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PubMed1983

Long-term marrow culture reveals chromosomally normal hematopoietic progenitor cells in patients with Philadelphia chromosome-positive chronic myelogenous leukemia.

We found that when marrow cells from four patients with newly diagnosed Philadelphia chromosome-positive chronic myelogenous leukemia were maintained in culture for two to four weeks, a previously undetectable population of chromosomally normal hematopoietic cells (including erythroid, granulopoietic, and pluripotent progenitors) became readily demonstrable in three cases. Time-course studies showed that in such cultures the dominant Philadelphia chromosome-positive population rapidly disappeared, in contrast to coexisting chromosomally normal progenitors, which remained detectable for periods of two to three months. Long-term marrow cultures thus offer a new approach to the assessment of a suppressed but functionally intact population of chromosomally normal hematopoietic stem cells in patients with chronic myelogenous leukemia.

Adult↗
PubMed2002

A comparative radiation hybrid map of bovine chromosome 18 and homologous chromosomes in human and mice.

A comprehensive radiation hybrid (RH) map and a high resolution comparative map of Bos taurus (BTA) chromosome 18 were constructed, composed of 103 markers and 76 markers, respectively, by using a cattle-hamster somatic hybrid cell panel and a 5,000 rad whole-genome radiation hybrid (WGRH) panel. These maps include 65 new assignments (56 genes, 3 expressed-sequence tags, 6 microsatellites) and integrate 38 markers from the first generation WGRH(5,000) map of BTA18. Fifty-nine assignments of coding sequences were supported by somatic hybrid cell mapping to markers on BTA18. The total length of the comprehensive map was 1666 cR(5,000). Break-point positions within the chromosome were refined and a new telomeric RH linkage group was established. Conserved synteny between cattle, human, and mouse was found for 76 genes of BTA18 and human chromosomes (HSA) 16 and 19 and for 34 cattle genes and mouse chromosomes (MMU) 7 and 8. The new RH map is potentially useful for the identification of candidate genes for economically important traits, contributes to the expansion of the existing BTA18 gene map, and provides new information about the chromosome evolution in cattle, humans, and mice.

Animals↗
PubMed1988

Fluorescence in situ hybridization with human chromosome-specific libraries: detection of trisomy 21 and translocations of chromosome 4.

Chromosomes can be specifically stained in metaphase spreads and interphase nuclei by in situ hybridization with entire chromosome-specific DNA libraries. Unlabeled human genomic DNA is used to inhibit the hybridization of sequences in the library that bind to multiple chromosomes. The target chromosome can be made at least 20 times brighter per unit length than the others. Trisomy 21 and translocations involving chromosome 4 can be detected in metaphase spreads and interphase nuclei by using this technique.

Cells, Cultured↗
PubMed1991

X chromosome-linked and mitochondrial gene control of Leber hereditary optic neuropathy: evidence from segregation analysis for dependence on X chromosome inactivation.

Leber hereditary optic neuropathy (LHON) has been shown to involve mutation(s) of mitochondrial DNA, yet there remain several confusing aspects of its inheritance not explained by mitochondrial inheritance alone, including male predominance, reduced penetrance, and a later age of onset in females. By extending segregation analysis methods to disorders that involve both a mitochondrial and a nuclear gene locus, we show that the available pedigree data for LHON are most consistent with a two-locus disorder, with one responsible gene being mitochondrial and the other nuclear and X chromosome-linked. Furthermore, we have been able to extend the two-locus analytic method and demonstrate that a proportion of affected females are likely heterozygous at the X chromosome-linked locus and are affected due to unfortunate X chromosome inactivation, thus providing an explanation for the later age of onset in females. The estimated penetrance for a heterozygous female is 0.11 +/- 0.02. The calculated frequency of the X chromosome-linked gene for LHON is 0.08. Among affected females, 60% are expected to be heterozygous, and the remainder are expected to be homozygous at the responsible X chromosome-linked locus.

DNA, Mitochondrial↗
PubMed1994

Chromosome painting in plants: in situ hybridization with a DNA probe from a specific microdissected chromosome arm of common wheat.

We report here on the successful painting of a specific plant chromosome within its own genome. Isochromosomes for the long arm of chromosome 5 of the wheat B genome (5BL) were microdissected from first meiotic metaphase spreads of a monoisosomic 5BL line of the common wheat Triticum aestivum cv. Chinese Spring. The dissected isochromosomes were amplified by degenerate oligonucleotide-primed PCR in a single tube reaction. The amplified DNA was used as a complex probe mixture for fluorescent in situ hybridization on first meiotic metaphase spreads of lines carrying 5BL as a distinctive marker. Hybridization signals were observed, specifically, along the entire 5BL. In some of the cells, labeling was also detected in two bivalents, presumably those of the 5B "homoeologues" (partial homologues) found in common wheat (5A and 5D). The probe also revealed discrete domains in tapetal nuclei at interphase, further supporting the probe's high specificity. These data suggest that chromosome and homoeologous group-specific sequences are more abundant in 5BL than genome-specific sequences. Chromosome-painting probes, such as the one described here for 5BL, can facilitate the study of chromosome evolution in polyploid wheat.

Base Sequence↗
PubMed2000

Rapid generation of nested chromosomal deletions on mouse chromosome 2.

Nested chromosomal deletions are powerful genetic tools. They are particularly suited for identifying essential genes in development either directly or by screening induced mutations against a deletion. To apply this approach to the functional analysis of mouse chromosome 2, a strategy for the rapid generation of nested deletions with Cre recombinase was developed and tested. A loxP site was targeted to the Notch1 gene on chromosome 2. A targeted line was cotransfected with a second loxP site and a plasmid for transient expression of Cre. Independent random integrations of the second loxP site onto the targeted chromosome in direct repeat orientation created multiple nested deletions. By virtue of targeting in an F(1) hybrid embryonic stem cell line, F(1)(129S1xCast/Ei), the deletions could be verified and rapidly mapped. Ten deletions fell into seven size classes, with the largest extending six or seven centiMorgans. The cytology of the deletion chromosomes were determined by fluorescent in situ hybridization. Eight deletions were cytologically normal, but the two largest deletions had additional rearrangements. Three deletions, including the largest unrearranged deletion, have been transmitted through the germ line. Several endpoints also have been cloned by plasmid rescue. These experiments illustrate the means to rapidly create and map deletions anywhere in the mouse genome. They also demonstrate an improved method for generating nested deletions in embryonic stem cells.

Animals↗
PubMed2003

Meiotic condensin is required for proper chromosome compaction, SC assembly, and resolution of recombination-dependent chromosome linkages.

Condensin is an evolutionarily conserved protein complex that helps mediate chromosome condensation and segregation in mitotic cells. Here, we show that condensin has two activities that contribute to meiotic chromosome condensation in Saccharomyces cerevisiae. One activity, common to mitosis, helps mediate axial length compaction. A second activity promotes chromosome individualization with the help of Red1 and Hop1, two meiotic specific components of axial elements. Like Red1 and Hop1, condensin is also required for efficient homologue pairing and proper processing of double strand breaks. Consistent with these functional links condensin is necessary for proper chromosomal localization of Red1 and Hop1 and the subsequent assembly of the synaptonemal complex. Finally, condensin has a Red1/Hop1-independent role in the resolution of recombination-dependent linkages between homologues in meiosis I. The existence of distinct meiotic activities of condensin (axial compaction, individualization, and resolution of recombination-dependent links) provides an important framework to understand condensin's role in both meiotic and mitotic chromosome structure and function.

Adenosine Triphosphatases↗
PubMed1969

Chromosome micromanipulation. 3. Spindle fiber tension and the reorientation of mal-oriented chromosomes.

Kinetochore reorientation is the critical process ensuring normal chromosome distribution. Reorientation has been studied in living grasshopper spermatocytes, in which bivalents with both chromosomes oriented to the same pole (unipolar orientation) occur but are unstable: sooner or later one chromosome reorients, the stable, bipolar orientation results, and normal anaphase segregation to opposite poles follows. One possible source of stability in bipolar orientations is the normal spindle forces toward opposite poles, which slightly stretch the bivalent. This tension is lacking in unipolar orientations because all the chromosomal spindle fibers and spindle forces are directed toward one pole. The possible role of tension has been tested directly by micromanipulation of bivalents in unipolar orientation to artificially create the missing tension. Without exception, such bivalents never reorient before the tension is released; a total time "under tension" of over 5 hr has been accumulated in experiments on eight bivalents in eight cells. In control experiments these same bivalents reoriented from a unipolar orientation within 16 min, on the average, in the absence of tension. Controlled reorientation and chromosome segregation can be explained from the results of these and related experiments.

Animals↗
PubMed1989

Change in chromosome number associated with a double deletion in the Neurospora crassa mitochondrial chromosome.

The mitochondrial genome of Neurospora is usually found in a single covalently closed circular 62-kbp DNA molecule. We report here that the mitochondrial genome of a phenotypic revertant of a stopper mutant (stp-ruv) is contained primarily in two separate, nonoverlapping, autonomously replicating circular chromosomes. The circles, one about 21 kbp and the other somewhat less than 36 kbp are derived from the most frequent classes of recombinant chromosomes (21 and 41 kbp) in the chromosomal population of mitochondria in the original stopper mutant. The new, more stable chromosomal configuration, is associated with the deletion of two sequences (1 kbp and 4 kbp) at the splice junctions of the two circles. The data suggest that both deletions are likely to have originated from a single recombinational event involved in generating the 36-kbp circle. Secondary, spontaneously arising derivatives of stp-ruv have been found to yield, at high copy number, short sections of the 21-kbp circle in covalently closed supercoiled circles varying from unit length to very high multimers. The amplified segments span a common segment likely to contain the replication origin of the 21-kbp chromosome.

Chromosome Deletion↗
PubMed1991

Directed synthesis of a segmental chromosomal transposition: an approach to the study of chromosomes lethal to the gametophyte generation of maize.

Because of the haploid nature of the gametophyte generation of plants, most mutations that are lethal or detrimental to the gametophytes cannot be recovered. Our laboratory is currently developing several techniques to overcome this situation. In this paper, a procedure is described to generate directed segmental chromosomal transpositions. The method involves recovery of recombinants between reciprocal translocation overlaps such that one region of the genome is inserted into a nonhomologous chromosome in a predetermined and directed manner. This duplicated segment then could serve to cover deficiencies or mutations, lethal to the gametophytes, in the region from whence it originated. The manipulation of segmental chromosomal transpositions for analyzing mutants lethal or detrimental to the gametophyte generation is discussed. The procedure to generate transpositions, the translocations between normal A and supernumerary B chromosomes that generate deficiencies in the male gametes, the r-X1 chromosome that generates deficiencies in the female gametes and other techniques available in maize form a system to analyze gametophyte lethal mutations.

Alcohol Dehydrogenase↗
PubMed1997

The enigma of Y chromosome degeneration: TRAM, a novel retrotransposon is preferentially located on the Neo-Y chromosome of Drosophila miranda.

We have cloned a novel transposable element from the neo-Y chromosome of Drosophila miranda. The size of the element, designated as TRAM, is 3.452 bp, including on both sides long terminal direct repeats (LTRs) of 372 bp, respectively. The element is flanked by a 5-bp target site duplication, ATATG. The putative primer binding site (PBS) for minus-strand priming is complementary to 18 nucleotides of the 3'-end of tRNA(Trp). Data base screens for DNA sequence identities were negative, apart from the sequence motif of the PBS. The deduced amino acid sequence from the large ORF does not reveal identities described for other transposons. In situ hybridizations with TRAM subclones show a biased distribution in the genome, with a massive accumulation of TRAM in the neo-Y chromosome, while the former homologue, the X2 chromosome is devoid of TRAM sites. The enriched occurrence of the TRAM element at the evolving neo-Y chromosome of D.miranda adds compelling evidence in favor of the view that Y chromosome degeneration is driven by the accumulation of transposable elements.

Animals↗
PubMed1992

Chromosomal abnormalities in patients with Hodgkin's disease: evidence for frequent involvement of the 14q chromosomal region but infrequent bcl-2 gene rearrangement in Reed-Sternberg cells.

BACKGROUND: Rearrangements of the bcl-2 gene (also known as BCL2) have been detected in up to 40% of cases of Hodgkin's disease, and it has been speculated that such rearrangements may have a role in the pathogenesis of Hodgkin's disease. PURPOSE: The purposes of this study were (a) to assess the frequency of clonal chromosomal abnormalities in Hodgkin's disease, (b) to identify recurrent changes, (c) to determine whether the bcl-2 gene rearrangement was present in Reed-Sternberg cells (the neoplastic cells of Hodgkin's disease) and their variants, and (d) to analyze whether the presence of t(14;18) translocations in Reed-Sternberg cells explains the observed bcl-2 gene rearrangements in Hodgkin's disease. METHODS: A cytogenetic study was performed on biopsy specimens from 28 consecutive untreated patients with Hodgkin's disease. The same patients were analyzed for bcl-2 gene rearrangement by a polymerase chain reaction (PCR) technique. To ascertain whether the abnormal karyotypes were present in and restricted to Reed-Sternberg cells, we also performed in situ hybridization with chromosome-specific probes. RESULTS: Abnormal metaphases were identified in 23 of the 28 patients. In 11 patients, the chromosome 14q region was abnormal; in six of these patients, there was involvement of the 14q32 region that comprises the gene encoding for heavy-chain immunoglobulin. Only one patient had a t(14;18) translocation, whereas almost 40% of these 28 patients showed bcl-2 gene rearrangements by a PCR method. The in situ hybridization method showed that the abnormal karyotype was present in and restricted to Reed-Sternberg cells. CONCLUSIONS: We conclude that the majority of cases of Hodgkin's disease contain a clonal population with an abnormal karyotype, comprising the Reed-Sternberg cells. The q32 region of chromosome 14 is frequently involved, but a t(14;18) translocation is extremely infrequent. The occurrence of a bcl-2 gene rearrangement in Hodgkin's disease most likely results from the presence of sporadic, small bystander B lymphocytes that carry the translocation and that also can be frequently detected in reactive lymphoid tissue such as tonsils. Also, a range of different chromosomal translocations may provide growth or survival advantages to Reed-Sternberg cells.

Chromosomes, Human, Pair 14↗
PubMed1985

Chromosome-specific alpha satellite DNA: nucleotide sequence analysis of the 2.0 kilobasepair repeat from the human X chromosome.

The pericentromeric region of the human X chromosome is characterized by a tandemly repeated family of 2.0 kilobasepair (kb) DNA fragments, initially revealed by cleavage of human DNA with the restriction enzyme BamHI. We report here the complete nucleotide sequence of a cloned member of the repeat family and establish that this X-linked DNA family consists entirely of alpha satellite DNA. Our data indicate that the 2.0 kb repeat consists of twelve alpha satellite monomers arranged in imperfect, direct repeats. Each of the alpha X monomers is approximately 171 basepairs (bp) in length and is 60-75% identical in sequence to previously described primate alpha satellite DNAs. The twelve alpha X monomers are 65-85% identical in sequence to each other and are organized as two adjacent, related blocks of five monomers, plus an additional two monomers also related to monomers within the pentamer blocks. Partial nucleotide sequence of a second, independent copy of the 2.0 kb BamHI fragment established that the 2.0 kb repeat is, in fact, the unit of amplification on the X. Comparison of the sequences of the twelve alpha X monomers allowed derivation of a 171 bp consensus sequence for alpha satellite DNA on the human X chromosome. These sequence data, combined with the results of filter hybridization experiments of total human DNA and X chromosome DNA, using subregions within the 2.0 kb repeat as probes, provide strong support for the hypothesis that individual human chromosomes are characterized by different alpha satellite families, defined both by restriction enzyme periodicity and by chromosome-specific primary sequence.

Base Sequence↗
PubMedDate not supplied

Induced chromosomal aberrations and linkage group-chromosome correlation in Anopheles stephensi.

Genetic and cytogenetic investigations of 14 strains of Anopheles stephensi with induced chromosomal aberrations have resulted in the assignment of the three linkage groups to their respective chromosomes. In addition, the correlation between the ovarian polytene chromosomes and the mitotic chromosomes was demonstrated. Indirect evidence for the presence of heterochromatic segments in the chromosomal complement was found.

Animals↗
PubMed2001

Chromosome-specific single-locus FISH probes allow anchorage of an 1800-marker integrated radiation-hybrid/linkage map of the domestic dog genome to all chromosomes.

We present here the first fully integrated, comprehensive map of the canine genome, incorporating detailed cytogenetic, radiation hybrid (RH), and meiotic information. We have mapped a collection of 266 chromosome-specific cosmid clones, each containing a microsatellite marker, to all 38 canine autosomes by fluorescence in situ hybridization (FISH). A 1500-marker RH map, comprising 1078 microsatellites, 320 dog gene markers, and 102 chromosome-specific markers, has been constructed using the RHDF5000-2 whole-genome radiation hybrid panel. Meiotic linkage analysis was performed, with at least one microsatellite marker from each dog autosome on a panel of reference families, allowing one meiotic linkage group to be anchored to all 38 dog autosomes. We present a karyotype in which each chromosome is identified by one meiotic linkage group and one or more RH groups. This updated integrated map, containing a total of 1800 markers, covers >90% of the dog genome. Positional selection of anchor clones enabled us, for the first time, to orientate nearly all of the integrated groups on each chromosome and to evaluate the extent of individual chromosome coverage in the integrated genome map. Finally, the inclusion of 320 dog genes into this integrated map enhances existing comparative mapping data between human and dog, and the 1000 mapped microsatellite markers constitute an invaluable tool with which to perform genome scanning studies on pedigrees of interest.

Animals↗
PubMed2002

The human Hox-bearing chromosome regions did arise by block or chromosome (or even genome) duplications.

Many chromosome regions in the human genome exist in four similar copies, suggesting that the entire genome was duplicated twice in early vertebrate evolution, a concept called the 2R hypothesis. Forty-two gene families on the four Hox-bearing chromosomes were recently analyzed by others, and 32 of these were reported to have evolutionary histories incompatible with duplications concomitant with the Hox clusters, thereby contradicting the 2R hypothesis. However, we show here that nine of the families have probably been translocated to the Hox-bearing chromosomes more recently, and that three of these belong to other chromosome quartets where they actually support the 2R hypothesis. We consider 13 families too complex to shed light on the chromosome duplication hypothesis. Among the remaining 20 families, 14 display phylogenies that support or are at least consistent with the Hox-cluster duplications. Only six families seem to have other phylogenies, but these trees are highly uncertain due to shortage of sequence information. We conclude that all relevant and analyzable families support or are consistent with block/chromosome duplications and that none clearly contradicts the 2R hypothesis.

Chromosome Mapping↗
PubMed2005

Lack of mitochondrial DNA divergence between chromosome races of the common shrew, Sorex araneus, in Sweden. Implications for interpreting chromosomal evolution and colonization history.

The common shrew, Sorex araneus, has one of the most variable karyotypes among mammals, displaying numerous chromosome races throughout its distribution. The six chromosome races present in Sweden can be categorized in two different karyotypic groups, the west and north European karyotypic groups (western and northern). Three races belonging to the western group are considered to have arisen through whole arm reciprocal translocations (WARTs). Race formation through this process requires a bottleneck event. In the present study we sequenced a part of the mitochondrial DNA (mtDNA) genome to investigate molecular differences between the chromosome races in Sweden. We found no mtDNA differentiation between the mainland chromosome races or the karyotypic groups. Genetic variation is as large between populations within a race as between populations among the races or karyotypic groups, suggesting that the karyotypic groups might have originated in a common glacial refugium. The noticeable exception is the Oland race, which shows higher mtDNA diversity compared to the other Swedish races, indicating a divergent origin difficult to explain. Mitochondrial DNA variation in Sweden suggests that most haplotypes arose in situ and that the populations has undergone a rapid size expansion. Altogether, the mtDNA data are in agreement with the WART hypothesis, which still holds as the most plausible variant of karyotype evolution for three of the chromosome races of the common shrew in Sweden.

Animals↗
PubMed1984

Influence of long-term administration of anticonvulsants on human somatic chromosomes. Relationships of chromosome aberrations to plasma concentration, dosage and duration of anticonvulsants.

Chromosomal aberrations of 16 patients who have taken anticonvulsants for a long time were examined, and the following results were obtained. (1) There was no definite relation between the dosage of anticonvulsants and the incidence of abnormal cells, but positive correlation was recognized between the plasma concentration of the agents and the incidence of abnormal cells. (2) A significant correlation was recognized between the duration of administration and the incidence of abnormal cells. (3) The mean duration of drug administration was 16.9 years, with the incidence of abnormal cells of more than 15% in a group of 12 abnormal female subjects, and 8.1 years with an incidence of abnormal cells of less than 15% in a group of 9 normal subjects. (4) Morphological chromosome aberrations observed were mostly gaps and breaks. Any increase of exchange-type aberration was not recognized. It is conceivable that plasma factors might be more significant than the direct action from drugs as a mechanism of chromosome aberration. We speculate about the effects of lymphocyte chromosome aberration on living bodies, and the necessity of chromosome examination for the patients on long-term anticonvulsant therapy.

Adolescent↗