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 1,297 records · Page 72Linked to original sources
PubMedDate not supplied

Duplicated plastid and triplicated cytosolic isozymes of triosephosphate isomerase in maize (Zea mays L.).

We studied electrophoretic variation and inheritance of triosephosphate isomerase (TPI) isozymes in maize (Zea mays L.). In contrast to most diploid plants, in maize, TPI exists as multiple isozymes in both the plastid and cytosolic subcellular compartments. Phenotypes result from the overlay of two independent sets of isozymes and allozymes, representing the plastid (encoded by the nuclear genes Tpi1 and Tpi2) and cytosolic (encoded by Tpi3, Tpi4, and Tpi5) systems. All possible intragenic and intergenic dimeric enzymes are formed between polypeptides within each subcellular compartment. No heterodimers are formed between plastid and cytosolic polypeptides. Extensive surveys of accessions of land races and inbred lines revealed 22 allelic variants for the five loci. Most alleles have been formally validated by segregation analysis. We describe two null alleles at Tpi4, distinguished by their relative abilities to form intergenic heterodimers with polypeptides specified by Tpi3 and Tpi5. Linkage analyses and crosses with B-A translocation stocks were effective in determining the chromosome locations of all five loci. Duplicated genes for both the plastid and cytosolic isozymes were localized to genomic regions that possess numerous other redundant sequences. We placed Tpi1 on the long arm of chromosome 7, approximately 23 centimorgans (cM) distal to g11; we localized its duplicate--Tpi2--17 cM distal to v4 on the long arm of chromosome 2. The triplicate loci encoding cytosolic TPIs reside on chromosomes 3 and 8. Tpi4 is approximately equidistant (11 cM) from d1 and Lg3, near the centromere of chromosome 3. Tpi3 and Tpi5 are located on distal ends of the most poorly marked maize chromosome; Tpi3 is 29 cM distal to Idh 1 on 8L, and Tpi5 is on 8S or near the centromere on 8L. In contrast to most duplicated maize sequences, which often occur in parallel linkages on different chromosomes, Tpi3 and Tpi5 provide an example of intrachromosomal gene duplication. Several of the Tpi loci are located in sparsely mapped regions of the genome, and Tpi1 is the first isozyme marker for chromosome 7.

Alleles↗
PubMed1996

Phylogenetic analysis of carbamoylphosphate synthetase genes: complex evolutionary history includes an internal duplication within a gene which can root the tree of life.

Carbamoylphosphate synthetase (CPS) catalyzes the first committed step in pyrimidine biosynthesis, arginine biosynthesis, or the urea cycle. Organisms may contain either one generalized or two specific CPS enzymes, and these enzymes may be heterodimeric (encoded by linked or unlinked genes), monomeric, or part of a multifunctional protein. In order to help elucidate the evolution of CPS, we have performed a comprehensive phylogenetic analysis using the 21 available complete CPS sequences, including a sequence from Sulfolobus solfataricus P2 which we report in this paper. This is the first report of a complete CPS gene sequence from an archaeon, and sequence analysis suggests that it encodes an enzyme similar to heterodimeric CPSII. We confirm that internal similarity within the synthetase domain of CPS is the result of an ancient gene duplication that preceded the divergence of the Bacteria, Archaea, and Eukarya, and use this internal duplication in phylogenetic tree construction to root the tree of life. Our analysis indicates with high confidence that this archaeal sequence is more closely related to those of Eukarya than to those of Bacteria. In addition to this ancient duplication which created the synthetase domain, our phylogenetic analysis reveals a complex history of further gene duplications, fusions, and other events which have played an integral part in the evolution of CPS.

Amino Acid Sequence↗
PubMed1997

Phylogenetic reconstruction of vertebrate Hox cluster duplications.

In vertebrates and the cephalochordate, amphioxus, the closest vertebrate relative, Hox genes are linked in a single cluster. Accompanying the emergence of higher vertebrates, the Hox gene cluster duplicated in either a single step or multiple steps, resulting in the four-cluster state present in teleosts and tetrapods. Mammalian Hox clusters (designated A, B, C, and D) extend over 100 kb and are located on four different chromosomes. Reconstructing the history of the duplications and its relation to vertebrate evolution has been problematic due to the lack of alignable sequence information. In this study, the problem was approached by conducting a statistical analysis of sequences from the fibrillar-type collagens (I, II, III, and IV), genes closely linked to each Hox cluster which likely share the same duplication history as the Hox genes. We find statistical support for the hypothesis that the cluster duplication occurred as multiple distinct events and that the four-cluster situation arose by a three-step sequential process.

Animals↗
PubMed1993

Contrasting evolutionary rates in the duplicate chaperonin genes of Mycobacterium tuberculosis and M. leprae.

A phylogenetic analysis of chaperonin (heat shock protein 60) sequences from prokaryotes and eukaryotes indicated that a single gene duplication event in the common ancestor of Mycobacterium tuberculosis, M. leprae, and Streptomyces albus gave rise to the duplicate chaperonin genes found in these species (designated HSP65 and GroEL in the mycobacterial species). Comparison of rates of synonymous and nonsynonymous nucleotide substitution in different gene regions suggested that the 5' end of the HSP65 gene was homogenized by an ancient recombination event between M. tuberculosis and M. leprae. In S. albus, the two duplicated chaperonin genes have evolved at essentially the same rate. In both M. tuberculosis and M. leprae, however, the GroEL gene has evolved considerably more rapidly at nonsynonymous nucleotide sites than has the HSP65 gene. Because this difference is not seen at synonymous sites, it must be due to a difference in selective constraint on the proteins encoded by the two genes, rather than to a difference in mutation rate. The difference between GroEL and HSP65 is striking in regions containing epitopes recognized by T cells of the vertebrate host; in certain cross-reactive epitopes conserved across all organisms, nonsynonymous sites in GroEL have evolved twice as fast as those in HSP65. It is suggested that these differences are correlated with differences in the way in which the duplicate chaperonins of M. tuberculosis and M. leprae interact with the host immune system.

Amino Acid Sequence↗
PubMed1989

Evolution of legume seed storage proteins--a domain common to legumins and vicilins is duplicated in vicilins.

We examined the primary sequence of canavalin, the major storage protein of jack beans, and found that an ancient sequence duplication accounts for 80% of the amino acid residues. Evidence for such a duplication was also found in the orthologous proteins phaseolin and pea vicilin. This sequence duplication presumably accounts for a structural duplication in the canavalin monomer observed by crystallographic analysis. One copy of this repeat was found in a second storage-protein family, the legumins, where it encompasses almost the entire B-chain of the mature molecule. We propose that the vicilin and legumin families of legume seed proteins evolved from a common precursor, which consisted of one copy of the repeat in the vicilins.

Amino Acid Sequence↗
PubMed1998

Complete digital duplication: a case report and review of ulnar polydactyly.

An unusual case is presented of bilateral, complete digital duplication on the hand of a 9-month-old boy. Radiographic evaluation showed duplication of intact phalanges and metacarpals. Although ulnar polydactyly has been described as one of the most common congenital anomalies of the extremities, it usually manifests itself as a rudimentary skin tag. Ulnar polydactyly can be classified on the basis of genetic, morphologic, and clinical implications. Although polydactyly is reported to occur among approximately 1 in 1000 live births, most of these malformations are rudimentary skin tags. Complete ulnar polydactyly is uncommon; it occurs among approximately 0.014% of all live births. The main goal of surgical treatment of patients with complete-duplication ulnar polydactyly is to establish adequate function. This case report describes the preoperative evaluation and management of complete bilateral duplication of the ulnar digits of the hand.

Fingers↗
PubMed1990

Coumadin-induced gastrointestinal hemorrhage associated with an ileal duplication.

A 31-year-old man had recurrent gastrointestinal hemorrhage after aortic valve replacement and initiation of anticoagulation therapy with coumadin. Radionuclide bleeding scan and subsequent contrast angiogram demonstrated a site of hemorrhage in the distal ileum, and at surgery a 1.8-cm spherical duplication was found. On histologic examination, the duplication was lined with normal ileal mucosa, and near the mouth of the duplication an inflammatory ulceration proved to be the site of hemorrhage. In a young patient with anticoagulation-associated gastrointestinal hemorrhage, alimentary tract duplication should be considered.

Adult↗
PubMed2001

Endoscopic management of a duodenal duplication cyst associated with biliary obstruction in an adult.

Duodenal duplication cysts are distinctly uncommon and most often present in infancy or early childhood. The clinical presentation is generally duodenal obstruction, hemorrhage, or pancreatitis. Duodenal duplication cysts rarely cause biliary obstruction in adults. So far, duodenal duplication cysts have been almost exclusively treated by surgical intervention. This report describes both endoscopic diagnosis and treatment of a large periampullary duodenal duplication cyst associated with biliary obstruction in an adult patient.

Adult↗
PubMed1985

Tubular duplication of the jejunum and ileum lined entirely by gastric mucosa.

A 3-year-old boy who suffered from severe colicky abdominal pain is presented. Laboratory studies, including ultrasound, upper gastrointestinal films, and 99mTc-scan, were interpreted as normal. On exploration of the abdomen a tubular duplication of the small bowel was found. The duplication had a common mesentery with the normal bowel. By meticulous dissection the duplication was resected without interfering with the blood supply of the normal bowel. The entire duplication was found to be covered by gastric mucosa.

Abdomen↗
PubMed1991

Erosion through the posterior gastric wall by a pancreatic pseudocyst secondary to gastric duplication.

Gastric duplications are the rarest form of enteric duplication. They account for about 20% of all gastrointestinal duplications. Delayed and missed diagnosis leads to prolonged morbidity and mortality. We report a case of a child with a gastric duplication cyst in the body of the pancreas, associated with a pancreatic pseudocyst that ultimately eroded into the posterior wall of the stomach.

Humans↗
PubMed2003

A female infant with duplication of chromosome 2q33 to 2q37.3.

We report a 13-month-old female child with a de-novo inverted duplication of chromosome 2q extending from 2q33 to 2q37.3. She had microcephaly and craniofacial dysmorphism compatible with previously reported cases with overlapping duplications of chromosome 2q. Although a facial phenotype for pure partial trisomy 2q3 has been described, some controversy still exists regarding possible band specificity for the facial findings. We consider this child provides further evidence for a recognizable facial appearance associated with duplication of chromosome band 2q33 to 2q37.3. Other clinical features found with duplication for chromosome 2q3 have been variable and we provide a summary of the findings in previously reported cases.

Chromosomes, Human, Pair 2↗
PubMed2003

Is common sheath extravesical reimplantation an effective technique to correct reflux in duplicated collecting systems?

PURPOSE: We evaluate the outcome vesicoureteral reflux (VUR) in duplicated collecting systems compared to single collecting systems corrected using an extravesical detrusorrhaphy approach. MATERIALS AND METHODS: We reviewed the records of 266 patients (422 ureters) treated for VUR using an extravesical approach between 1991 and 2001. Inclusion criteria were primary reflux in single (201 patients, 125 bilateral) or duplicated collecting systems (65, 31 bilateral) in patients not undergoing other concomitant surgery with at least 1 year of postoperative followup. The indication for surgical intervention was unresolved reflux (greater than 4 years) in more than 70% of patients. Postoperative evaluation included a voiding cystourethrogram at 3 months and 12 months if reflux was unresolved at 3 months. Also ultrasound was performed at 6 weeks or earlier if clinically indicated and 12 months. RESULTS: Group 1 (duplicated collecting systems) and group 2 (single collecting systems) were comparable for age, sex distribution and reflux grade distribution. Overall success rate at 3 and 12 months was 94.7% and 98.9% for group 1, and 95.1% and 98.5% for group 2, respectively. The difference in success rate at 3 and 12 months was not statistically significant (p >0.05). Of note in both groups postoperative VUR was contralateral in more than 40% of cases. Postoperative hydronephrosis (Society for Fetal Urology grade 1, 2 or 1 increment in grade from preoperative status) was observed in 5.3% and 7.3% of ureteral units at 6 weeks in groups 1 and 2, respectively (p >0.05). At 12 months less than 1% of ureteral units exhibited low grade residual hydronephrosis. No high grade postoperative hydronephrosis was observed in either group, and there were no intraoperative complications. Postoperative urinary retention occurred in 4.7% and 4% of patients in groups 1 and 2, respectively (p >0.05). CONCLUSIONS: Common sheath extravesical reimplantation is highly effective in treating VUR. The common sheath extravesical reimplantation for duplicated collecting systems is as effective in nonduplicated systems and is associated with minimal perioperative morbidity.

Child↗
PubMed2005

The influence of acetylsalicylic acid intake by healthy volunteers on duplicate PFA-100 measurements.

The PFA-100 device is increasingly used for assessing platelet function. Its use to monitor anti-platelet therapy, like acetylsalicylic acid (ASA), has been described. In most studies single PFA-100 measurements were used. In this study, we evaluate the influence of ASA on duplicate measurements using collagen/epinephrine cartridges. Twelve healthy volunteers received a single dose of 160 mg ASA and 12 other healthy volunteers received 30 mg ASA during 10 days followed by 80 mg ASA during 10 days. PFA-100 measurements were performed in duplicate 1 and 24 h after the final intake of medication. The mean coefficient of variation of duplicate measurements before medication was 8.4% and at least two times higher after the intake of a single dose of 160 mg ASA or 30 mg ASA during 10 days. Per individual, huge differences between duplicate measurements were observed after ASA ingestion. Differences were less pronounced after ingestion of 80 mg ASA during 10 days, because six of 12 volunteers had a maximum PFA-100 value>300 s in both measurements. As a consequence, one should be cautious to use the PFA-100 to monitor ASA therapy in individual patients.

Adult↗
PubMed2004

Unilateral duplicated system: comparative length and function of the kidneys.

OBJECTIVE: The objective of this study was to estimate kidney length and function in patients with unilateral duplex kidney. MATERIALS AND METHODS: Thirteen patients with a unilateral duplicated system were reviewed retrospectively. The length of the kidneys was measured by ultrasound, and the relative function of the kidneys was estimated by renal scan. RESULTS: In all patients, the duplex kidney was the left one. The length of the right kidney on the renal ultrasound growth chart was from -1.5 to +0.4 standard deviations from the mean for age, and the left kidney length was from -0.5 to +4.3 standard deviations from the mean. On renal scans the kidneys with a duplicated system contributed 51 to 67% to total renal function; the contralateral ones, 33 to 49%. CONCLUSIONS: Kidneys with a duplicated system may be larger than their counterparts and they may contribute more to total renal function. When a disparity in length between the 2 kidneys is encountered, 1 of the possibilities that should be taken into account is a unilateral duplicated system.

Child↗
PubMed1994

The evolution of functionally novel proteins after gene duplication.

A widely cited model of the evolution of functionally novel proteins (here called the model of mutation during non-functionality (MDN model)) holds that, after gene duplication, one gene copy is redundant and free to accumulate substitutions at random. By chance, some of these substitutions may suit the protein encoded by such a non-functional gene to a new function, which it can subsequently assume. Several lines of evidence contradict this hypothesis: (i) comparison of expressed duplicate genes from the tetraploid frog Xenopus laevis suggests that such genes are subject to purifying selection and are thus not free to accumulate substitutions at random; (ii) in a number of multi-gene families, there is now evidence that functionally distinct proteins have arisen not as a result of chance fixation of neutral variants but rather as a result of positive Darwinian selection; and (iii) the phenomenon of gene sharing, in which a single gene encodes a protein having two distinct functions, shows that gene duplication is not a necessary prerequisite to the evolution of a new protein function. A model for the evolution of new protein is proposed under which a period of gene sharing ordinarily precedes the evolution of functionally distinct proteins. Gene duplication then allows each daughter gene to specialize for one of the functions of the ancestral gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Evolution↗
PubMed1981

Structure of an experimentally evolved gene duplication encoding ribitol dehydrogenase in a mutant of Klebsiella aerogenes.

We have previously described a system of experimental evolution in which many of the mutants of Klebsiella aerogenes selected for faster growth on xylitol ('evolvants') synthesized elevated levels of ribitol dehydrogenase and have presented genetic evidence implicating gene duplication in the enzyme superproduction in some of the evolvants. Here we describe a physical approach to the screening for gene duplications and subsequent structure determination. Nick-translated, cloned ribitol operon (rbt) DNA was used as a hybridization probe to identify fragments containing rbt operon sequences in restriction digests of total bacterial DNA. Whilst several of the evolvants probably harbour duplications spanning the entire rbt operon, one of the spontaneously arising evolvants (strain A3) was shown to harbour a small (5.8 kilobase pairs) direct DNA repeat which encodes the dehydrogenase (but not the kinase) of the closely linked D-arabitol operon as well as the dehydrogenase (but not the kinase) of the rbt operon. The hybridization data suggest that there are 4 to 5 copies of the repeat arranged contiguously on the chromosome. The genetic instability of strain A3, the rbt fragment hybridization pattern of an A3 segregant and the activities of the pentitol catabolic enzymes in A3 are all consistent with the proposed gene duplication structure.

Base Sequence↗
PubMed2025

Analysis of duplication and possible sub-functionalization of wing gene network components in pea aphids.

A fundamental focus of evolutionary-developmental biology is uncovering the genetic mechanisms responsible for the gain and loss of characters. One approach to this question is to investigate changes in the coordinated expression of a group of genes important for the development of a character of interest (a gene regulatory network). Here we consider the possibility that modifications to the wing gene regulatory network (wGRN), as defined by work primarily done in Drosophila melanogaster, were involved in the evolution of wing dimorphisms of the pea aphid (Acyrthosiphon pisum). We hypothesize that this may have occurred via changes in expression levels or duplication followed by sub-functionalization of wGRN components. To test this, we annotated members of the wGRN in the pea aphid genome and assessed their expression levels in first and third nymphal instars of winged and wingless morphs of males and asexual females. We find that only two of the 32 assessed genes exhibit morph-biased expression. We also find that three wing genes (apterous (ap), warts (wts), and decapentaplegic (dpp)) have undergone gene duplication. In each case, the resulting paralogs show signs of functional divergence, exhibiting either sex-, morph-, or stage-specific expression. Two gene duplicates, wts2 and dpp3, are of particular interest with respect to wing dimorphism, as they exhibit a wingless male-specific isoform and wingless male-biased expression, respectively. These results supplement our understanding of trends in developmental gene network evolution, such as side-stepping pleiotropic constraint via duplication and sub-functionalization, underlying the emergence of novel phenotypes.

dimorphism↗
PubMed2005

Retrotransposon accumulation and satellite amplification mediated by segmental duplication facilitate centromere expansion in rice.

The abundance of repetitive DNA varies greatly across centromeres within an individual or between different organisms. To shed light on the molecular mechanisms of centromere repeat proliferation, we performed structural analysis of LTR-retrotransposons, mostly centromere retrotransposons of rice (CRRs), and phylogenetic analysis of CentO satellite repeats harbored in the core region of the rice chromosome 4 centromere (CEN4). The data obtained demonstrate that the CRRs in the centromeric region we investigated have been enriched more significantly by recent rounds of segmental duplication than by original integration of active elements, suggesting that segmental duplication is an important process for CRR accumulation in the centromeric region. Our results also indicate that segmental duplication of large arrays of satellite repeats is primarily responsible for the amplification of satellite repeats, contributing to rapid reshuffling of CentO satellites. Intercentromere satellite homogenization was revealed by genome-wide comparison of CentO satellite monomers. However, a 10-bp duplication present in nearly half of the CEN4 monomers was found to be completely absent in rice centromere 8 (CEN8), suggesting that CEN4 and CEN8 may represent two different stages in the evolution of rice centromeres. These observations, obtained from the only complex eukaryotic centromeres to have been completely sequenced thus far, depict the evolutionary dynamics of rice centromeres with respect to the nature, timing, and process of centromeric repeat amplification.

Centromere↗