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  • chromosome
  • This retrosequence, which is located at 102F on the fourth chromosome, recruited a nearby exon and intron, thereby evolving a chimeric gene structure. (pnas.org)
  • The Xist gene, which is polyadenylated and plays a crucial role in inactivating X chromosome, is also only found in mammals ( 9 , 10 ). (pnas.org)
  • Genetic recombination and deletion mapping of the memory defect placed the gene in a 140-kb stretch in region 11D of the X chromosome ( 4 ). (pnas.org)
  • Mutations
  • Mutations in para affect membrane excitability in Drosophila neurons [Ganetzky, B. & Wu, C.F. (1986) Annu. (pnas.org)
  • Here we identify a novel trxG family member, taranis ( tara ), on the basis of the following criteria: (i) tara loss-of-function mutations act as genetic antagonists of the PcG genes Polycomb and polyhomeotic and (ii) they enhance the phenotypic effects of mutations in the trxG genes trithorax ( trx ), brahma ( brm ), and osa . (genetics.org)
  • Null mutations in most PcG and trxG genes are recessive lethal, but phenotypes may be observed in heterozygous flies as a consequence of HOM misexpression. (genetics.org)
  • The gene pointed (pnt) is required for this glial-neuronal cell interaction, as loss of function mutations lead to a change in the migration behavior of the midline glial cells. (biologists.org)
  • TO discover the function of a gene, a geneticist typically isolates mutations in that gene and evaluates their effects. (genetics.org)
  • It is frequently desirable to be able to introduce targeted mutations to address specific questions about gene function. (genetics.org)
  • Particularly with the sequences of complete genomes of many organisms now available, gene identification is facilitated, but producing directed mutations is often still challenging. (genetics.org)
  • Mutations in meiotic genes, such as the DSB repair genes okra/dRad54 ( okr ) and spindle-A/dRad51 ( spn-A ), delay this restriction. (genetics.org)
  • germ-line
  • Over the past 25 years, gene targeting has been widely used in model eukaryotes, first in yeast and then in mice ( 1 , 2 ), but the difficulty of introducing a linear DNA molecule into germ-line cells hindered its development for Drosophila . (pnas.org)
  • We used this easy-to-score eggshell phenotype in a germ-line mosaic screen in Drosophila to identify new genes affecting meiotic progression, DNA condensation, and Gurken signaling. (genetics.org)
  • The germarium is the most anterior structure of the Drosophila ovariole, where germ-line stem cells produce cystoblasts by asymmetric division. (genetics.org)
  • loci
  • are subsequently maintained by the antagonistic activities of two families of trans -regulator genes, the Polycomb and trithorax group loci (PcG and trxG, respectively). (genetics.org)
  • among genes
  • Additionally, orphans are over-represented among genes related to olfaction, hormonal activity, puparial adhesion, egg membrane structure and perception and response to abiotic stimulus. (uni-koeln.de)
  • Recent reports suggest that levels of codon bias differ among genes that are differentially expressed between the sexes, with male-expressed genes showing less codon bias than female-expressed genes. (genetics.org)
  • These observations cannot be explained by differences in chromosomal distribution, mutational processes, recombinational environment, gene length, or absolute expression level among genes of the different expression classes. (genetics.org)
  • Selection intensity for codon usage bias, therefore, is expected to vary among genes. (genetics.org)
  • induction
  • The level of induction of the diptericin gene in immune-challenged adults varies strikingly with the microorganism tested. (sdbonline.org)
  • The pattern of cecropin A, drosocin, defensin, and attacin induction roughly corresponds to the pattern of diptericin induction Drosophila that are naturally infected by entomopathogenic fungi exhibit an adapted response by producing only peptides (especially drosomycin ) with antifungal activities. (sdbonline.org)
  • Increased induction of ZFN expression led to higher frequencies of gene targeting, demonstrating the beneficial effect of activating the target. (genetics.org)
  • sequences
  • The sequences analyzed included the ORFs of all identified genes in or near the interval ( Fig. 1 A ). In this comparison, we detected only a 1-nt difference between mutant and parent strains, a C-to-T transition in the ORF of the CG15720 ( 11 ) predicted gene. (pnas.org)
  • Because zinc fingers can be directed to a broad range of DNA sequences and targeting is very efficient, this approach promises to allow genetic manipulation of many different genes, even in cases where the mutant phenotype cannot be predicted. (genetics.org)
  • sequence
  • Sequence comparisons suggest that two Na+-channel genes arose early in evolution, before the divergence of vertebrate and invertebrate lines. (pnas.org)
  • A comparison of the CRMs for the Abdominal-B gene from different Drosophila species reveals relatively low levels of overall sequence conservation. (harvard.edu)
  • Gene targeting is the modification of an endogenous gene sequence by recombination between an introduced DNA fragment and the homologous target gene. (pnas.org)
  • Model Organisms
  • Large mutant collections exist for a number of model organisms, but some genes are not represented, and the nature of the alterations is not under the control of the experimenter. (genetics.org)
  • divergence
  • A general model for orphan gene evolution is proposed that takes these large rate differences into account and suggests that they are caused by episodic phases of fast and slow divergence. (uni-koeln.de)
  • Kinase
  • Here we describe the analysis of 8 complementation groups, including Kinesin heavy chain, the SR protein kinase cuaba , the cohesin-related gene dPds5/cohiba , and the Tudor-domain gene montecristo . (genetics.org)
  • unclear
  • How new RNA genes originated and whether this process is controlled by similar evolutionary mechanisms for the origin of protein-coding genes remains unclear. (pnas.org)
  • evolve
  • Thus, these observations give rise to an interesting question: how did new RNA genes originate and evolve throughout the history of gene evolution? (pnas.org)
  • Analysis of substitution rates shows that recovered orphans evolve on average more than three times faster than non-orphan genes, although the width of the evolutionary rate distribution is similar for both classes. (uni-koeln.de)
  • species
  • It has been observed that some ncRNAs only exist in particular lineages or species, suggesting that nature must have independently created these new RNA genes during evolution. (pnas.org)
  • hypothesis
  • In the RNA world, a hypothesis concerning the initial stage of life, RNA genes dominated all life activities ( 1 ). (pnas.org)
  • exon
  • Gilbert speculated that exon shuffling could serve to create new RNA genes in the RNA world ( 11 ). (pnas.org)
  • Indeed, there is ample evidence supporting a common role of exon shuffling in protein-coding genes ( 12 , 13 ). (pnas.org)
  • Second, a wild-type gene was disrupted by the insertion of a marker gene in exon 1 at a rate of ≈1/380 gametes. (pnas.org)
  • microarray
  • Twenty eight genes randomly selected from the microarray-identified list were verified by real time PCR (qPCR) which supported the microarray data. (biomedcentral.com)
  • Most importantly, all genes randomly selected from the microarray-identified list were verified by real time PCR. (biomedcentral.com)
  • codon
  • The nonrandom use of synonymous codons (codon bias) is a well-established phenomenon in Drosophila. (genetics.org)
  • We found that male-biased genes have significantly less codon bias than both female- and non-sex-biased genes. (genetics.org)
  • Presumably, highly expressed genes have more codon bias because selection for translational efficiency and accuracy is stronger in these genes. (genetics.org)
  • chromosomes
  • In region 2, several cells per cyst initiate the assembly of synaptic chromosomes and form DSBs through the activity of the Drosophila SPO11 homologs mei-W68 and mei-P22 . (genetics.org)
  • We show that rolled undergoes polytenization in salivary gland chromosomes to a degree comparable to that of euchromatic genes, despite its deep heterochromatic location. (genetics.org)