• bacteria
  • In free-living bacteria, pseudogenes can make up to 8% of the annotated genes in the genome ( L erat and O chman 2004 ). (genetics.org)
  • Bacteria can occasionally undergo genetic exchange due to the wide variety of accessory genetic elements available to them: integrons and gene cassettes, transposons, plasmids, and phages. (genetics.org)
  • As the rapid spread of antibiotic resistance by horizontal transfer so strikingly and frighteningly illustrates, bacteria can and often will acquire beneficial genes from external sources, so long as these genes exist somewhere in the prokaryotic world ( L evin and B ergstrom 2000 ). (genetics.org)
  • What happens when bacteria are faced with novel or fluctuating environmental conditions and no external sources of beneficial genes are available? (genetics.org)
  • A broad but not mechanistic answer from the classical theory is simply that those populations probably faced environments that fluctuated rapidly enough to favor mutator genes and that such fluctuations may be very common for bacteria. (genetics.org)
  • Different gene expression patterns correlate with the altered phenotype in biofilm-associated bacteria. (nih.gov)
  • The expression of Fe-linked genes (sirR, sitABC operon) in Staphylococcus epidermidis, was compared in planktonic versus sessile bacteria in vitro and in vivo in a subcutaneous foreign body rat model. (nih.gov)
  • Here, we propose a set of reference genes, of the phytopathogenic bacteria Dickeya dadantii and Pectobacterium atrosepticum, which are stable in a wide range of growth conditions. (nih.gov)
  • We measured the expression of these reference gene candidates using quantitative RT-PCR in 50 different experimental conditions, mimicking the environment encountered by the bacteria in their host and directly during the infection process in planta. (nih.gov)
  • Thus, these genes are considered suitable for use as reference genes for the normalization of real-time RT-qPCR data of the two main pectinolytic phytopathogenic bacteria D. dadantii and P. atrosepticum and, probably, of other Enterobacteriaceae. (nih.gov)
  • Moreover, we defined general criteria to select good reference genes in bacteria. (nih.gov)
  • Horizontal gene transfer was first observed in 1928, in Frederick Griffith's experiment: showing that virulence was able to pass from virulent to non-virulent strains of Streptococcus pneumoniae, Griffith demonstrated that genetic information can be horizontally transferred between bacteria via a mechanism known as transformation. (wikipedia.org)
  • There are generally accepted rules and conventions used for naming genes in bacteria. (wikipedia.org)
  • A focus on new model organisms such as viruses and bacteria, along with the discovery of the double helical structure of DNA in 1953, marked the transition to the era of molecular genetics. (wikipedia.org)
  • Upon further investigation, it was discovered that the amino acid composition of HU resembles that of eukaryotic histones, thus prompting further research into the exact function of bacterial DNA binding proteins and discoveries of other related proteins in bacteria. (wikipedia.org)
  • Currently, many more functions of bacteria DNA binding proteins have been discovered, including the regulation of gene expression by histone-like nucleoid-structuring protein, H-NS. (wikipedia.org)
  • H-NS is about 15.6 kDa and assists in the regulation of bacterial transcription in bacteria by repressing and activating certain genes. (wikipedia.org)
  • Attenuation (in genetics) is a proposed mechanism of control in some bacterial operons which results in premature termination of transcription and is based on the fact that, in bacteria, transcription and translation proceed simultaneously. (wikipedia.org)
  • Bacterial genetics is the subfield of genetics devoted to the study of bacteria. (wikipedia.org)
  • Bacterial genetics are subtly different from eukaryotic genetics, however bacteria still serve as a good model for animal genetic studies. (wikipedia.org)
  • Though heritability and variations in bacteria had been noticed from the early days of bacteriology, it was not realised then that bacteria too obey the laws of genetics. (wikipedia.org)
  • The differences in morphology and other properties were attributed by Nageli in 1877, to bacterial pleomorphism, which postulated the existence of a single, a few species of bacteria, which possessed a protein capacity for a variation. (wikipedia.org)
  • However bacteria that are not naturally competent can be treated in such a way to make them competent, usually by treatment with calcium chloride, which make them more permiable Bacterial conjugation is the transfer of genetic material (plasmid) between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells. (wikipedia.org)
  • Again returning to Australia she joined in 1982 the research staff at the CSIRO Molecular and Cell Biology Unit, where she worked on integrons and antibiotic resistance genes which contributed to an understanding of how bacteria become resistant to many antibiotics simultaneously, and to a recognition of the risks posed in increased antibiotic use in medicine and agriculture. (wikipedia.org)
  • After her research unit at CSIRO was closed in 2003 she moved to the University of Sydney as Adjunct Professor in the School of Molecular and Microbial Biosciences, where her research on the molecular genetics and genomics of bacterial antibiotic resistance has identified further mechanisms for gene transfer between gram negative bacteria. (wikipedia.org)
  • This exchange of genes between different bacteria enables rapid emergence of resistance under selection pressure of antibiotics. (wikipedia.org)
  • Spread of resistance between individuals is an increased risk among hospitalized and immunosuppressed patients with Hall's work identifying the role of commensal bacteria, including E.coli in the human colon in the spread of genes. (wikipedia.org)
  • At Stanford he began to explore the field of bacterial plasmids, seeking to understand how the genes of plasmids could make bacteria resistant to antibiotics. (wikipedia.org)
  • He was 33 years old when he won the 1958 Nobel Prize in Physiology or Medicine for discovering that bacteria can mate and exchange genes (bacterial conjugation). (wikipedia.org)
  • Notable contributions include the discovery of the bacterial virus λ, the transfer of genes between bacteria by specialized transduction, the development of replica plating, and the discovery of the bacterial fertility factor F (F plasmid). (wikipedia.org)
  • genomes
  • Bacterial genomes are known to harbor pseudogenes. (genetics.org)
  • For instance, in plant mitochondrial genomes, which have an α-proteobacterial ancestry, most, if not all, of the laterally transferred genes are pseudogenes ( R ichardson and P almer 2007 ). (genetics.org)
  • and most of them are transient in bacterial genomes ( L erat and O chman 2005 ). (genetics.org)
  • reported that genomes with truncated homologs might erroneously lead to false inferences of "gene gain" rather than multiple instances of "gene loss. (genetics.org)
  • Also, as HGT can bring into genomes radically different genotypes from distant lineages, or even new genes bearing new functions, it is a major source of phenotypic innovation and a mechanism of niche adaptation. (wikipedia.org)
  • There are currently over 20,000 bacterial genomes sequenced, and bioinformatics methods can be used to find all BMC shell genes and to look at what other genes are in the vicinity, producing a list of potential BMCs. (wikipedia.org)
  • In the last decades of the 20th century, many biologists focused on large-scale genetics projects, sequencing entire genomes. (wikipedia.org)
  • If the combination of two genomes containing different recessive mutations yields a mutant phenotype, then there are three possibilities: Mutations occur in the same gene. (wikipedia.org)
  • plasmid
  • Subsequent experiments that transferred Staphylococcus plasmid genes into E. coli demonstrated that genes could be transplanted between species. (wikipedia.org)
  • Today, Cohen is a professor of genetics and medicine at Stanford, where he works on a variety of scientific problems involving cell growth and development, including mechanisms of plasmid inheritance and evolution. (wikipedia.org)
  • alleles
  • And, until recently, all was in place: intuition, formal theory, and experimental observations all supported the proposition that although higher rates of mutation can appear occasionally, mutation rates in bacterial populations would remain low and mutator alleles (alleles elevating the genomic mutation rate) would not be selected. (genetics.org)
  • The field also includes studies of intragenomic (within the genome) phenomena such as epistasis (effect of one gene on another), pleiotropy (one gene affecting more than one trait), heterosis (hybrid vigour), and other interactions between loci and alleles within the genome. (wikipedia.org)
  • In this species, wild type flies have red eyes and eye color is known to be related to two genes, A and B. Each one of these genes has two alleles, a dominant one that codes for a working protein (A and B respectively) and a recessive one that codes for a malfunctioning protein (a and b respectively). (wikipedia.org)
  • Proteins
  • Among the 49 genes, 22 encode metabolic enzymes, 9 genes encode membrane proteins involved in membrane traffic and 6 are predicted to encode transcriptional regulators, the others encoding hypothetical proteins or proteins with unknown function. (nih.gov)
  • For many genes and their corresponding proteins, an assortment of alternate names is in use across the scientific literature and public biological databases, posing a challenge to effective organization and exchange of biological information. (wikipedia.org)
  • But owing to the nature of how science has developed (with knowledge being uncovered bit by bit over decades), proteins and their corresponding genes have not always been discovered simultaneously (and not always physiologically understood when discovered), which is the largest reason why protein and gene names do not always match, or why scientists tend to favor one symbol or name for the protein and another for the gene. (wikipedia.org)
  • Also owing to the nature of how scientific knowledge has unfolded, proteins and their corresponding genes often have several names and symbols that are synonymous. (wikipedia.org)
  • Lastly, some proteins and protein complexes are built from the products of several genes (each gene contributing a polypeptide subunit), which means that the protein or complex will not have the same name or symbol as any one gene. (wikipedia.org)
  • Bacterial microcompartments (BMCs) are organelles consisting of a protein shell that encloses enzymes and other proteins. (wikipedia.org)
  • But then genes coding for proteins homologous to those of the carboxysome shell were identified in the pdu (propanediol utilization) and eut (ethanolamine utilization) operons. (wikipedia.org)
  • Although the carboxysome, propanediol utilizing (PDU), and ethanolamine utilizing (EUT) BMCs encapsulate different enzymes and therefore have different functions, the genes encoding for the shell proteins are very similar. (wikipedia.org)
  • Most of the genes (coding for the shell proteins and the encapsulated enzymes) from experimentally characterized BMCs are located near one another in distinct genetic loci or operons. (wikipedia.org)
  • In molecular biology, bacterial DNA binding proteins are a family of small, usually basic proteins of about 90 residues that bind DNA and are known as histone-like proteins. (wikipedia.org)
  • Since bacterial binding proteins have a diversity of functions, it has been difficult to develop a common function for all of them. (wikipedia.org)
  • in these processes, bacterial DNA binding proteins have an architectural role, maintaining structural integrity as transcription, recombination, replication, or any other DNA-dependent process proceeds. (wikipedia.org)
  • Initially, bacterial DNA binding proteins were thought to help stabilize bacterial DNA. (wikipedia.org)
  • species
  • Sequence composition-based ("parametric") methods search for deviations from the genomic average whereas evolutionary history-based ("phylogenetic") approaches identify genes whose evolutionary history significantly differs from that of the host species. (wikipedia.org)
  • Finally, the computational costs of reconstructing many gene/species trees can be prohibitively expensive. (wikipedia.org)
  • The advent of the information age has brought gene ontology, which in some ways is a next step of gene nomenclature, because it aims to unify the representation of gene and gene product attributes across all species. (wikipedia.org)
  • In addition to species-specific databases, approved gene names and symbols for many species can be located in the National Center for Biotechnology Information's "Entrez Gene" database. (wikipedia.org)
  • Examples of bacterial species that have been found to possess multiple replicons include: Rhodobacter sphaeroides (2), Vibrio cholerae, and Burkholderia multivorans (3). (wikipedia.org)
  • Attenuation is an ancient regulatory system, prevalent in many bacterial species providing fast and sensitive regulation of gene operons and is commonly used to repress genes in the presence of their own product (or a downstream metabolite). (wikipedia.org)
  • Heritability means the information in a given gene is not always exactly the same in every individual in that species, so the same gene in different individuals does not give exactly the same instructions. (wikipedia.org)
  • lateral gene tra
  • Truncated genes could also arise from small-scale lateral gene transfer events. (genetics.org)
  • Pseudogenes could also result from the degradation of transferred genes and might even be acquired directly via lateral gene transfer. (genetics.org)
  • A putative methylase (xorIIM) found in 'Ca. Phytoplasma australiense' appeared to have no analogue in any other firmicute, and we believe has been introduced by way of lateral gene transfer. (nih.gov)
  • Horizontal or lateral gene transfer (HGT or LGT) is the transmission of portions of genomic DNA between organisms through a process decoupled from vertical inheritance. (wikipedia.org)
  • Operon
  • Mutations which knocked out the trp R (repressor) gene still showed some regulation of the trp operon (these mutants were not fully induced/repressed by tryptophan). (wikipedia.org)
  • When the sequence of the beginning of the trp operon was determined an unusual open reading frame (ORF) was seen immediately preceding the ORFs for the known structural genes for the tryptophan biosynthetic enzymes. (wikipedia.org)
  • resistance genes
  • In this study, we compared the structure of the fecal microbiota between feral and domestic goats using the G2 PhyloChip and assessed the presence of five tetracycline resistance genes [ tet (M), tet (S), tet (O), tet (Q) and tet (W)] by PCR. (mdpi.com)
  • Both feral and domestic goats carried antibiotic resistance genes tet (O) and tet (W), but domestic goats additionally carried tet (Q). Diet, host genetics and antibiotic exposure are likely determinant factors in shaping the intestinal microbiota and may explain the differences observed between feral and domestic goats fecal microbiota. (mdpi.com)
  • A complex relationship between hypersensitive response and pathogenicity genes, avirulence genes, and plant resistance genes gives rise to the virulence of bacterial pathogens. (wikipedia.org)
  • Resistance genes can also reach the human food chain through subtherapeutic antibiotic use as growth promotants in animal production, with Hall contributing to JETACAR (Joint Expert Advisory Committee on Antibiotic Resistance), which, in 2000, developed Australian Government policy on antibiotic use in agriculture. (wikipedia.org)
  • integrons
  • Bacterial superintegrons, a source of new genes with adaptive functions Ilyina, T. 2006-11-07 00:00:00 Data on the structural organization of the platform of integrons, gene cassettes, and integrons with integrated cassettes of genes encoding drug resistance are briefly summarized. (deepdyve.com)
  • Data obtained during recent years about superintegrons or chromosomal integrons, characteristics of their organization, the presence of genes with known adaptive and unidentified functions in them, as well as data on the differences between superintegrons and previously described multiple resistance integrons, are considered in more detail. (deepdyve.com)
  • Studies that provide evidence for translocations of gene cassettes from stationary chromosomal integrons into integrons associated with mobile elements resulting in gene flows in natural bacterial populations, which favors their survival and adaptation to changing environment, are also reviewed. (deepdyve.com)
  • Data on the structural organization of the platform of integrons, gene cassettes, and integrons with integrated cassettes of genes encoding drug resistance are briefly summarized. (deepdyve.com)
  • Gene cassettes are mobile genetic units each carrying only one gene which can be readily transferred into and between larger, stable genetic backbones called integrons that are responsible for moving the cassettes. (wikipedia.org)
  • candidate genes
  • Because of their complementary approaches-and often non-overlapping sets of HGT candidates-combining predictions from parametric and phylogenetic methods can yield a more comprehensive set of HGT candidate genes. (wikipedia.org)
  • Common uses of bioinformatics include the identification of candidate genes and single nucleotide polymorphisms (SNPs). (wikipedia.org)
  • genome
  • Gene truncation or gene pseudogenization also plays an important role in shaping bacterial genome content. (genetics.org)
  • The estimates also suggest that many truncated genes are in the process of being eliminated from the genome. (genetics.org)
  • Analysis using the new model not only provides more accurate estimates on gene gains/losses (or insertions/deletions), but also reduces any concern of a systematic bias from applying simplified models to bacterial genome evolution. (genetics.org)
  • This will not only yield more accurate estimates of the rates of gene insertions/deletions, but also provide a quantitative view of the effect of truncated genes on rate estimation, which has been understudied in bacterial genome evolution. (genetics.org)
  • The need to develop formal guidelines for human gene names and symbols was recognized in the 1960s and full guidelines were issued in 1979 (Edinburgh Human Genome Meeting). (wikipedia.org)
  • A genome is an organism's complete set of DNA, including all of its genes. (wikipedia.org)
  • Major research efforts in the field include sequence alignment, gene finding, genome assembly, drug design, drug discovery, protein structure alignment, protein structure prediction, prediction of gene expression and protein-protein interactions, genome-wide association studies, the modeling of evolution and cell division/mitosis. (wikipedia.org)
  • loci
  • gene map one showing the positions of genetic loci on the chromosomes and usually giving some indication of the distance between loci. (thefreedictionary.com)
  • Recently a comprehensive survey identified 23 different loci encoding up to 10 functionally distinct BMCs across 23 bacterial phyla. (wikipedia.org)
  • protein
  • Phylogenetic methods tend to be applied to genes or protein sequences as basic evolutionary units, which limits their ability to detect HGT in regions outside or across gene boundaries. (wikipedia.org)
  • Any name or symbol used for a protein can potentially also be used for the gene that encodes it, and vice versa. (wikipedia.org)
  • Regarding the first duality (same symbol and name for gene or protein), the context usually makes the sense clear to scientific readers, and the nomenclatural systems also provide for some specificity by using italic for a symbol when the gene is meant and plain (roman) for when the protein is meant. (wikipedia.org)
  • Depending on the metabolic conditions, the attenuator either stops transcription at that point or allows read-through to the structural gene part of the mRNA and synthesis of the appropriate protein. (wikipedia.org)
  • It also plays a role in the analysis of gene and protein expression and regulation. (wikipedia.org)
  • For example, there are methods to locate a gene within a sequence, to predict protein structure and/or function, and to cluster protein sequences into families of related sequences. (wikipedia.org)
  • In the donor cell, a repressor protein encoded by the prophage (viral DNA) keeps the viral genes turned off so that virus is not produced. (wikipedia.org)
  • sequence
  • Inferring horizontal gene transfer through computational identification of HGT events relies upon the investigation of sequence composition or evolutionary history of genes. (wikipedia.org)
  • Genes inside the nucleus of a cell are strung together in such a way that the sequence carries information: that information determines how living organisms inherit various features (phenotypic traits). (wikipedia.org)
  • Expression
  • 2016. Human MicroRNA-602 Inhibits Hepatits C Virus Genotype 1b Infection and Promotes Tumor Suppressor Gene Expression in a Hepatoma Cell Line. (claflin.edu)
  • Gene expression is quantified as log10 (cDNA/gDNA) in the y-axis. (nih.gov)
  • A reliable normalization of the data, using several reference genes, is critical for an accurate quantification of gene expression.The two most stable genes (ABF-0017965 (lpxC) and ABF-0020529 (yafS) were successfully used for normalization of RT-qPCR data.We have identified at least two genes, lpxC (ABF-0017965) and yafS (ABF-0020509), whose expressions are stable in a wide range of growth conditions and during infection. (nih.gov)
  • Quantitative RT-PCR is the method of choice for studying, with both sensitivity and accuracy, the expression of genes. (nih.gov)
  • A reliable normalization of the data, using several reference genes, is critical for an accurate quantification of gene expression. (nih.gov)
  • We extracted, from a D. dadantii micro-array transcript profile dataset comprising thirty-two different growth conditions, an initial set of 49 expressed genes with very low variation in gene expression. (nih.gov)
  • Out of these, we retained 10 genes representing different functional categories, different levels of expression (low, medium, and high) and with no systematic variation in expression correlating with growth conditions. (nih.gov)
  • Expression profiles of the 10 genes selected for the stability of their expression level and the synthetic RNA pAW.Gene expression profiles are measured from micro-arrays (A) and from quantitative real time RT-PCR (B). The first 32 conditions are those measured in exponential phase and the last 32 conditions are those measured in stationary phase. (nih.gov)
  • by the 1970s gene expression could be controlled and manipulated through genetic engineering. (wikipedia.org)
  • Most of these attenuators are inhibitory and are employed by genes for biosynthetic enzymes or transporters whose expression is inversely related to the concentration of their corresponding metabolites. (wikipedia.org)
  • The integron is also responsible for expression of the genes in cassettes. (wikipedia.org)
  • The genetic code not only controls inheritance: it also controls gene expression, which occurs when a portion of the double helix is uncoiled, exposing a series of the nucleotides, which are within the interior of the DNA. (wikipedia.org)
  • evolution
  • Bacterial gene content variation during the course of evolution has been widely acknowledged and its pattern has been actively modeled in recent years. (genetics.org)
  • We propose an alternative to the models developed in this recent renaissance of mutator gene evolution theory and offer a resolution to the following problem. (genetics.org)
  • Alongside experimental work, mathematicians developed the statistical framework of population genetics, bringing genetic explanations into the study of evolution. (wikipedia.org)
  • Hall's recent work has identified large antibiotic resistance gene clusters, including genomic resistance islands in Salmonella, Klebsiella pneumonia and in Acinetobacter baumanni and examined their evolution. (wikipedia.org)
  • phylogeny
  • Although not a primary purpose, the model incorporating truncated genes could be potentially used for phylogeny reconstruction using gene family content. (genetics.org)
  • Isolates
  • Cr6+ Resistant and Reduction of Bacterial Isolates from Savannah River Site Soil Sample. (claflin.edu)
  • A putative methylase (xorIIM) found in 'Ca.A putative retrostransposon (ltrA) analogous to that found in OY-M was present in both isolates, although all examples in PAa appear to be fragments.This comparative analysis has yielded clues as to how rearrangements occur, and the identification of sets of genes that appear to be associated with these events. (nih.gov)
  • The difference in size between the two isolates was largely due to the number and size of potential mobile units (PMUs), which contributed to some changes in gene order. (nih.gov)
  • Humans
  • Humans have two copies of each of their genes, and make copies that are found in eggs or sperm-but they only include one copy of each type of gene. (wikipedia.org)
  • chromosomes
  • In the 1940s and early 1950s, experiments pointed to DNA as the portion of chromosomes (and perhaps other nucleoproteins) that held genes. (wikipedia.org)
  • processes
  • The lab uses both forward and reverse genetics to identify bacterial genes involved in these processes and to elucidate gene function. (claflin.edu)
  • The risks of the rise of "superbugs" from the gene exchange processes described by Hall are recognized internationally as a threat to human health (WHO report on antibiotic resistance, May 2014). (wikipedia.org)
  • Its use was key to defining most of the genes of the virus, and provided the foundation for the study of such fundamental processes as DNA replication and repair, and how molecular machines are constructed. (wikipedia.org)
  • mutations
  • When clones carrying mutator genes are rare, however, these beneficial mutations are far more likely to arise in members of the much larger nonmutator population. (genetics.org)
  • In genetics, complementation occurs when two strains of an organism with different homozygous recessive mutations that produce the same mutant phenotype (for example, a change in wing structure in flies) produce offspring with the wild-type phenotype when mated or crossed. (wikipedia.org)
  • Complementation will occur only if the mutations are in different genes. (wikipedia.org)
  • A complementation test (sometimes called a "cis-trans" test) can be used to test whether the mutations in two strains are in different genes. (wikipedia.org)
  • Complementation will not occur if the mutations are in the same gene. (wikipedia.org)
  • The convenience and essence of this test is that the mutations that produce a phenotype can be assigned to different genes without the exact knowledge of what the gene product is doing on a molecular level. (wikipedia.org)
  • variation
  • Unfortunately, the information of truncated genes has not been considered in any existing mathematical models on gene content variation. (genetics.org)
  • Rate variation among genes is allowed in the model by incorporating a discrete Γ-distribution. (genetics.org)
  • Despite being 80 kbp larger than another 'Ca. Phytoplasma australiense' isolate PAa, the variation between housekeeping genes was generally less than 1% at a nucleotide level. (nih.gov)
  • Stanford
  • She traveled west to California, and after a summer studying at Stanford University's Hopkins Marine Station under Cornelius Van Niel, she entered a master's program in genetics. (wikipedia.org)
  • 1953
  • She first reported the discovery in 1951 while she was a PhD student and later provided a detailed description in a 1953 paper in the journal Genetics. (wikipedia.org)
  • nomenclature
  • Gene nomenclature is the scientific naming of genes, the units of heredity in living organisms. (wikipedia.org)
  • Drosophila fruit flies, Mus mice) have adopted nomenclature standards, as well, and have published them on the relevant model organism websites and in scientific journals, including the Trends in Genetics Genetic Nomenclature Guide. (wikipedia.org)
  • Scientists familiar with a particular gene family may work together to revise the nomenclature for the entire set of genes when new information becomes available. (wikipedia.org)
  • The HUGO Gene Nomenclature Committee is responsible for providing human gene naming guidelines and approving new, unique human gene names and symbols (short identifiers typically created by abbreviating). (wikipedia.org)
  • different
  • while a different allele of the same gene in a different individual could give garbled instructions that would result in a failure to produce any pigment, giving white hair and no pigmented skin: albinism. (wikipedia.org)
  • The complementation test was one of the main tools used in the early Neurospora work, because it was easy to do, and allowed the investigator to determine whether any two nutritional mutants were defective in the same, or different genes. (wikipedia.org)
  • generally
  • Generally, a single avirulence gene (in the bacterium) corresponds to a single resistance gene (in the plant host), giving rise to the concept of a gene-for-gene response. (wikipedia.org)