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Double partial monosomies (10p- and Xp-) in a female baby with choanal atresia.

Chromosomal abnormalities involving double partial monosomies are very rare. A female infant with non-mosaic monosomy 10p13-->10pter along with monosomy Xp11.4-->Xpter which arose de novo is described. The clinical manifestations of this patient included microcephaly, mild synophrys, short and down-slanted palpebral fissures, ptosis of the left eye, long eyelashes, a depressed nasal bridge, dysplastic ears, micrognathia, a short neck. sensorineural hearing impairment, and severe growth retardation. Left choanal atresia and laryngomalacia were detected by flexible fibroscopy. No signs of hypoparathyroidism or defective cellular immunity could be found. Fluorescence in situ hybridization (FISH) with whole-chromosome painting probes for chromosomes 10 and X was performed, which excluded the possibility of cryptic translocations of the involved chromosome segments. No submicroscopic chromosome 22q11 deletion could be found by FISH. Thus this very rare coexistence of double independent partial monosomies was confirmed. There are no previous reports of such concurrent double partial monosomies.

Choanal Atresia↗

Chromosome pairing in tetraploid rye with monosomic-substitution wheat chromosomes.

In tetraploid rye with single-substitution wheat chromosomes - 1A, 2A, 5A, 6A, 7A, 3B, 5B, 7B - chromosome pairing was analysed at metaphase I in PMCs with the C-banding method. The frequency of univalents of chromosome 1A was considerably higher than that of the other four wheat chromosomes of genome A (6A, 5A, 7A and 2A). Among chromosomes of genome B, the lowest mean frequency of univalents was observed for chromosome 5B. In monosomic lines, wheat chromosomes 1A, 2A, 5A, 6A, 7A and 5B paired with rye homoeologues most often in rod bivalents and in chain quadrivalents (also including 3B). The 47% pairing of 5B-5R chromosomes indicate that the rye genomes block the suppressor Ph1 gene activity. In monosomic plants with chromosomes 5A, 2A, 6A, 7A and 5B, a low frequency of rye univalents was observed. It was also found that the wheat chromosomes influenced the pairing of rye genome chromosomes, as well as the frequency of ring and rod bivalents and tri- and quadrivalents. However, the highest number of terminal chiasmata per chromosome occurred in the presence of chromosomes 5A and 2A, and the lowest - in the presence of chromosomes 3B and 7B. In the presence of chromosome 5B, the highest frequency of bivalents was observed. The results of the present study show that the rye genome is closer related to the wheat genome A of than to genome B. The high pairing of wheat-rye chromosomes, which occurs in tetraploid rye with substitution wheat chromosomes, indicates that there is a high probability of incorporating wheat chromosome segments into rye chromosomes.

Chromosome Banding↗

The 5S rRNA gene clusters have a defined orientation toward the nucleolus in Petunia hybrida and Crepis capillaris.

The 3D localization of the 5S ribosomal RNA genes was studied in cells of the cortex zone of roots in the plant species Petunia hybrida inbred line V26 and in Crepis capillaris. The analysis was carried out on interphase nuclei (both species) and on prophase nuclei (C. capillaris). The 5S ribosomal RNA genes were detected by fluorescence in-situ hybridization and 3D images were obtained by confocal scanning laser microscopy. In both plant species, the 5S ribosomal genes were localized at the short arm of chromosome 2, which, in both plants, also possesses a satellite at its end. Statistical and visual analysis of interphase nuclei showed that: (1) there is a preference for an association of the 5S rRNA gene clusters of the two homologous chromosomes, and (2) the 5S rRNA gene clusters in both species had a preserved spatial position within the interphase nucleus and they tended to be polarized with respect to their neighbouring cells (i.e. a relic telophase orientation). Moreover, tracing of the chromosomal segment between the 5S loci and the active NOR revealed that the homologous chromosomes during early/mid prophase were aligned and that they entered the nucleolus side by side, at least for these chromosome segments. We interpret our data to mean that location of 5S rRNA near the nucleolus favours their functioning in ribosome biogenesis.

Asteraceae↗

The pattern of phylogenomic evolution of the Canidae.

Canidae species fall into two categories with respect to their chromosome composition: those with high numbered largely acrocentric karyotypes and others with a low numbered principally metacentric karyotype. Those species with low numbered metacentric karyotypes are derived from multiple independent fusions of chromosome segments found as acrocentric chromosomes in the high numbered species. Extensive chromosome homology is apparent among acrocentric chromosome arms within Canidae species; however, little chromosome arm homology exists between Canidae species and those from other Carnivore families. Here we use Zoo-FISH (fluorescent in situ hybridization, also called chromosomal painting) probes from flow-sorted chromosomes of the Japanese raccoon dog (Nyctereutes procyonoides) to examine two phylogenetically divergent canids, the arctic fox (Alopex lagopus) and the crab-eating fox (Cerdocyon thous). The results affirm intra-canid chromosome homologies, also implicated by G-banding. In addition, painting probes from domestic cat (Felis catus), representative of the ancestral carnivore karyotype (ACK), and giant panda (Ailuropoda melanoleuca) were used to define primitive homologous segments apparent between canids and other carnivore families. Canid chromosomes seem unique among carnivores in that many canid chromosome arms are mosaics of two to four homology segments of the ACK chromosome arms. The mosaic pattern apparently preceded the divergence of modern canid species since conserved homology segments among different canid species are common, even though those segments are rearranged relative to the ancestral carnivore genome arrangement. The results indicate an ancestral episode of extensive centric fission leading to an ancestral canid genome organization that was subsequently reorganized by multiple chromosome fusion events in some but not all Canidae lineages.

Animals↗

Chromosomal location of three spectrin genes: relationship to the inherited hemolytic anemias of mouse and man.

Three genetic loci in the mouse affect the synthesis and assembly of the erythrocyte membrane skeleton. The spherocytosis and jaundiced loci affect the membrane skeletal protein known as spectrin. The normoblastosis locus affects the spectrin binding protein called ankyrin. We have obtained genetic data that define the linkage relationships among three spectrin genes and the spherocytosis and jaundiced loci. The erythroid alpha-spectrin gene is tightly linked to the spherocytosis locus on chromosome 1 and the jaundiced locus is on chromosome 12, tightly linked to the erythroid beta-spectrin gene. The brain alpha-spectrin (alpha-fodrin) gene is located on the centromeric end of chromosome 2 and is not closely linked to any previously mapped erythroid or neurological mutation. These results are consistent with the hypothesis that defects in the alpha- and beta-spectrin genes cause the spherocytosis and jaundiced hemolytic anemias in mice. All five loci studied are located within chromosomal segments that are conserved between mouse and man. Analysis of the data from the chromosome 12 study defines a new order for the genes on that chromosome and delineates the largest mouse/human conserved chromosomal segment yet known.

Anemia, Hemolytic↗

Genetic analysis of "metabolic syndrome" in the spontaneously hypertensive rat.

In the current review, we summarize results of genetic analyses of "metabolic syndrome" in the spontaneously hypertensive rat (SHR). These results include (1) linkage analyses in the HXB/BXH recombinant inbred (RI) strains derived from SHR and Brown Norway (BN-Lx) strains which revealed quantitative trait loci (QTL) for hemodynamic and metabolic traits on several chromosomes, (2) genetic isolation of these putative QTL within differential chromosome segments of SHR.BN congenic strains, (3) detailed mapping of these QTL within limited chromosome segments of SHR.BN congenic sublines, (4) sequencing of selected positional candidate genes which revealed important mutations in the Cd36 and Srebp1 SHR genes, (5) functional tests of these candidate genes in SHR transgenic lines, and (6) integrated gene expression profiling and linkage mapping in RI strains which will be used to identify co-regulated genes and to determine co-segregation of transcriptional profiles with physiological and pathophysiological phenotypes.

Animals↗

Temporal profile of replication of human chromosomes.

Chromosomes in human cancer cells are expected to initiate replication from predictably localized origins, firing reproducibly at discrete times in S phase. Replication products obtained from HeLa cells at different stages of S phase were hybridized to cDNA and genome tiling oligonucleotide microarrays to determine the temporal profile of replication of human chromosomes on a genome-wide scale. About 1,000 genes and chromosomal segments were identified as sites containing efficient origins that fire reproducibly. Early replication was correlated with high gene density. An acute transition of gene density from early to late replicating areas suggests that discrete chromatin states dictate early versus late replication. Surprisingly, at least 60% of the interrogated chromosomal segments replicate equally in all quarters of S phase, suggesting that large stretches of chromosomes are replicated by inefficient, variably located and asynchronous origins and forks, producing a pan-S phase pattern of replication. Thus, at least for aneuploid cancer cells, a typical discrete time of replication in S phase is not seen for large segments of the chromosomes.

Chromosomes, Human↗

EBL-1, a putative erythrocyte binding protein of Plasmodium falciparum, maps within a favored linkage group in two genetic crosses.

The Duffy binding-like (DBL) superfamily of Plasmodium falciparum encompasses genes which encode ligands for host cell receptors. This superfamily includes two distinct groups of genes, the var genes which encode antigenically variant cytoadherence proteins (PfEMP1), and the eba-175 gene which encodes a glycophorin A binding protein involved in erythrocyte invasion. Here we describe another DBL superfamily member related to eba-175, the ebl-1 gene. Like the eba-175 gene, ebl-1 is a single copy gene encoding DBL domains that have sequences and an overall arrangement distinct from var genes. The inheritance of ebl-1 was found to be strongly favored in two genetic crosses in which one parental clone lacked a chromosome segment carrying the gene. A proliferation phenotype has been previously linked to the same chromosome segment in the first genetic cross. These results suggest that ebl-1 and eba-175 are related members of a multigene family involved in the invasion of erythrocytes by P. falciparum.

Amino Acid Sequence↗

[Phenotype and "critical segments" of chromosomes during partial aneuploidy for chromosome 4 in man].

Computerized analysis of sparse matrix, based on the list of involved organs, body parts, extremities, function etc. (total item number about 600) was performed for different cytogenetically identified anomalies of human chromosome 4 (35 cases of 4p-, 32 cases of 4p+, 39 cases of 4q-, 39 cases of 4q+; both published and original data were used). For each of the four types of partial aneusomy, 4 specific enough groups of traits were revealed which had been found in 50% of respective patients, at least. Such "nuclei" of traits were highly similar to those given in comprehensive modern manuals. However, 4p- and 4q- could only be classified as strictly enough delineated chromosomal syndromes. The 4(p14-pter) region was found to be the most likely crucial segment for the Wolf-Hirschhorn syndrome.

Aneuploidy↗

Comparative molecular cytogenetic studies in the order Carnivora: mapping chromosomal rearrangements onto the phylogenetic tree.

We have made a set of chromosome-specific painting probes for the American mink by degenerate oligonucleotide primed-PCR (DOP-PCR) amplification of flow-sorted chromosomes. The painting probes were used to delimit homologous chromosomal segments among human, red fox, dog, cat and eight species of the family Mustelidae, including the European mink, steppe and forest polecats, least weasel, mountain weasel, Japanese sable, striped polecat, and badger. Based on the results of chromosome painting and G-banding, comparative maps between these species have been established. The integrated map demonstrates a high level of karyotype conservation among mustelid species. Comparative analysis of the conserved chromosomal segments among mustelids and outgroup species revealed 18 putative ancestral autosomal segments that probably represent the ancestral chromosomes, or chromosome arms, in the karyotype of the most recent ancestor of the family Mustelidae. The proposed 2n = 38 ancestral Mustelidae karyotype appears to have been retained in some modern mustelids, e.g., Martes, Lutra, Ictonyx, and Vormela. The derivation of the mustelid karyotypes from the putative ancestral state resulted from centric fusions, fissions, the addition of heterochromatic arms, and occasional pericentric inversions. Our results confirm many of the evolutionary conclusions suggested by other data and strengthen the topology of the carnivore phylogenetic tree through the inclusion of genome-wide chromosome rearrangements.

Animals↗

Cytological indications of the complex subtelomeric structure.

Research on the subtelomeric region has considerably increased because this chromosome segment (1) keeps the chromosome number constant, (2) intervenes in cancer and cell senescence processes, (3) presents more crossovers than other regions of the genome and, (4) is the site of cryptic chromosome aberrations associated with mental retardation and congenital malformations. Quantitative microphotometrical scanning and computer graphic image analysis enables the detection of differentially distributed Giemsa-stained structures in T-banded subtelomeric segments of human and Chinese hamster ovary (CHO) chromosomes. The presence of high density stain patterns in the subtelomeric region was confirmed using endoreduplicated chromosomes as a model. Besides, prolonging the incubation in the T-buffer, specific holes were induced in subtelomeric segments. Hole specificity was confirmed inducing them in complex CHO chromosome aberrations obtained by AluI. The method was also used to detect minute sister chromatid exchanges in the T-banded subtelomeric area (t-SCEs). The presence of t-SCEs was suspected to reflect, at the microscope level, the high crossover activity prevailing in the region. Due to the fact that the fluorescent signals obtained with subtelomeric probes seem to be colocalized with subtelomeric high density areas, measurements on the position of both structures with respect to the diffraction and chromosome edges were carried out. Data obtained showed comparable values suggesting that the high density segments were located where telomeric probes usually fluoresce. The possible relationship of the high density patterns, the production of specific holes, the localization of fluorescent areas and the detection of minute SCEs in the subtelomeric segment observed in T-banded CHO and human chromosomes is briefly reviewed.

Animals↗

Intra-chromosomal rearrangements generated by Cre-lox site-specific recombination.

Chromosomal rearrangements are useful genetic and breeding tools but are often difficult to detect and characterize. To more easily identify and define chromosome deletions and inversions, we have used the bacteriophage P1 Cre-lox site-specific recombination system to generate these events in plants. This involves three steps: (i) the introduction of two lox sites into one locus in a plant genome, including one site within a modified Ds transposon; (ii) Ac transposase-mediated transposition of the Ds-lox element to a new locus on the same chromosome; (iii) Cre-mediated site-specific recombination between the two lox sites that bracket a chromosome segment. We report the production of a deletion and three inversion events in tobacco. The utility of chromosomal segments bracketed by lox sites for targeted manipulation and cloning is discussed.

Base Sequence↗

[RFLP analysis on wide compatibility genes in rice variety dular of ecotype aus].

Dular is one of the typical wide compatibility varieties in ecotype Aus of rice. Genetic analysis on wide compatibility genes (WCG) from Dular based on triple crosses (indica//++Dular/japonica) was conducted. In the condition of being shaded for 7 days, the individual spikelet fertility segregated obviously, and the continuous distributions of spikelet fertility with a handful of peaks were observed. This suggested that the segregation of spikelet fertility in triple cross populations was controlled by one or more major genes, also modified by some minor genes. Based on 109 individuals of triple cross Nanjing 11 (indica)//++Dular/2533(japonica, a marker gene line, Rc and g), fertile and semisterile pools were set up by bulked segregant analysis, the RFLP analysis of the two pools led to the discovery of three chromosomal segments co-segregating with fertility. The one is on the interval RG213-C235 on chromosome 6. According to the previous studies, it may be the wide compatibility gene S5n. The other two were on the interval RG901-RG413 and G402-RG651 on chromosome 12, temporarily designated as Sd1(t)n and Sd2(t)n, respectively. Because of the continuous distribution for spikelet fertility, we also used a quantitative model to evaluate the effects of those three loci. On the basis of interval analysis with Mapmaker/QTL, 32.3% of the phenotypic variance associated with spikelet fertility was explained by the S5n (LOD = 9.03), and the other two chromosomal segments were responsible for 10.5%(LOD = 2.61) and 10.9%(LOD = 2.14) phenotypic variance, respectively. The results demonstrated that the wide compatibility variety Dular contained three WCGs. To introgress the three WCGs into a restorer line or an abortive line will overcome the hybrid sterility barrier of indica/japonica crosses, and the precise RFLP mapping will be useful for breeders to accumulate a few genes of interest into one cultivar by means of molecular marker assisted selection.

Chromosome Mapping↗

Chromosome anomalies in mammary carcinoma from transgenic WAPRAS mice: compression with human data.

Transgenic WAPRAS mice, obtained by infection of the construct WAP promoter murine gene and the HRAS human protooncogene, develop mammary adenocarcinoma within 1-3 months after pregnancy. A cytogenetic analysis was performed on 17 tumors from 10 mice. Almost all detected anomalies were chromosome gains. The resulting trisomies affected recurrently chromosomes 1, 15, 19, 17, 7, and 12, in decreasing order of involvement. Although in situ hybridization showed that the transgene was integrated in chromosome 1, the duplication of this chromosome did not depend on the presence or absence of the transgene. Comparison with human data indicates that the 3 most frequently duplicated chromosomes in WAPRAS mice correspond to the human chromosome segments most frequently duplicated or amplified in breast cancer, i.e., 1q, 8q, and 11q13. None of the chromosome segments often deleted in human tumors were found to be duplicated in the mouse tumors.

Adenocarcinoma↗

Genomic constitution and variation in five partial amphiploids of wheat--Thinopyrum intermedium as revealed by GISH, multicolor GISH and seed storage protein analysis.

Genomic in situ hybridization (GISH) and multicolor GISH (mcGISH) methodology were used to establish the cytogenetic constitution of five partial amphiploid lines obtained from wheat x Thinopyrum intermedium hybridizations. Line Zhong 1, 2 n=52, contained 14 chromosomes from each of the wheat genomes plus ten Th. intermedium chromosomes, with one pair of A-genome chromosomes having a Th. intermedium chromosomal segment translocated to the short arm. Line Zhong 2, 2 n=54, had intact ABD wheat genome chromosomes plus 12 Th. intermedium chromosomes. The multicolor GISH results, using different fluorochrome labeled Th. intermedium and the various diploid wheat genomic DNAs as probes, indicated that both Zhong 1 and Zhong 2 contained one pair of Th. intermedium chromosomes with a significant homology to the wheat D genome. High-molecular-weight (HMW) glutenin and gliadin analysis revealed that Zhong 1 and Zhong 2 had identical banding patterns that contained all of the wheat bands and a specific HMW band from Th. intermedium. Zhong 1 and Zhong 2 had good HMW subunits for wheat breeding. Zhong 3 and Zhong 5, both 2 n=56, possessed no gross chromosomal aberrations or translocations that were detectable at the GISH level. Zhong 4 also had a chromosome number of 2 n=56 and contained the complete wheat ABD-genome chromosomes plus 14 Th. intermedium chromosomes, with one pair of Th. intermedium chromosomes being markedly smaller. Multicolor GISH results indicated that Zhong 4 also contained two pairs of reciprocally translocated chromosomes involving the A and D genomes. Zhong 3, Zhong 4 and Zhong 5 contained a specific gliadin band from Th. intermedium. Based on the above data, it was concluded that inter-genomic transfer of chromosomal segments and/or sequence introgression had occurred in these newly synthesized partial amphiploids despite their diploid-like meiotic behavior and disomic inheritance.

Breeding↗

Incomplete trisomy 22. II. Familial trisomy of the distal segment of chromosome 22q in two brothers from a mother with a translocation, t(6;22)(q27;q13).

Two brothers with duplication of the distal segment of 22q inherited from a t(6;22)(q27;13) translocation carrier mother presented with intrauterine growth retardation, congenital hydrocephalus, cleft palate, genital hypoplasia with cryptorchidism and hypospadias, and similar facial features including mongoloid position of eyeaxes, hypertelorism, small nose with prominent bridge, prominent upper lip, and small mandible. In addition the second sib revealed renal hypoplasia, arrhinencephaly and pentalogy of Fallot. The patients died at ages eight days and one day, respectively. The two brothers appear to be the first instances of familial trisomy 22q13 leads to qter.

Chromosomes, Human, 21-22 and Y↗