Showing papers on "Karyotype published in 2007"
TL;DR: The concept of genetic balance traces back to the early days of genetics and added or subtractions of single chromosomes to the karyotype produced greater impacts on the phenotype than whole-genome changes (ploidy).
Abstract: The concept of genetic balance traces back to the early days of genetics. Additions or subtractions of single chromosomes to the karyotype (aneuploidy) produced greater impacts on the phenotype than whole-genome changes (ploidy). Studies on changes in gene expression in aneuploid and ploidy series
389 citations
TL;DR: This work discusses how chromosome rearrangements come about, and shows how their analysis can determine the evolutionary relationships of all mammals and their descent from a common ancestor.
Abstract: The chromosome complements (karyotypes) of animals display a great diversity in number and morphology. Against this background, the genomes of all species are remarkably conserved, not only in transcribed sequences, but also in some chromosome-specific non-coding sequences and in gene order. A close examination with chromosome painting shows that this conservation can be resolved into small numbers of large chromosomal segments. Rearrangement of these segments into different combinations explains much of the observed diversity in species karyotypes. Here we discuss how these rearrangements come about, and show how their analysis can determine the evolutionary relationships of all mammals and their descent from a common ancestor.
279 citations
TL;DR: Children and adolescents with ALL and hypodiploidy with fewer than 44 chromosomes have a poor outcome despite contemporary therapy, and the presence of a dicentric chromosome, monosomy 7, or both predicted a worse EFS but similar OS.
238 citations
TL;DR: Speculating as to the reasons for the strange behaviour of these chromosomes as well as the role of telomeres and nuclear organisation in avian evolution is suggested.
Abstract: Birds are characterised by feathers, flight, a small genome and a very distinctive karyotype Despite the large numbers of chromosomes, the diploid count of 2n ≈ 80 has remained remarkably constant wi
228 citations
TL;DR: Two modes of chromosome evolution are found in the salmonids: in the Coregoninae and the Salmoninae the chromosomes have evolved by centric fusions of the Robertsonian type decreasing chromosome numbers (2n) while retaining chromosome arm numbers (NF) close to that finding in the hypothetical tetraploid ancestor so that most extant taxa have either type A or type B karyotypes.
Abstract: The karyotypes of salmonid fishes including taxa in the three subfamilies Coregoninae, Thymallinae and Salmoninae are described. This review is an update of the (Hartley, 1987) review of the chromosomes of salmonid fishes. As described in the previous review, the karyotypes of salmonid fishes fall into two main categories based on chromosome numbers: the type A karyotypes have diploid numbers close to 80 with approximately 100 chromosome arms (2n = 80, NF = 100), and the type B karyotypes have diploid numbers close to 60 with approximately 100 chromosome arms (2n = 60, NF = 100). In this paper we have proposed additional sub categories based on variation in the number of chromosome arms: the A' type with NF = 110-120, the A" type with NF greater than 140, and the B' type with NF less than 80. Two modes of chromosome evolution are found in the salmonids: in the Coregoninae and the Salmoninae the chromosomes have evolved by centric fusions of the Robertsonian type decreasing chromosome numbers (2n) while retaining chromosome arm numbers (NF) close to that found in the hypothetical tetraploid ancestor so that most extant taxa have either type A or type B karyotypes. In the Thymallinae, the chromosomes have evolved by inversions so that chromosome arm numbers (NF) have increased but chromosome numbers (2n) close to the karyotype of the hypothetical tetraploid ancestor have been retained and all taxa have type A' karyotypes. Most of the taxa with type B karyotypes in the Coregoninae and Salmoninae are members of the genus Oncorhynchus, although at least one example of type B karyotypes is found in all of the other genera. These taxa either have an anadromous life history or are found in specialized lacustrine environments. Selection for increases or decreases in genetic recombination as proposed by Qumsiyeh, 1994 could have been involved in the evolution of chromosome number in salmonid fishes.
212 citations
TL;DR: The sex chromosome system is being exploited in economically important species and special strains have been devised for mass rearing of male-only broods in the silkworm for higher silk production and in pest species for the release of sterile males in pest management programs.
Abstract: The speciose insect order Lepidoptera (moths and butterflies) and their closest relatives, Trichoptera (caddis flies), share a female-heterogametic sex chromosome system. Originally a Z/ZZ (female/male) system, it evolved by chromosome rearrangement to a WZ/ZZ (female/male) system in the most species-rich branch of Lepidoptera, a monophyletic group consisting of Ditrysia and Tischeriina, which together comprise more than 98% of all species. Further sporadic rearrangements created multi-sex chromosome systems; sporadic losses of the W changed the system formally back to Z/ZZ in some species. Primary sex determination depends on a Z-counting mechanism in Z/ZZ species, but on a female-determining gene, Fem, in the W chromosome of the silkworm. The molecular mechanism is unknown in both cases. The silkworm shares the last step, dsx, of the hierarchical sex-determining pathway with Drosophila and other insects investigated, but probably not the intermediate steps between the primary signal and dsx. The W chromosome is heterochromatic in most species. It contains few genes and is flooded with interspersed repetitive elements. In interphase nuclei of females it is readily discernible as a heterochromatic body which grows with increasing degree of polyploidy in somatic cells. It is used as a marker for the genetic sex in studies of intersexes and Wolbachia infections. The sex chromosome system is being exploited in economically important species. Special strains have been devised for mass rearing of male-only broods in the silkworm for higher silk production and in pest species for the release of sterile males in pest management programs.
163 citations
TL;DR: A comparative study of platypus and echidna by chromosome painting and comparative gene mapping shows that monotremes have a unique XY sex chromosome system that shares some homology with the avian Z.
Abstract: Background
Sex-determining systems have evolved independently in vertebrates. Placental mammals and marsupials have an XY system, birds have a ZW system. Reptiles and amphibians have different systems, including temperature-dependent sex determination, and XY and ZW systems that differ in origin from birds and placental mammals. Monotremes diverged early in mammalian evolution, just after the mammalian clade diverged from the sauropsid clade. Our previous studies showed that male platypus has five X and five Y chromosomes, no SRY, and DMRT1 on an X chromosome. In order to investigate monotreme sex chromosome evolution, we performed a comparative study of platypus and echidna by chromosome painting and comparative gene mapping.
132 citations
TL;DR: The findings indicate that the Y and X chromosomes share the same ancestral autosome and support the prediction that in a haploid organism essential genes on sex chromosomes are more likely to persist than in a diploid organism.
Abstract: Y chromosomes are different from other chromosomes because of a lack of recombination. Until now, complete sequence information of Y chromosomes has been available only for some primates, although considerable information is available for other organisms, e.g., several species of Drosophila. Here, we report the gene organization of the Y chromosome in the dioecious liverwort Marchantia polymorpha and provide a detailed view of a Y chromosome in a haploid organism. On the 10-Mb Y chromosome, 64 genes are identified, 14 of which are detected only in the male genome and are expressed in reproductive organs but not in vegetative thalli, suggesting their participation in male reproductive functions. Another 40 genes on the Y chromosome are expressed in thalli and male sexual organs. At least six of these genes have diverged X-linked counterparts that are in turn expressed in thalli and sexual organs in female plants, suggesting that these X- and Y-linked genes have essential cellular functions. These findings indicate that the Y and X chromosomes share the same ancestral autosome and support the prediction that in a haploid organism essential genes on sex chromosomes are more likely to persist than in a diploid organism.
127 citations
TL;DR: The absence of homology between the bird Z chromosome and the snake and turtle Z sex chromosomes suggests that the origin of the sex chromosomes and the causative genes of sex determination are different between birds and reptiles.
Abstract: Recent progress of chicken genome projects has revealed that bird ZW and mammalian XY sex chromosomes were derived from different autosomal pairs of the common ancestor; however, the evolutionary relationship between bird and reptilian sex chromosomes is still unclear. The Chinese soft-shelled turtle (Pelodiscus sinensis) exhibits genetic sex determination, but no distinguishable (heteromorphic) sex chromosomes have been identified. In order to investigate this further, we performed molecular cytogenetic analyses of this species, and thereby identified ZZ/ZW-type micro-sex chromosomes. In addition, we cloned reptile homologues of chicken Z-linked genes from three reptilian species, the Chinese soft-shelled turtle and the Japanese four-striped rat snake (Elaphe quadrivirgata), which have heteromorphic sex chromosomes, and the Siam crocodile (Crocodylus siamensis), which exhibits temperature-dependent sex determination and lacks sex chromosomes. We then mapped them to chromosomes of each species using FISH. The linkage of the genes has been highly conserved in all species: the chicken Z chromosome corresponded to the turtle chromosome 6q, snake chromosome 2p and crocodile chromosome 3. The order of the genes was identical among the three species. The absence of homology between the bird Z chromosome and the snake and turtle Z sex chromosomes suggests that the origin of the sex chromosomes and the causative genes of sex determination are different between birds and reptiles.
120 citations
TL;DR: The unusual mode of gene regulation in Candida albicans implies that genes in this organism are distributed nonrandomly over chromosomes.
Abstract: Candida albicans maintains genetic diversity by random chromosome alterations, and this diversity allows utilization of various nutrients. Although the alterations seem to occur spontaneously, their frequencies clearly depend on environmental factors. In addition, this microorganism survives in adverse environments, which cause lethality or inhibit growth, by altering specific chromosomes. A reversible loss or gain of one homolog of a specific chromosome in this diploid organism was found to be a prevalent means of adaptation. We found that loss of an entire chromosome is required because it carries multiple functionally redundant negative regulatory genes. The unusual mode of gene regulation in Candida albicans implies that genes in this organism are distributed nonrandomly over chromosomes.
104 citations
TL;DR: An unexpected plethora of chromosome forms, pairing behavior, and hybrid composition in all apomictic lines is revealed, and it is proposed that the Het chromosome plays a role in the genetic control of apomixis.
Abstract: We conducted a cytogenetic study of sexual lines of Boechera stricta and Boechera holboellii (2n = 14) and seven diploid apomictic accessions of their interspecific hybrid Boechera divaricarpa and B. holboellii (2n = 14 or 15). By studying chromosome morphology, rDNA repeats, genome painting, male meiosis, pollen morphology, and flow-cytometry seed screens, we revealed an unexpected plethora of chromosome forms, pairing behavior, and hybrid composition in all apomictic lines. Genome painting demonstrated that the apomicts are alloploid with variable numbers of B. stricta and B. holboellii-like chromosomes. We assume that large-scale homeologous chromosome substitutions took place in the apomictic hybrids that resulted from recurrent diploid–polyploid transitions through restitutional meiosis and polyploidy–diploid transitions through reductional meiosis. A second peculiarity was the presence of a largely heterochromatic chromosome (Het) in all apomictic accessions (2n = 14 and 15) and an additional smaller chromosome (Del) in the aneuploids (2n = 15). Both chromosomes share repetitive pericentromere repeats with those from the sexual B. stricta, suggesting that they originated from this species. Pairing and behavior at meiosis I of the Het share features with both Y and B chromosomes and suggest that the Del arose from a translocation event or homeologous recombination between a B. holboellii (or related taxon) and a B. stricta chromosome. Based on its presence exclusively in apomictic accessions, we propose that the Het chromosome plays a role in the genetic control of apomixis.
01 Jan 2007
TL;DR: Postulated derived karyotype traits in peppers are increases in karyotypes length and asymmetry, nuclear DNA and heterochromatin content, and a scheme of possible evolutionary trends in Capsicum with reference to the origin of the cultivated taxa.
Abstract: Capsicum (chili peppers) is a New World genus with five crop species of great economic importance for food and spices. An up-to-date summary of the karyotypic knowledge is presented, including data on classical staining (chromosome number, size and morphology), silver impregnation (number and position of active nucleolar organizing regions), fluorescent chromosome banding (amount, distribution and type of constitutive heterochromatin), nuclear DNA content measurements (genome size), and fluorescent in situ hybridization (physical mapping of telomeric sequences). Reported chromosome numbers for 23 of the 31 recognized species allow us to distinguish two species groups: one with 2n=2~24 (13 species) and another with 2n=Zu=26 (10 species). The 2n=24 species have comparatively symmetrical karyotypes, mostly with 11 metacentric and 1 subtelocentric (submetacentric) pairs. In contrast, the 2~26 taxa exhibit more asymmetrical complements, with more submetacentric (subtelocentric) chromosomes and frequently one telocentric chromosome. Active nucleolar organizing regions vary in number from one (several species) to four pairs (C. baccatum). Heterochromatin amounts range from 1.80% (C. annuum) to 38.91% (C. tovarii) of the karyotype length, whilst 1C DNA contents vary from 3.35 pg (C. chacoense) to 5.77 pg (C. parvifolium). GC-rich heterochromatin is universal in the genus; AT-rich heterochromatin appears in C. pubescens, C. pereirae and C. campylopodium. The latter species also exhibits mixed GC- and AT-rich heterochromatin. Lack of telomeric sequences in ectopic localizations in the 2n=24 species supports the hypothesis that x=13 has been derived from x=12. Results of chromosome differentiation are compared with molecular data, and a scheme of possible evolutionary trends in Capsicum with reference to the origin of the cultivated taxa is presented. Postulated derived karyotype traits in peppers are increases in karyotype length and asymmetry, nuclear DNA and heterochromatin content. Capsicum chacoense appears as the most primitive taxon while the Brazilian species with 2n=26 seem to be the most advanced, especially C campylopodium. The 2n=26 species form two subgroups according to geographical
TL;DR: The results indicate that nonrandom breakage and rejoining of preferentially gene-dense chromosomes or chromosome segments may have occurred during evolution.
Abstract: Several studies demonstrated a gene-density-correlated radial organization of chromosome territories (CTs) in spherically shaped nuclei of human lymphocytes or lymphoblastoid cells, while CT arrangements in flat-ellipsoidal nuclei of human fibroblasts are affected by both gene density and chromosome size. In the present study, we performed fluorescence in situ hybridization (FISH) experiments to three-dimensionally preserved nuclei (3D-FISH) from human and nonhuman primate cultured lymphoblastoid cells and fibroblasts. We investigated apes, Old, and New World monkeys showing either evolutionarily conserved karyotypes, multiple translocations, fusions, or serial fissions. Our goal was to test whether cell type specific differences of higher order chromatin arrangements are evolutionarily conserved in different primate lineages. Whole genome painting experiments and further detailed analyses of individual chromosomes indicate a gene-density-correlated higher order organization of chromatin in lymphoblastoid cell nuclei of all studied primate species, despite evolutionary chromosome reshuffling. In contrast, in primate fibroblast nuclei evolutionary translocations, fissions and fusions resulted in positional shifts of orthologous chromosome segments, thus arguing against a functional role of chromosome size-dependent spatial chromatin arrangements and for geometrical constraints in flat-ellipsoidal fibroblast nuclei. Notably, in both cell types, regions of rearranged chromosomes with distinct differences in gene density showed polarized arrangements with the more gene-dense segment oriented towards the nuclear interior. Our results indicate that nonrandom breakage and rejoining of preferentially gene-dense chromosomes or chromosome segments may have occurred during evolution.
TL;DR: The parental origin of the missing short arm of the X chromosome has an impact on overweight, kidney, eye, and lipids, which suggests a potential effect of an as-yet-undetermined X chromosome gene imprinting.
Abstract: Context: The phenotype in Turner syndrome (TS) is variable, even in patients with a supposedly nonmosaic karyotype. Previous work suggested that there were X-linked parent-of-origin effects on the phenotype. Hypothesis: The TS phenotype is influenced by the parental origin of the missed X chromosome. Design: This was a multicenter prospective study of TS patients and both their parents, determining parental origin of the X-chromosome, and characterizing the clinical phenotype. Patients and Methods: Eighty-three TS patients and their parents were studied. Inclusion criteria were TS with karyotype 45,X or 46Xi(Xq). Four highly polymorphic microsatellite markers on the X-chromosome DMD49, DYSII, DXS1283, and the androgen receptor gene and three Y chromosome markers, SRY, DYZ1, and DYZ3. Outcome Measures: The study determined the correlation between the parental origin of the X chromosome and the unique phenotypic traits of TS including congenital malformations, anthropometry and growth pattern, skeletal defe...
TL;DR: A Cetartiodactyla ancestral karyotype is proposed and a genome-wide comparative chromosome map of human/pig/cattle is constructed to facilitate the positional cloning of genes by aiding the cross-species transfer of mapping information.
Abstract: The great karyotypic differences between camel, cattle and pig, three important domestic animals, have been a challenge for comparative cytogenetic studies based on conventional cytogenetic approaches. To construct a genome-wide comparative chromosome map among these artiodactyls, we made a set of chromosome painting probes from the dromedary camel (Camelus dromedarius) by flow sorting and degenerate oligonucleotide primed-PCR. The painting probes were first used to characterize the karyotypes of the dromedary camel (C. dromedarius), the Bactrian camel (C. bactrianus), the guanaco (Lama guanicoe), the alpaca (L. pacos) and dromedary × guanaco hybrid karyotypes (all with 2n = 74). These FISH experiments enabled the establishment of a high-resolution GTG-banded karyotype, together with chromosome nomenclature and idiogram for C. dromedarius, and revealed that these camelid species have almost identical karyotypes, with only slight variations in the amount and distribution patterns of heterochromatin. Further cross-species chromosome painting between camel, cattle, pig and human with painting probes from the camel and human led to the establishment of genome-wide comparative maps. Between human and camel, pig and camel, and cattle and camel 47, 53 and 53 autosomal conserved segments were detected, respectively. Integrated analysis with previously published comparative maps of human/pig/cattle enabled us to propose a Cetartiodactyla ancestral karyotype and to discuss the early karyotype evolution of Cetartiodactyla. Furthermore, these maps will facilitate the positional cloning of genes by aiding the cross-species transfer of mapping information.
Ohio State University1, St. Jude Children's Research Hospital2, University of Nebraska Medical Center3, Children's Hospital of Philadelphia4, Children's Mercy Hospital5, Children's Hospital Los Angeles6, University of Minnesota7, Oregon Health & Science University8, Anschutz Medical Campus9, University of Iowa10, Wake Forest University11, University of Mississippi Medical Center12, University of North Carolina at Chapel Hill13, University of Michigan14, University of Texas Southwestern Medical Center15, University of Florida16, University of Nebraska Omaha17, All Children's Hospital18, Medical College of Wisconsin19, American College of Medical Genetics20, University of Alabama at Birmingham21
TL;DR: The results suggest that the abnormal mitosis involves specific chromosomes dependent on the number of chromosomes aberrantly distributed, raising provocative questions regarding the mitotic mechanism.
Abstract: Children with acute lymphoblastic leukemia (ALL) and high hyperdiploidy (>50 chromosomes) are considered to have a relatively good prognosis. The specific extra chromosomes are not random; extra copies of some chromosomes occur more frequently than those of others. We examined the extra chromosomes present in high hyperdiploid ALL to determine if there were a relation of the specific extra chromosomes and modal number (MN) and if the extra chromosomes present could differentiate high hyperdiploid from near-triploid and near-tetraploid cases. Karyotypes of 2,339 children with ALL and high hyperdiploidy at diagnosis showed a distinct nonrandom sequential pattern of gain for each chromosome as MN increased, with four groups of gain: chromosomes 21, X, 14, 6, 18, 4, 17, and 10 at MN 51-54; chromosomes 8, 5, 11, and 12 at MN 57-60; chromosomes 2, 3, 9,16, and 22 at MN 63-67; chromosomes 1, 7 13, 15, 19, and 20 at MN 68-79, and Y only at MN >or=80. Chromosomes gained at lower MN were retained as the MN increased. High hyperdiploid pediatric ALL results from a single abnormal mitotic division. Our results suggest that the abnormal mitosis involves specific chromosomes dependent on the number of chromosomes aberrantly distributed, raising provocative questions regarding the mitotic mechanism. The patterns of frequencies of tetrasomy of specific chromosomes differs from that of trisomies with the exception of chromosome 21, which is tetrasomic in a high frequency of cases at all MN. These results are consistent with different origins of high hyperdiploidy, near-trisomy, and near-tetrasomy.
TL;DR: In this study, repeat-free portions of sequences that were anchored to particular chromosomes including genes, gene clusters, large cDNAs, and portions of BACs obtained from public databases were used to label the corresponding physical location using FISH.
Abstract: Combined with a system for identifying each of the chromosomes in a genome, visualizing the location of individual genetic loci by fluorescence in situ hybridization (FISH) would aid in assembling physical and genetic maps. Previously, large genomic clones have been successfully used as FISH probes onto somatic chromosomes but this approach is complicated in species with abundant repetitive elements. In this study, repeat-free portions of sequences that were anchored to particular chromosomes including genes, gene clusters, large cDNAs, and portions of BACs obtained from public databases were used to label the corresponding physical location using FISH. A collection of probes that includes at least one marker on each chromosome in the maize complement was assembled, allowing a small-target karyotyping system to be developed. This set provides the foundation onto which additional loci could be added to strengthen further the ability to perform chromosomal identification in maize and its relatives. The probes were demonstrated to produce signals in several wild relatives of maize, including Zea luxurians, Z. diploperennis, and Tripsacum dactyloides.
TL;DR: Correlation with clinical features revealed that lipomas with rings/giant markers were larger, occurred in older patients, were more often deep‐seated, and seemed to have an increased tendency to recur locally, compared with tumors with other chromosome aberrations.
Abstract: Conventional lipomas harbor karyotypic changes that could be subdivided into four, usually mutually exclusive, categories: rearrangement, in particular through translocations, of chromosome bands 12q13-15, resulting in deregulation of the HMGA2 gene, loss of material from or rearrangement of chromosome 13, supernumerary ring or giant marker chromosomes, and aberrations of chromosome band 6p21. In the present study, 272 conventional lipomas, two-thirds of them deep-seated, with acquired clonal chromosome changes were assessed with regard to karyotypic and clinical features. A nonrandom distribution of breakpoints and imbalances could be confirmed, with 83% of the cases harboring one or more of the previously known cytogenetic hallmarks. Correlation with clinical features revealed that lipomas with rings/giant markers were larger, occurred in older patients, were more often deep-seated, and seemed to have an increased tendency to recur locally, compared with tumors with other chromosome aberrations. The possible involvement of the HMGA2 gene in cases that did not show any of the characteristic cytogenetic changes was further evaluated by locus-specific metaphase fluorescence in situ hybridization (FISH) and RT-PCR, revealing infrequent cryptic disruption of the gene but abundant expression of full length or truncated transcripts. By FISH, we could also show that breakpoints in bands 10q22-23 do not affect the MYST4 gene, whereas breakpoints in 6p21 or 8q11-12 occasionally target the HMGA1 or PLAG1 genes, respectively, also in conventional lipomas.
TL;DR: It is suggested that ring chromosome formation can act as an alternative chromosome rescue next to telomere healing and capture, particularly for acrocentric chromosomes.
Abstract: Ring chromosomes are rare cytogenetic findings and are associated at phenotypic level with mental retardation and congenital abnormalities. Features specific for ring chromosome syndromes often overlap with the features of terminal deletions for the corresponding chromosomes. Here, we report a case of a ring chromosome 14 which was identified by conventional cytogenetics and shown to have a terminal deletion and an additional inverted duplication with a triplication by using large insert clone and oligo array-comparative genomic hybridization (array-CGH), fluorescence in situ hybridization (FISH) and multiplex ligation-dependent probe amplification (MLPA). The combination of an inverted duplication with a terminal deletion in a ring chromosome is of special interest for the described syndromes of chromosome 14. The presented findings might explain partly overlapping clinical features described in terminal deletion, duplication and ring chromosome 14 cases, as these rearrangements can be easily overlooked when performing GTG-banding only. Furthermore, we suggest that ring chromosome formation can act as an alternative chromosome rescue next to telomere healing and capture, particularly for acrocentric chromosomes. To our knowledge, this is the first time an inverted duplication with a terminal deletion in a ring chromosome is identified and characterized using high-resolution molecular karyotyping. Systematic evaluation of ring chromosomes by array-CGH might be especially useful in distinguishing cases with a duplication/deletion from those with a deletion only.
TL;DR: The results suggest that a deletion firstly occurred in the proximal region close to the centromere of the acrocentric proto-W chromosome and advanced toward the distal region, and in E. elegans, the W-specific repeated sequence elements were amplified site-specifically after deletion of a large part of the W chromosome occurred.
Abstract: To clarify the process of avian sex chromosome differentiation in palaeognathous birds, we performed molecular and cytogenetic characterization of W chromosome-specific repetitive DNA sequences for elegant crested tinamou (Eudromia elegans, Tinamiformes) and constructed comparative cytogenetic maps of the Z and W chromosomes with nine chicken Z-linked gene homologues for E. elegans and ostrich (Struthio camelus, Struthioniformes). A novel family of W-specific repetitive sequences isolated from E. elegans was found to be composed of guanine- and cytosine-rich 293-bp elements that were tandemly arrayed in the genome as satellite DNA. No nucleotide sequence homologies were found for the Struthioniformes and neognathous birds. The comparative cytogenetic maps of the Z and W chromosomes of E. elegans and S. camelus revealed that there are partial deletions in the proximal regions of the W chromosomes in the two species, and the W chromosome is more differentiated in E. elegans than in S. camelus. These results suggest that a deletion firstly occurred in the proximal region close to the centromere of the acrocentric proto-W chromosome and advanced toward the distal region. In E. elegans, the W-specific repeated sequence elements were amplified site-specifically after deletion of a large part of the W chromosome occurred.
TL;DR: The aim of this study was to define the transcriptional changes in trisomy 13, 18, and 21 during early fetal development in order to obtain more insights into the molecular etiopathology of aneuploidy and to support a combination of the two major hypotheses.
Abstract: Among full autosomal trisomies, only trisomies of chromosome 21 (Down syndrome), 18 (Edwards syndrome) and 13 (Patau syndrome) are compatible with postnatal survival. But the mechanisms, how a supernumerary chromosome disrupts the normal development and causes specific phenotypes, are still not fully explained. As an alternative to gene dosage effect due to the trisomic chromosome a genome-wide transcriptional dysregulation has been postulated. The aim of this study was to define the transcriptional changes in trisomy 13, 18, and 21 during early fetal development in order to obtain more insights into the molecular etiopathology of aneuploidy. Using oligonucleotide microarrays, we analyzed whole genome expression profiles in cultured amniocytes (AC) and chorionic villus cells (CV) from pregnancies with a normal karyotype and with trisomies of human chromosomes 13, 18 and 21. We observed a low to moderate up-regulation for a subset of genes of the trisomic chromosomes. Transcriptional levels of most of the genes on the supernumerary chromosome appeared similar to the respective chromosomal pair in normal karyotypes. A subset of chromosome 21 genes including the DSCR1 gene involved in fetal heart development was consistently up-regulated in different prenatal tissues (AC, CV) of trisomy 21 fetuses whereas only minor changes were found for genes of all other chromosomes. In contrast, in trisomy 18 vigorous downstream transcriptional changes were found. Global transcriptome analysis for autosomal trisomies 13, 18, and 21 supported a combination of the two major hypotheses.
TL;DR: In Patients with Swyer syndrome the risk of dysgerminoma is high and gonadectomy is recommended, thus in adolescent with Dysgerminoimas and amenorrhea, karyotype should be done.
Abstract: Dysgerminoma is the most common malignant germ cell tumor of the ovary. This malignancy can be associated with pure gonadal dysgenesis or Swyer syndrome, mixed gonadal dysgenesis and partial gonadal dysgenesis. Dysgerminoma developed in 3 phenotypic female patients with 46 XY pure gonadal dysgenesis. All patients presented first with abdominopelvic mass. Laparatomy was done. 46 XY karyotype was made by lymphocyte culture. Then these patients underwent gonadectomy that histopathology results were streak ovaries without evidence for malignancy. Two patients received postoperative adjuvant therapy. In Patients with Swyer syndrome the risk of dysgerminoma is high and gonadectomy is recommended. Also 5% of dysgerminomas are discovered in phenotypic female and 46 XY karyotype, thus in adolescent with dysgerminoimas and amenorrhea, karyotype should be done.
TL;DR: A 4.3 Mb duplication of chromosome 21 bands q22.13–q22.2 was diagnosed by interphase fluorescent in-situ hybridisation in a 31-week gestational age baby and later found in the mother and in her 8-year-old daughter by the same method and confirmed by array comparative genomic hybridisation (aCGH).
Abstract: A 4.3 Mb duplication of chromosome 21 bands q22.13-q22.2 was diagnosed by interphase fluorescent in-situ hybridisation (FISH) in a 31-week gestational age baby with cystic hygroma and hydrops; the duplication was later found in the mother and in her 8-year-old daughter by the same method and confirmed by array comparative genomic hybridisation (aCGH). All had the facial gestalt of Down syndrome (DS). This is the smallest accurately defined duplication of chromosome 21 reported with a DS phenotype. The duplication encompasses the gene DYRK1 but not DSCR1 or DSCAM, all of which have previously been implicated in the causation of DS. Previous karyotype analysis and telomere screening of the mother, and karyotype analysis and metaphase FISH of a chorionic villus sample, had all failed to reveal the duplication. The findings in this family add to the identification and delineation of a "critical region" for the DS phenotype on chromosome 21. Cryptic chromosomal abnormalities can be missed on a routine karyotype for investigation of abnormal prenatal ultrasound findings, lending support to the use of aCGH analysis in this setting.
TL;DR: In conclusion, chromosome 13 abnormalities and chromosome 1p and/or 1q abnormalities were highly associated, and are risk factors for poor outcome after intensive therapy in multiple myeloma.
Abstract: The prognostic value of chromosomal abnormalities was studied in untreated multiple myeloma patients who were registered into a prospective randomised multicentre phase 3 study for intensified treatment (HOVON24). A total of 453 patients aged less than 66 years with stage II and III A/B disease were registered in the clinical study. Cytogenetic analysis was introduced as a standard diagnostic assay in 1998. It was performed at diagnosis in 160 patients and was successful in 137/160 patients (86%). An abnormal karyotype was observed in 53/137 (39%) of the patients. Abnormalities of chromosome 1p and 1q were found in 19 (36% of patients with an abnormal karyotype) and 21 patients (40%). There was a strong association between chromosome 1p and/or 1q abnormalities and deletion of chromosome 13 or 13q (n = 27, P < 0.001). Patients with karyotypic abnormalities had a significantly shorter overall survival (OS) than patients with normal karyotypes. Complex abnormalities, hypodiploidy, chromosome 1p abnormalities, chromosome 1q abnormalities, and chromosome 13 abnormalities were associated with inferior OS on univariate analysis, as well as after adjustment for other prognostic factors. In conclusion, chromosome 13 abnormalities and chromosome 1p and/or 1q abnormalities were highly associated, and are risk factors for poor outcome after intensive therapy in multiple myeloma.
TL;DR: Using cross-species chromosome painting, a comprehensive comparison of the karyotypes of two Ellobius species with unusual sex determination systems suggests that inversions have played a minor role in the genome evolution of these Ellobia species.
Abstract: Using cross-species chromosome painting, we have carried out a comprehensive comparison of the karyotypes of two Ellobius species with unusual sex determination systems: the Transcaucasian mole vole, Ellobius lutescens (2n = 17, X in both sexes), and the northern mole vole, Ellobius talpinus (2n = 54, XX in both sexes) Both Ellobius species have highly rearranged karyotypes The chromosomal paints from the field vole (Microtus agrestis) detected, in total, 34 and 32 homologous autosomal regions in E lutescens and E talpinus karyotypes, respectively No difference in hybridization pattern of the X paint (as well as Y paint) probes on male and female chromosomes was discovered The set of golden hamster (Mesocricetus auratus) chromosomal painting probes revealed 44 and 43 homologous autosomal regions in E lutescens and E talpinus karyotypes, respectively A comparative chromosome map was established based on the results of cross-species chromosome painting and a hypothetical ancestral Ellobius karyotype was reconstructed A considerable number of rearrangements were detected; 31 and 7 fusion/fission rearrangements differentiated the karyotypes of E lutescens and E talpinus from the ancestral Ellobius karyotype It seems that inversions have played a minor role in the genome evolution of these Ellobius species
TL;DR: A technology using microdissection-based engineering of DNA probes and fluorescence multicolor chromosome banding that allows studying interphase chromosome organization, numbers and rearrangements in somatic cells is introduced.
TL;DR: Analysis of mitotic structures in all five prostate cancer cell lines showed increased frequency of anaphase bridges and nuclear strings, suggesting that despite the expression of telomerase, the reduced telomere length could be driving the observed BFB events and elevated levels of CIN in these lines.
Abstract: Chromosomal instability (CIN) is thought to underlie the generation of chromosomal changes and genomic heterogeneity during prostatic tumorigenesis. The breakage-fusion-bridge (BFB) cycle is one of the CIN mechanisms responsible for characteristic mitotic abnormalities and the occurrence of specific classes of genomic rearrangements. However, there is little detailed information concerning the role of BFB and CIN in generating genomic diversity in prostate cancer. In this study we have used molecular cytogenetic methods and array comparative genomic hybridization analysis (aCGH) of DU145, PC3, LNCaP, 1532T and 1542T to investigate the in vitro role of BFB as a CIN mechanism in karyotype evolution. Analysis of mitotic structures in all five prostate cancer cell lines showed increased frequency of anaphase bridges and nuclear strings. Structurally rearranged dicentric chromosomes were observed in all of the investigated cell lines, and Spectral Karyotyping (SKY) analysis was used to identify the participating rearranged chromosomes. Multicolor banding (mBAND) and aCGH analysis of some of the more complex chromosomal rearrangements and associated amplicons identified inverted duplications, most frequently involving chromosome 8. Chromosomal breakpoint analysis showed there was a higher frequency of rearrangement at centromeric and pericentromeric genomic regions. The distribution of inverted duplications and ladder-like amplifications was mapped by mBAND and by aCGH. Adjacent spacing of focal amplifications and microdeletions were observed, and focal amplification of centromeric and end sequences was present, particularly in the most unstable line DU145. SKY analysis of this line identified chromosome segments fusing with multiple recipient chromosomes (jumping translocations) identifying potential dicentric sources. Telomere free end analysis indicated loss of DNA sequence. Moreover, the cell lines with the shortest telomeres had the most complex karyotypes, suggesting that despite the expression of telomerase, the reduced telomere length could be driving the observed BFB events and elevated levels of CIN in these lines.
TL;DR: It is found that within a single cell, the two nuclei differ both in the number and the size of chromosomes and that representatives of two major genetic groups of G. intestinalis possess different karyotypes.
Abstract: Giardia intestinalis is an ancient protist that causes the most commonly reported human diarrheal disease of parasitic origin worldwide. An intriguing feature of the Giardia cell is the presence of two morphologically similar nuclei, generally considered equivalent, in spite of the fact that their karyotypes are unknown. We found that within a single cell, the two nuclei differ both in the number and the size of chromosomes and that representatives of two major genetic groups of G. intestinalis possess different karyotypes. Odd chromosome numbers indicate aneuploidy of Giardia nuclei, and their stable occurrence is suggestive of a long-term asexuality. A semi-open type of Giardia mitosis excludes a chromosome interfusion between the nuclei. Differences in karyotype and DNA content, and cell cycle-dependent asynchrony are indicative of diversity of the two Giardia nuclei.
TL;DR: The utility of array CGH in the detection and characterization of mosaic marker chromosomes is demonstrated and is anticipated that this will allow detailed characterization of small supernumerary marker chromosomes that will greatly facilitate phenotype/genotype correlations and play a valuable role in the diagnosis and medical management of both pre- and postnatal cases.
TL;DR: 1q/gain MM patients are characterized by complex karyotypes and aggressive disease, and a close association with poor-risk genetic features, such as chromosome 13q deletion and the t(4;14) translocation has also been described.
Abstract: Abnormalities of chromosome 1 are among the most frequent chromosomal alterations in multiple myeloma (MM), being found in up to 45% of patients.1, 2 It has been reported that the short arm of chromosome 1 is preferentially involved in deletions, whereas the long arm is associated with amplification. The gain of 1q (1q/gain) can occur as isochromosomes, duplications or jumping translocations. It has been widely reported that 1q/gain MM patients are characterized by complex karyotypes and aggressive disease, and a close association with poor-risk genetic features, such as chromosome 13q deletion (13) and the t(4;14) translocation has also been described.1 It has been recently demonstrated that gains/amplification of 1q21 increase as the condition goes from smoldering to overt MM, thus suggesting that these regions contain critical genes for disease progression.2 These findings along with the limited information concerning specific transcriptional profiles prompted us to molecularly characterize 1q/gain MMs by FISH and microarray analyses.