Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Duplication”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
PubMed1992

Mechanism and consequences of the duplication of the human C4/P450c21/gene X locus.

The adjacent C4 and P450c21 genes encode the fourth component of serum complement and steroid 21-hydroxylase respectively, and are tandemly duplicated in the human, murine, and bovine genomes. We recently cloned a cDNA for another duplicated gene, operationally termed X, which overlaps the 3' end of human P450c21 and has the opposite transcriptional orientation. Thus, the organization of the locus is 5'-C4A-21A-XA-C4B-21B-XB-3' (Y. Morel, J. Bristow, S. E. Gitelman, and W. L. Miller, Proc. Natl. Acad. Sci. USA 86:6582-6586, 1989). To determine how this locus was duplicated, we sequenced the DNA at the duplication boundaries and the 7 kb between P450c21A and C4B comprising the XA locus. The sequences located the duplication boundaries precisely and indicate that the duplication occurred by nonhomologous recombination. The boundaries are substantially different from those of the corresponding duplication in the mouse genome, suggesting that similar gene duplications may have occurred independently in ancestors of rodents and primates after mammalian speciation. Compared with XB, the XA gene is truncated at its 5' end and bears a 121-bp intragenic deletion causing a frameshift and premature translational stop signal. Nevertheless, XA is transcribed into a stable 2.6-kb polyadenylated RNA that is expressed uniquely in the adrenal gland.

Adrenal Glands↗
PubMed2002

Gastrointestinal duplications in Ile-Ife, Nigeria.

BACKGROUND: Gastrointestinal duplications are rare congenital malformations that commonly present within the first year of life. When they present in older age groups, diagnosis is often difficult. This difficulty derives from the lack of specific clinical features attributable to these lesions OBJECTIVES: To document the challenges posed to surgeons by gastrointestinal duplications in different parts of the world and to report our experience in its management in Ile-Ife, Nigeria. DESIGN: A retrospective study. It involved a study of the clinical records of all patients diagnosed to have gastrointestinal duplication in our hospital. SETTING: A Paediatric and General Surgical unit, University of Ile-Ife Teaching Hospital, Ile-Ife, Nigeria.. RESULTS: Five patients were diagnosed to have gastrointestinal duplications over the of the study. The ate, ranged from 28 days to 52 years. There were four males and one female. One patient presented within the first month of life. The others presented after the age of one year. There were two gastric, two ileal and one rectal duplication. All had the cystic variety of duplication. Three of the patients had excision, one had mucosal stripping and one had internal drainage of the duplication. The outcome was satisfactory in all of them. CONCLUSION: Duplications tend to present at a much older-age group in our environment. Early diagnosis therefore depends on a high index of suspicion and every surgeon operating in the abdomen must be familiar with the management of this condition.

Adolescent↗
PubMed1999

[Formation of the heterozygous tandem duplication in the process of conjugation recombination in Escherichia coli: study of the effect of mutations for the recQ, uvrD, and recJ genes].

Stable tandem duplications were shown to originate from conjugational recombination between Escherichia coli HfrH strains carrying mutations for the deo operon. The duplications deoC deoD/deoA deoB::Tn5 usually constitute approximately 5% of the Deo+ offspring. The effect of mutations for the recQ, uvrD, and recJ genes on the frequency of duplications was studied. The CM1563 strain carrying the recQ mutation was shown to give, as a recipient, 20% of duplications in the Deo+ offspring. However, this property of CM1563 seems to depend on the presence of a spontaneous mutation of unknown nature, which also increased UV sensitivity of bacteria. The recQ mutation itself increased the frequency of duplications by less than 50%. The recJ mutation did not virtually affect the frequency of duplications. The uvrD mutation possessing the recombinogenic effect was shown to increase the frequency of deo+ recombinants and simultaneously decrease the frequency of duplications. Tandem duplications are assumed to be normal intermediates of multi-stage conjugational recombination initiated by the integration of the proximal region of the Hfr chromosome into different nonhomologous regions of the recipient chromosome.

Conjugation, Genetic↗
PubMed1999

[Prenatal and neonatal management of digestive tract duplications. Diagnostic difficulties and therapeutic implications].

OBJECTIVE: To insist on the difficulty of the antenatal diagnosis of digestive duplications, to show the importance of a complete malformative screening, and the need for immediate management at birth. MATERIAL AND METHODS: A cystic duplication of the tongue, a duplication, abdomino-thoracic transdiaphragmatic, and a duplication of the small bowel are described and compared with cases previously reported in th literature. RESULTS: Antenatal evacuation puncture of a duplication of the tongue must be reserved for exceptional situations. Foregut duplications are often associated with other malformations. The duplication of the small intestine can exceptionally expose to a mechanical complication, mostly during the postnatal period, which may require emergency surgery. CONCLUSION: Duplications of the alimentary tract should be detectable on prenatal ultrasound examination. A complete antenatal malformative screening is required and in utero transfer is warranted because emergency surgery may be required.

Abnormalities, Multiple↗
PubMed2002

[Study of RecA-independent homologous recombination and a chromosomal rearrangement in the Escherichia coli strain carrying an extended tandem duplication].

A heterozygous tandem duplication in the Escherichia coli deo operon region deoA deoB::Tn5/deoC deoD thr::Tn9 with the total length approximately 150 kb, which was obtained in the conjugational mating in the HfrH strain, was examined. By means of digestion with the NotI enzyme, pulsed-field gel electrophoresis, and the conjugational transfer of the duplication in the F- strain, the chromosomal rearrangement, which occurred in the duplication region upon its stabilization in the bacterial genome, was studied. In a more stable strain, two new NotI sites were shown to appear in the chromosomal region located close to the duplication, which might have resulted from the transposition of the IS50 sequence from Tn5. The data were also obtained indicating the possibility of secondary transposition of the chromosomal segment between the two new NotI sites (approximately 30 kb) in the region located near the duplication. With the use of rec+ and recA strains, two types of haploid and diploid segregants generated by the duplication were studied: DeoD+ (the DeoD+ allele is not expressed in the original duplication due to the polar effect of the deoB::Tn5 insertion) and DeoC DeoD. The segregation of DeoD+ clones was shown to be RecA-dependent, whereas the DeoC DeoD segregants selected on the medium that contained thymine at a low concentration (i.e., under conditions of thymine starvation) appeared at a rather high frequency. However, the relative frequency of haploid clones, which have lost the duplication, strongly decreased in the recA genome among segregants of both types.

Chromosomes, Bacterial↗
PubMed2004

Atypical squamous cells, cannot exclude HSIL: a review of original vs. duplicate thin-layer slides.

OBJECTIVE: To assess the utility of consensus review of original ThinPrep slides (Cytyc Corp., Boxborough, Masssachusetts) vs. duplicate slides and to identify the significance of the number of representative cells in classifying atypical squamous metaplastic cells, cannot exclude high grade squamous intraepithelial lesion (ASC-H). STUDY DESIGN: A duplicate ThinPrep slide was prepared from 19 cases of ASC-H. Both original and duplicate slides underwent blinded review by 4 pathologists. Consensus cytologic interpretations (75% agreement) were noted and compared with follow-up diagnoses. Dots with atypical metaplastic cells from each slide were counted and correlated with the consensus cytologic interpretation. RESULTS: Following review of 19 original and 19 duplicate slides, consensus interpretations were reached in 14 and 15 cases, respectively. Nine cases of squamous intraepithelial lesion (SIL) were confirmed by biopsies. Consensus interpretation of original and duplicate slides predicted 7 and 6 cases of SIL, respectively. Consensus interpretation of duplicate slides predicted 60% of histologically benign cases. Two-thirds of nonconsensus cases were histologically benign. Consensus interpretations for high grade SIL were reached more often on slides with greater numbers of atypical squamous metaplastic cells. Fewer abnormal cells were present on the duplicate slides. CONCLUSION: Consensus reviews of original and duplicate slides are equally useful in classifying atypical squamous cells, cannot exclude high grade squamous intraepithelial lesion, but may not be practical in all circumstances. HPV DNA testing of all such cases may better detect clinically significant cases.

Adult↗
PubMed1983

[Urethral duplication in boys. Apropos of 16 new cases].

A total of 16 cases of urethral duplication in boys have been treated over a period of 20 years. Applying the classification described by Innes Williams cases could be divided into: epispadial urethral duplications, hypospadial duplications, spindle urethras, bifid urethras with an accessory preanal branch, and finally collateral duplications. The 16 cases reported were an epispadial double urethra (3 duplicated and 2 bifid) in 5 cases, a hypospadial duplication (4 bifid and 6 blind urethras) in 10 cases, and a bifid urethra with an accessory preanal branch in one case. Not one of the other forms was observed. Treatment of epispadial double urethras consisted mainly of almost total ablation of the supernumerary urethra with freeing of the corpus cavernosum when dorsal incurving developed during erection. The blind forms associated with the hypospadias in hypospadial duplications have no incidence on treatment. In the incomplete forms, treatment is based on four principles: the impossibility of using the superior urethra which extends to the end of the penis, as it is to narrow, implying its opening up to the region facing the hypospadial meatus and the transformation of this incomplete urethral duplication into a single orifice hypospadias; endoscopic resection of the mucosal folds producing a valve effect at the junction between the 2 urethras; the need to straighten an angled penis; and finally the performance of a urethroplasty using the same rules as for surgery of hypospadias. Treatment of bifid urethras with accessory preanal branches depends on the condition of the principal urethra. When this is normal it is sufficient to excise the accessory branch.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Reducing duplicate hand and wrist series in the emergency room: experience at Madigan Army Medical Center.

OBJECTIVE: To demonstrate that repetitive hand or wrist series could be minimized with minor refinements of triage. POPULATION: 2,119 consecutive trauma patients requiring hand or wrist series. METHOD: In baseline phase I, radiographs were ordered by triage corpsmen. In phase II, RNs or physicians performed triage and ordered films. Phase III followed inservice training on strategies to minimize duplicate studies. Phase IV required the RN or physician to provide written justification for duplicate studies. The number of duplications in each phase were compared to baseline using the chi-square test of homogeneity. RESULTS: The phase I duplication rate was 10.8%. In phase II, the percentage of duplicate studies was 8.1% (p = 0.12). Phase III decreased duplication to 6.2% (p < 0.01). Phase IV decreased duplicate studies to 5.8% (p < 0.01). CONCLUSION: In an emergency room generating over 180 hand and wrist studies monthly, minor changes in ordering practices reduced the duplication rate from 10.8% to 5.8%.

Emergency Medical Services↗
PubMed1996

Partial tandem duplication of ALL1 as a recurrent molecular defect in acute myeloid leukemia with trisomy 11.

Gains of a single chromosome are frequent cytogenic findings in human cancer, but no molecular rearrangement has been consistently associated with any trisomy. In acute myeloid leukemia (AML), trisomy 11 (+11) occurring as a sole abnormality is the third most common trisomy. We have shown that the ALL1 gene, located at 11q23, can be rearranged as a result of a partial tandem duplication in two such cases of AML. To test the hypothesis that the partial tandem duplication of ALL1 is the recurrent molecular defect in cases of AML presenting with +11 as a sole cytogenic abnormality, we performed Southern analysis and PCR for defects of ALL1 in 17 cases of AML and one case of myelodysplastic syndrome with +11 or +11q but without cytogenic evidence of a structural abnormality involving 11q23. Twelve cases (67%) had rearrangement of ALL1, including 10 of 11 patients (91%) with +11 as a sole abnormality and 2 of 7 cases (29%) with +11 and other aberrations; all were classified as FAB M1 or M2. In 10 of the 12 cases, material was available for additional characterization; a partial tandem duplication of ALL1 was detected in each of these 10 cases (100%). Four cases demonstrated previously unreported duplications, two of which were detectable only by reverse transcription-PCR. Four patients with the ALL1 duplication also displayed a loss of material from 7q, suggesting an association between these two findings. We conclude that the partial tandem duplication of ALL1 is present in most, if not all, cases of AML with +11 as a sole abnormality, and can be found in cases of AML with +11 or +11q accompanied by other cytogenic abnormalities. The duplication is more prevalent in AML than was recognized previously in part because its size and location vary considerably, requiring a variety of molecular probes for detection. Our finding of the ALL1 duplication as a consistent defect in patients with +11 represents the first identification of a specific gene rearrangement associated with recurrent trisomy in human cancer.

Acute Disease↗
PubMed1997

Diagnosis of CMT1A duplications and HNPP deletions by interphase FISH: implications for testing in the cytogenetics laboratory.

Charcot-Marie-Tooth (CMT) disease type 1A is an inherited peripheral neuropathy characterized by slowly progressive distal muscle wasting and weakness, decreased nerve conduction velocities, and genetic linkage to 17p12. Most (> 98%) CMT1A cases are caused by a DNA duplication of a 1.5-Mb region in 17p12 containing the PMP22 gene. The reciprocal product of the CMT1A duplication is a 1.5-Mb deletion which causes hereditary neuropathy with liability to pressure palsies (HNPP). The most informative current diagnostic testing requires pulsed-field gel electrophoresis to detect DNA rearrangement-specific junction fragments. We investigated the use of interphase FISH for the detection of duplications and deletions for these disorders in the clinical molecular cytogenetics laboratory. Established cell lines or blood specimens from 23 individuals with known molecular diagnoses and 10 controls were obtained and scored using a two-color FISH assay. At least 70% of CMT1A cells displayed three signals consistent with duplications. Using this minimum expected percentile to make a CMT1A duplication diagnosis, all patients with CMT1A showed a range of 71-92% of cells displaying at least three signals. Of the HNPP cases, 88% of cells displayed only one hybridization signal, consistent with deletions. The PMP22 locus from normal control individuals displayed a duplication pattern in approximately 9% of cells, interpreted as replication of this locus. The percentage of cells showing replication was significantly lower than in those cells displaying true duplications. We conclude that FISH can be reliably used to diagnose CMT1A and HNPP in the clinical cytogenetics laboratory and to readily distinguish the DNA rearrangements associated with these disorders from individuals without duplication or deletion of the PMP22 locus.

Cell Line↗
PubMed2004

Genome duplication led to highly selective expansion of the Arabidopsis thaliana proteome.

Multiple ancient genome duplications in Arabidopsis thaliana provide unique opportunities to assess factors that influence the fates of duplicated genes. We have found that genes retained in duplicate following one round of genome duplication are significantly more likely to be retained in duplicate again after a subsequent genome duplication. Genes retained in duplicate form a functionally biased set and include a significant over-representation of genes involved in the regulation of transcription.

Arabidopsis↗
PubMed2002

Analysis of lamprey and hagfish genes reveals a complex history of gene duplications during early vertebrate evolution.

It has been proposed that two events of duplication of the entire genome occurred early in vertebrate history (2R hypothesis). Several phylogenetic studies with a few gene families (mostly Hox genes and proteins from the MHC) have tried to confirm these polyploidization events. However, data from a single locus cannot explain the evolutionary history of a complete genome. To study this 2R hypothesis, we have taken advantage of the phylogenetic position of the lamprey to study the history of gene duplications in vertebrates. We selected most gene families that contain several paralogous genes in vertebrates and for which lamprey genes and an out-group are known in databases. In addition, we isolated members of the nuclear receptor superfamily in lamprey. Hagfish genes were also analyzed and found to confirm the lamprey gene analysis. Consistent with the 2R hypothesis, the phylogenetic analysis of 33 selected gene families, dispersed through the whole genome, revealed that one period of gene duplication arose before the lamprey-gnathostome split and this was followed by a second period of gene duplication after the lamprey-gnathostome split. Nevertheless, our analysis suggests that numerous gene losses and other gene-genome duplications occurred during the evolution of the vertebrate genomes. Thus, the complexity of all the paralogy groups present in vertebrates should be explained by the contribution of genome duplications (2R hypothesis), extra gene duplications, and gene losses.

Animals↗
PubMed2006

Identification and analysis of genes and pseudogenes within duplicated regions in the human and mouse genomes.

The identification and classification of genes and pseudogenes in duplicated regions still constitutes a challenge for standard automated genome annotation procedures. Using an integrated homology and orthology analysis independent of current gene annotation, we have identified 9,484 and 9,017 gene duplicates in human and mouse, respectively. On the basis of the integrity of their coding regions, we have classified them into functional and inactive duplicates, allowing us to define the first consistent and comprehensive collection of 1,811 human and 1,581 mouse unprocessed pseudogenes. Furthermore, of the total of 14,172 human and mouse duplicates predicted to be functional genes, as many as 420 are not included in current reference gene databases and therefore correspond to likely novel mammalian genes. Some of these correspond to partial duplicates with less than half of the length of the original source genes, yet they are conserved and syntenic among different mammalian lineages. The genes and unprocessed pseudogenes obtained here will enable further studies on the mechanisms involved in gene duplication as well as of the fate of duplicated genes.

Animals↗
PubMed2000

Expression of sox11 gene duplicates in zebrafish suggests the reciprocal loss of ancestral gene expression patterns in development.

To investigate the role of sox genes in vertebrate development, we have isolated sox11 from zebrafish (Danio rerio). Two distinct classes of sox11-related cDNAs were identified, sox11a and sox11b. The predicted protein sequences shared 75% identity. In a gene phylogeny, both sox11a and sox11b cluster with human, mouse, chick, and Xenopus Sox11, indicating that zebrafish, like Xenopus, has two orthologues of tetrapod Sox11. The work reported here investigates the evolutionary origin of these two gene duplicates and the consequences of their duplication for development. The sox11a and sox11b genes map to linkage groups 17 and 20, respectively, together with other loci whose orthologues are syntenic with human SOX11, suggesting that during the fish lineage, a large chromosome region sharing conserved syntenies with mammals has become duplicated. Studies in mouse and chick have shown that Sox11 is expressed in the central nervous system during development. Expression patterns of zebrafish sox11a and sox11b confirm that they are expressed in the developing nervous system, including the forebrain, midbrain, hindbrain, eyes, and ears from an early stage. Other sites of expression include the fin buds and somites. The two sox genes, sox11a and sox11b, are expressed in both overlapping and distinct sites. Their expression patterns suggest that sox11a and sox11b may share the developmental domains of the single Sox11 gene present in mouse and chick. For example, zebrafish sox11a is expressed in the anterior somites, and zebrafish sox11b is expressed in the posterior somites, but the single Sox11 gene of mouse is expressed in all the somites. Thus, the zebrafish duplicate genes appear to have reciprocally lost expression domains present in the sox11 gene of the last common ancestor of tetrapods and zebrafish. This splitting of the roles of Sox11 between two paralogues suggests that regulatory elements governing the expression of the sox11 gene in the common ancestor of zebrafish and tetrapods may have been reciprocally mutated in the zebrafish gene duplicates. This is consistent with duplicate gene evolution via a duplication-degeneration-complementation process.

Amino Acid Sequence↗
PubMed2001

Clinical implications of duplicated mtDNA in Pearson syndrome.

We report on a seven-year-old Japanese boy with Pearson syndrome, which is characterized by refractory sideroblastic anemia with vacuolization of marrow precursors and dysfunction of the exocrine pancreas, and caused by mitochondrial (mt) DNA deletions and duplications. Although analysis with Southern hybridization on his bone marrow cells at age one year or on the muscle at age five years did not detect any duplications of mtDNA, an analysis after death at age seven years detected them in the kidney, heart, and even in the bone marrow. Using long PCR to specifically amplify duplicated mtDNA, we found duplications in all biopsy and postmortem samples, indicating that duplications had been present in the patient since his early life, and that the number of duplications increased with age. The results indicate some dynamism in the mtDNA duplication and that the dynamism may imply clinical importance.

Blotting, Southern↗
PubMed2001

The phenotypic manifestations of interstitial duplications of proximal 15q with special reference to the autistic spectrum disorders.

This study investigated the phenotypic manifestations of interstitial duplications of chromosome 15 that involve the Prader-Willi/Angelman syndrome critical region (PWACR). Twenty-one affected individuals from six families were evaluated in detail, using standardized and semi-standardized measures of intelligence, psychopathology, and physical anomalies. Special attention was placed on determining the prevalence of autism spectrum disorders as well as the relationship between the parental origin of the duplication and the phenotypic effects. Assessments of the affected individuals were compared with evaluations of the unaffected relatives from the same families. Results indicated that duplications in the region were associated with variable degrees of intellectual impairments and motor coordination problems. Four of the subjects received a diagnosis of pervasive developmental disorder. Three of these cases were probands and only one met criteria for classic autism. There was very little evidence of the duplication cosegregating with autism spectrum disorder diagnosis. Paternally inherited duplications were significantly less likely to give rise to phenotypic effects. The findings indicate that duplications in the PWACR give rise to developmental delay but not necessarily autism spectrum disorders. They also suggest that phenotypic expression is dependent on the parental origin of the duplication and implicate maternally active genes in the pathogenesis of the developmental impairments. Further research will be required to clarify the range and basis of the phenotypic manifestations.

Adult↗
PubMed2003

Disclosing the mechanisms of origin of de novo short-arm duplications of chromosome 9.

Three de novo short-arm duplications of chromosome 9 were investigated by fluorescence in situ hybridization (FISH) and genotyping of microsatellite loci with the aim of disclosing their mechanisms of origin. Two of these duplications were identified as direct and one as an inverted duplication, and they comprised nearly the entire 9p. In the two dirdup(9p), the distal breakpoints were mapped to subtelomeric sequences, whereas the proximal break boundaries were defined by pericentromeric sequences. The maternal origin of both duplications was demonstrated, and the presence of three different alleles in distal loci indicated that these rearrangements must have occurred prezygotically. In the invdup(9p), the proximal breakpoint was mapped at the alphoid sequences, which were partially duplicated on the tip of the rearranged 9p; subtelomeric and telomeric sequences were not detected, allowing the distal breakpoint to be mapped proximally to subtelomeric sequences. Genotyping of microsatellite loci allowed us to conclude that this invdup(9p) chromosome had a paternal origin. Homozygosity throughout the duplicated segment pointed to its probable postzygotic formation. Chromatid rearrangements appeared to have originated these 9p duplications, involving pericentromeric and subtelomeric sequences. These rearrangements might have been the result of recombination events between homologous repeats in these segments.

Adolescent↗
PubMed2005

From 2R to 3R: evidence for a fish-specific genome duplication (FSGD).

An important mechanism for the evolution of phenotypic complexity, diversity and innovation, and the origin of novel gene functions is the duplication of genes and entire genomes. Recent phylogenomic studies suggest that, during the evolution of vertebrates, the entire genome was duplicated in two rounds (2R) of duplication. Later, approximately 350 mya, in the stem lineage of ray-finned (actinopterygian) fishes, but not in that of the land vertebrates, a third genome duplication occurred-the fish-specific genome duplication (FSGD or 3R), leading, at least initially, to up to eight copies of the ancestral deuterostome genome. Therefore, the sarcopterygian (lobe-finned fishes and tetrapods) genome possessed originally only half as many genes compared to the derived fishes, just like the most-basal and species-poor lineages of extant fishes that diverged from the fish stem lineage before the 3R duplication. Most duplicated genes were secondarily lost, yet some evolved new functions. The genomic complexity of the teleosts might be the reason for their evolutionary success and astounding biological diversity.

Animals↗