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PubMed1996

Duplication of an amphioxus myogenic bHLH gene is independent of vertebrate myogenic bHLH gene duplication.

Gene duplication is thought to be a major genetic change that may have permitted the evolution of vertebrates from invertebrates. The myogenic genes encode basic helix-loop-helix (bHLH) transcriptional factors essential for the formation of skeletal muscle. The invertebrate genome contains only a single myogenic bHLH gene, whereas the vertebrate genome contains four (MyoD, Myf-5, myogenin and MRF4). Since the tunicate genome contains a single myogenic bHLH gene, its duplication might have occurred some time during chordate evolution. To determine whether the duplication of the myogenic bHLH gene occurred prior to, or after the divergence of vertebrates from the cephalochordate lineage, we amplified target fragments from the amphioxus, Branchiostoma floridae, by means of PCR. Sequence analysis and genomic Southern analysis revealed that the amphioxus genome contains two myogenic bHLH genes (BMD1 and BMD2). A comparison of the amino acid sequences in the bHLH domain between BMD1, BMD2 and four vertebrate myogenic bHLH gene products, however, showed that neither BMD1 nor BMD2 resembled any of the four genes. These results suggested that the duplication of amphioxus myogenic bHLH gene occurred independently of that leading to the four myogenic bHLH genes in vertebrates.

Amino Acid Sequence↗
PubMed1985

Duodenal duplication cyst causing massive bleeding in an adult: an unusual complication of a duplication cyst of the digestive tract.

Duodenal duplication cysts are rare malformations that characteristically manifest with intestinal obstruction. In a 50-year experience, we found a duodenal duplication cyst in only three patients, one of whom had massive gastrointestinal bleeding as the initial symptom. Six other duplication cysts (two esophageal, one jejunal, and three ileal) were found. All patients who had extraduodenal intestinal cysts were neonates or infants who initially had an abdominal mass or obstruction. Of the two patients with an esophageal cyst, one had odynophagia and the other had respiratory obstruction. Unusual features of our series of patients were male preponderance (eight of nine patients), the low incidence of other developmental abnormalities, and, in the patients with the duodenal cysts, an age of 14 years or older at the time of onset of symptoms and diagnosis. In an adult, a duodenal duplication cyst may cause upper gastrointestinal hemorrhage. This cause of gastrointestinal bleeding should be considered in the differential diagnosis if an intramural duodenal mass is detected within the medial wall of the second portion of the duodenum distal to the papilla of Vater.

Adult↗
PubMed2000

Spindle pole body duplication: a model for centrosome duplication?

The yeast spindle pole body (SPB) is the functional equivalent of the centrosome and forms the two poles of the mitotic spindle. Before mitosis, both SPBs and centrosomes are present as single copies and must be duplicated to form the bipolar spindle. SPB components have been identified using a combination of biochemistry and genetics, and their role during SPB duplication has been analysed using temperature-sensitive mutants. In this article, we describe structural aspects of SPB duplication and their possible relationship to centrosome duplication.

Centrosome↗
PubMed1986

An unusual alimentary duplication cyst at the floor of the mouth--a proposal of new criteria for alimentary duplications.

In a 11-month-old boy, a cyst lined with non-keratinising stratified squamous epithelium and surrounded by striated muscle bundles with respiratory elements was found at the floor of the mouth. The cyst was excised without complications. As the cyst wall resembles the structure of the upper oesophagus, we think that this may be an alimentary duplication cyst, although it does not satisfy Lister's proposed criteria for alimentary duplications. To our knowledge, intraoral duplication cysts similar to the upper oesophageal tissue have not been reported previously. From the experience of this case, we propose new criteria for alimentary duplications.

Choristoma↗
PubMed1989

Duplication mutation as an SOS response in Escherichia coli: enhanced duplication formation by a constitutively activated RecA.

The SOS response in Escherichia coli involves the induction of a multioperon regulatory system, which copes with the presence of DNA lesions that interfere with DNA replication. Induction depends on activation of the RecA protein to cleave the LexA repressor of SOS operons. In addition to inducible DNA repair, the SOS system produces a large increase in the frequency of point mutations. To examine the possibility that other types of mutations are induced as part of the SOS response, we have studied the production of tandem duplications. To avoid the complications of indirect effects of the DNA lesions, we have activated the SOS response by a constitutive mutation in the recA gene, recA730. The introduction of the recA730 mutation results in an increase in duplications in the range of tenfold or greater, as judged by two different criteria. Based on its genetic requirements, the pathway for induced duplication formation is distinct from the point mutation pathway and also differs from the major normal recombination pathway. The induction of pathways for both duplications and point mutations shows that the SOS system produces a broad mutagenic response. We have suggested previously that many types of mutations might be induced by severe environmental stress, thereby enhancing genetic variation in an endangered population.

DNA Repair↗
PubMed1994

Partial trisomy of the short arm of chromosome 18 due to inversion duplication and direct duplication.

We report one patient with a de novo inversion duplication 18 (pter-->cen) and two cases of direct tandem duplication 18 (pter-->cen), one due to maternal inheritance and the other arising as mosaicism of unknown origin. The duplications are demonstrated by high resolution banding. They were verified by in situ hybridization with a paint specific for chromosome 18 and with DNA probe LI.84 specific for the centromere region of chromosome 18. FISH with the genomic DNA probe pHRR68 specific for 18p11.32 revealed a subtle deletion concomitantly involved in the case of inversion duplication 18p. The patients exhibit slight developmental delay/moderate mental retardation and only a few dysmorphic features. The literature on trisomy 18p is reviewed and the present cases are compared to it.

Abnormalities, Multiple↗
PubMed1996

A case of duplication of 13q32-->qter and deletion of 18p11.32-->pter with mild phenotype: Patau syndrome and duplications of 13q revisited.

A mild clinical phenotype is described in a patient with duplication of 13q32-->qter and a small deletion of 18p11.32-->pter. The 8 year old white male presented with psychomotor retardation, tethered cord, soft, fleshy ears, and normal facial features except for thin lips. The karyotype was found to be 46, XY, der(18)t(13;18) (q32;p11.32) pat confirmed by fluorescence in situ hybridisation (FISH). A review of earlier studies showed that features of trisomy 13 are found in cases of duplication of bands 13q14 to qter. None of the cardinal features of trisomy 13 was seen in this patient. The absence of polydactyly, hernias, urogenital abnormalities, and haemangiomas contrast this condition with both trisomy 13 and duplication of 13q14-22-->qter. Possible explanations for lack of Patau syndrome in this patient could include restriction of the critical region for Patau syndrome to duplication 13q14-->13q32 with variable expression, gene interactions, or interchromosomal effects.

Child↗
PubMed2003

Basilar artery duplication associated with pituitary duplication: a new finding.

Pituitary duplication is a rare malformation, reported previously in approximately 18 patients. It is usually unsuspected before imaging, although it occurs most commonly in association with complicated midline and skull base anomalies. It is easily shown by MR imaging. Five new cases of pituitary duplication were diagnosed by using MR imaging studies reviewed at the Hospital for Sick Children. Among the many associated midline abnormalities, partial basilar artery duplication is a previously undescribed finding that we observed in all our cases. Cases of basilar artery duplication or fenestration are associated with altered flow dynamics, leading to a higher incidence of aneurysms. Periodic surveillance for this potential complication may be warranted.

Basilar Artery↗
PubMed2004

Segmental duplication associated with the human-specific inversion of chromosome 18: a further example of the impact of segmental duplications on karyotype and genome evolution in primates.

The human-specific pericentric inversion of chromosome 18 was analysed using breakpoint-spanning BACs from the chimpanzee and human genome. Sequence and FISH analyses disclosed that the breakpoints map to an inverted segmental duplication of 19-kb, which most likely mediated the inversion by intrachromosomal homologous recombination. The 19-kb duplication encompasses the 3' end of the ROCK1 gene and occurred in the human lineage. Only one copy of this segment is found in the chimpanzee. Due to the inversion, the genomic context of the ROCK1 and USP14 genes is altered. ROCK1 flanks USP14 in the long arm of the chimpanzee chromosome 17, which is homologous to human chromosome 18. This order is interrupted by the inversion in humans. ROCK1 is localized close to the pericentromeric region in 18q11 and USP14 is inverted to distal 18p11.3 in direct neighbourhood to LSAU-satellites, beta-satellites and telomere-associated repeats. Our findings essentially confirm the analysis of Dennehey et al. (2004). Intriguingly, USP14 is differentially expressed in human and chimpanzee cortex as well as fibroblast cell lines determined previously by the analysis of oligonucleotide arrays. Either position effects mediated by the proximity to the telomeric region or nucleotide divergence in regulatory regions might account for the differential expression of USP14. The assignment of the breakpoint region to a segmental duplication underlines the significance of the genomic architecture in the context of genome and karyotype evolution in hominoids.

Animals↗
PubMed1981

Squamous cell carcinoma arising in a duplication of the colon: case report and literature review of squamous cell carcinoma of the colon and of malignancy complicating colonic duplication.

A case of squamous cell carcinoma arising in a duplication of the colon is reported, and the literature of squamous cell carcinoma of the colon and of malignancy complicating duplications of the colon is reviewed. This is the 23rd case of "pure" squamous cell carcinoma of the colon to be reported, and the second reported as arising in a duplication of the colon. Several possible mechanisms for the development of a squamous cell carcinoma in the colon are discussed.

Carcinoma, Squamous Cell↗
PubMed1978

Effects of chemical and physical mutagens on the frequency of a large genetic duplication in Salmonella typhimurium. I. Induction of duplications.

In Salmonella typhimurium a simple selection has been described to detect bacteria that are merodiploid for almost one-third of the chromosome. The selective procedure is based upon improved utilization of L-malate as the sole carbon source in merodiploid strains. The spontaneous frequency of the duplication in haploid strains is approximately 10(-4) per cell plated. Following the exposure of a haploid strain to mutagenic agents, there is a dose-dependent increase in the duplication frequency above the spontaneous level. In this paper we describe the induction of genetic duplications in Salmonella typhimurium by X-rays, ultraviolet light (UV), ethyl methanesulfonate (EMS), nitrous acid, and the azaacridine half mustard, ICR-372.

Acridines↗
PubMed2006

Unusual case of bladder duplication: complete duplication in coronal plane with single urethra and no associated anomalies.

Duplication of the bladder is an unusual congenital anomaly. Complete and incomplete forms are well defined in published reports. We present an unusual case of a 3-year-old boy with two separate-walled bladders, one lying in front of the other, communicating through a tiny septum, at the neck of the primary bladder that drained to a normal single urethra. This type of isolated bladder anomaly was not defined in the classification of the duplication of the bladder. In patients with a lower abdominal cystic mass, complete bladder duplication must be included in the differential diagnosis of pelvic cystic masses.

Child, Preschool↗
PubMed1983

Incomplete renal duplication obscuring ipsilateral complete duplication.

Renal duplication is not an uncommon anomaly of the urinary tract. However, we report a case in which the occurrence of incomplete duplication of a large lower pole, with an unusual side-by-side orientation of the lower pole segments, delayed recognition of the clinically troublesome ipsilateral upper pole duplication.

Child, Preschool↗
PubMed2003

Duplication of pouch colon associated with duplication of the lower genitourinary tract.

The authors report on a baby with imperforate anus associated with duplication of descending colon, double pouch colon type IV, duplication of the urinary bladder, and a bifid penis. The interesting presentation of this problem and its management is discussed with a brief review of the probable embryologic basis for such an anomaly. Such a duplication of pouch colon has not been described previously.

Colon↗
PubMed1998

Mutants and duplication in chromosome 7 (syn. 5H) in the barley line HA21: duplications may enhance QTLs and serve to make constant linear cis-heterozygosity.

Cytological and linkage data indicate a duplication in the short arm of chromosome 7 (syn. 5H) in the mutant line HA21 (barley, Hordeum vulgare, cv. 'Pirkka'). The associated mutant (ha21) shows a weighted average linkage of 22.1 cM with pld, hitherto an ignored anthocyaninless gene, of cv. Pirkka. Some crosses produce F2 segregants with an exaggerated ha21 phenotype which may represent position effect or increased dosage of the mutant gene through recombination. Compared with cv. Pirkka, HA21 has changes in grain chemistry (alpha- and beta-amylase, beta-glucanase), which may be caused by changed QTL dosage or QTL position effect due to duplication. The use of duplication in creating constant +m/+ m or m+/m+ linear cis-heterozygotes is suggested. Linear cis-heterozygotes may produce stable heterosis or attenuate the undesired effects of drastic mutants.

Chromosome Mapping↗
PubMed1977

Duplication variables related to partial denture castings. 1. The duplicating flask.

A metal die simulating a model of a partially dentate upper jaw prepared with milled facets for reference measurement with vernier calipers was used for the making of duplicate stone models, in three different duplicating flasks. The observation showed that irrespective of the flask size, the duplicated models were slightly wider.

Dental Casting Technique↗