare events in that it is rare to find two alleles that exhibit it.
Genetic characterization showed that there was only one class of recombinant outside markers in these rare wildtype progeny.
www.hos.ufl.edu /lchweb/adghomework.html   (6267 words)

 February 07: Microbial genetics: DNA transfer, gene mapping.
Complementation allows one to identify the gene whose mutagenesis resulted in a physiological deficiency.
The approach is to reintroduce a "correct" copy of the gene into the mutant cells and demonstrate restored performance by "complementing" the defective copy of the gene.
NOTE - Complementation and recombination are invariably followed by a selection or a screen to identify the cells that have acquired the desired genes.
www.biosci.ohio-state.edu /~mgonzalez/Micro521/14.html   (1145 words)

 Intragenic complementation
Genetic analysis initially suggested that HIS4 (called hi-4 in this paper) was polycistronic, analogous to the his operon of E. coli; later it was found to encode a single multifunctional polypeptide with 3 distinct, independently mutable catalytic domains.
Complementation by restoration of the quaternary structure of a multimeric complex: i.e., mutant proteins may not be able to function as homodimers (due to folding or stability problems) but can compensate for each other's defects in heterodimers (Crick and Orgel 1964).
Two alleles display complementation when present on paired homologs, but fail to complement when pairing is disrupted, for example by a translocation.
bio.research.ucsc.edu /people/chisholm/intrageniccomp.html   (516 words)

Genetics of the macronucleus DNA rearrangements during macronuclear differentiation Phenotypic assortment Coassortment Mapping genetically and molecularly the MAC genome 4.
As in other eukaryotes, genetic linkage maps of loci in individual chromosomes are constructed by exploiting the fact that meiotic crossing over generates recombinant genotypes with a frequency which, in the linear portion of the range, is roughly proportional to physical distance [see any genetics textbook, e.g.
For certain natural genetic polymorphisms in surface antigen (serotype), extremely biased initial amplification of one particular allele (in the absence of differential vegetative replication) is sufficient to explain the observed appearance of lack of assortment [27]
lifesci.ucsb.edu /~genome/Tetrahymena/genetics.htm   (7567 words)

 Cellectis : Reverse Genetics
One of the major tasks of genetics is to associate phenotypes with the corresponding mutated genes.
It was this kind of genetics that was performed by people like Johann Gregor Mendel in the 19th century with peas, Thomas H. Morgan in the early 20th with Drosophila, and more recently, by Barbara McClintock with maize.
In many cases (mostly in yeast and mammalian systems), the inactivation of the chosen genes was accomplished by homologous gene targeting, resulting in a complete (or sometimes conditional) knockout of the gene.
www.cellectis.com /reverse.php   (419 words)

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Description: Molecular genetics is an approach to under-standing the functions of genes.
It combines classical genetic analysis with molecu-lar biology to probe the nature of both gene action and gene transmission.
www.scribd.com /doc/46184/ESSENTIALS-OF-MOLECULAR-GENETICS   (802 words)

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