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PubMed1985

Early replication banding reveals a strongly conserved functional pattern in mammalian chromosomes.

One of the best documented autosomal linkage associations in man is on chromosome 1p and in the mouse on chromosome 4. On mitotic chromosomes this genetic homology is shown more clearly by early replication banding (RBG; induced by incorporation of 5'bromodeoxyuridine (BrdU) in the second half of the S phase) than by structural banding (induced on prefixed chromosomes by denaturation, RFA, or trypsin, GTG). To analyse this phenomenon in more detail, 11 chromosomal regions in man and the domestic cat with known genetic homology were compared. In four chromosome pairs RBG and GTG banding show the same degree of homology. In seven chromosome pairs the homology is more pronounced by RBG than by GTG banding. RFA banding does not reveal the same extent of homology as does RBG banding. These results clearly show a difference between the structural banding pattern, RFA and GTG, and the replication banding pattern, RBG. The following conclusions can be drawn: in chromosomal regions with homologous functions the DNA replicates in the same temporal order. Early replication banding (RBG) reveals a functional pattern in these regions which has been more strongly preserved during evolution than the underlying chromosomal DNA. Differences in chromosomal banding are most prominent in the GTG banding pattern, whereas similarities are most apparent in the RBG banding pattern.

Animals↗
PubMed1991

A new multisequence family in human.

By hybridizing total human DNA with probes derived from the extrachromosomal circular DNA fraction of cultured cells, we detected a human multisequence family, called chAB4, previously unknown. Approximately 50 copies of this sequence are located in the haploid human genome. The repetition units of chAB4 are 35 kb long and the units are tandemly arranged. DNA sequence analysis of parts of the chAB4 unit revealed no direct evidence for a possible function of the family, but possibly chAB4 harbors a gene. Family members are located on human chromosomes 1, 3, and 9 and on the short arms of chromosomes 13-15, 21, and 22. Therefore, in addition to the rDNA, chAB4 is the second class of clustered repetitive sequences with a relatively long repetition unit localized on the short arms of all acrocentric chromosomes. Some evolutionary aspects arising from the structure of chAB4, the established parts of its DNA sequences, and the chromosomal localization of this new multisequence family are discussed.

Autoradiography↗
PubMed2002

[Sex chromosome homologies between human and fish revealed by the chromosome painting method].

Human sex chromosome-specific probes were hybridized to metaphase spreads of three fish species, Monopterus albus Zuiew, Danio rerio and Mastacembelus aculeatus Basilewsky, to reveal evolutionary conservation of sex chromosomal segments between distantly related species of vertebrates. The human X chromosomal paint disclosed 4, 8, and 6 conserved syntenic segments in the karyotypes of the three fish species respectively, which were scattered in several pairs of homologous chromosomes. But no conserved segment was identified in our experiments when the human Y chromosomal probes were used. The evolution of the X chromosome of vertebrates is discussed.

Animals↗
PubMed1996

Cytonuclear genetic structure of a hybrid zone in lizards of the Sceloporus grammicus complex (Sauria, Phrynosomatidae).

Lizards of the Sceloporus grammicus complex are comprised of multiple chromosome races that form several zones of parapatric hybridization in central Mexico. We scored diagnostic mitochondrial DNA (mtDNA) haplotypes and autosomal chromosome markers in a sample of 342 lizards from one well-defined zone between 2n = 34 and 2n = 46 races. A two-part analysis was performed on this data set in an attempt to infer the predominant evolutionary forces shaping the cytonuclear structure of this zone. The complications posed by its spatial structure were addressed by analysing a hierarchical series of smaller subsamples chosen to approximate single mating units. Two critical conclusions were drawn from this first-stage analysis. First and foremost, the three chromosomes have largely concordant cytonuclear disequilibrium patterns within each subsample with adequate numbers of individuals for detecting nonrandom cytonuclear associations. This suggests that the cytonuclear structure of this zone is predominantly a result of deterministic genome-wide forces rather than genetic drift of deterministic forces specific to individual chromosomes or loci. Second, the fit of a series of migration models to the data shows that the cytonuclear structure of the subsamples is well accounted for by continued gene flow from the two parental races alone, with random mating with respect to cytonuclear genotype and no other evolutionary forces. These results motivate several further empirical and theoretical investigations to refine our understanding of the relative roles of migration and other potentially important forces such as natural selection and genetic drift, in this and other hybrid zones.

Animals↗
PubMed1988

Chromosomal involvement secondary to -22 in human meningiomas.

Cytogenetic analyses have been performed on cultures in vitro from 32 human meningiomas, seeking chromosomal anomalies in addition to characteristic monosomy 22. Eight cases showed stem lines with normal karyotype, whereas, monosomy 22 as the only chromosomal deviation characterized the stem line of ten tumors. In 14 samples stem lines or modal numbers displaying numerical deviations (other than -22) and/or structural rearrangements were found. A hyperdiploid modal number was present in three, whereas, it was hypodiploid in the remainder. Numerical deviations in these tumors involved mainly #14 by losses, and also #22; recurrent structural rearrangements involving 1p and 11p were also characteristic features. Thus, these results could imply that involvement of #14, 1p, and 11p would be a form of clonal evolution secondary to monosomy 22 in certain meningiomas.

Adult↗
PubMed2004

Genetic variation in a cline in a living intertidal snail arose in the Neogastropoda over 100 million years ago.

To understand how species adapt and evolve it is necessary to appreciate the relationship between genetic variation and the environment. Here, the fossil record and molecular data from different lineages of the marine Gastropoda are used to understand the evolution of genetic variations found in the nuclear gene for mitochondrial malate dehydrogenase (mMDH; EC 1.1.1.37) in the living intertidal Muricid snail, Nucella lapillus. Assuming a molecular clock, DNA sequences of mMDH indicate that two variants found in N. lapillus, mMDH(9) and mMDH(10), may have arisen as long as 144 MY (million years) ago and at least prior to the evolution of the Muricidae approximately 112-90 MY ago. The Muricidae contain by far the greatest majority of the Neogastropoda specialized for life in the intertidal habitat. In N. lapillus the mMDH(9) and mMDH(10) variants covary with variations in other biochemically defined loci, inherited phenotypic traits (shell shape and physiology) and karyotype frequencies to differentiate two distinct nuclear haplotypes that are associated with different temperature environments. The variations in shell shape that are associated with the haplotypes of N. lapillus represent adaptations to temperature stress and similar variations occur in other related intertidal molluscs whose lineages are much older than Nucella, which arose around 25 million years ago. It is suggested that the divergence of the mMDH variants found in N. lapillus may reflect an ancient genetic event, such as a chromosomal mutation, perhaps involving variation in other linked traits that together became important in the subsequent evolution of the marine Gastropoda.

Adaptation, Biological↗
PubMed1992

Wiedemann-Beckwith syndrome: clinical, cytogenetical and radiological observations in 39 new cases.

Thirty-nine patients (82% under 1 year of age) with Wiedemann-Beckwith syndrome (WBS) were prospectively studied. To evaluate the somatometric data the normal range was set out at mean +/- 2 SD. The relevant physical findings were a characteristic face, non increased mean height and weight, normal head circumference, defective abdominal wall, a predominance of the upper segment, and tibial bowing. Mental retardation was documented in 5 cases but in only 1 it was related to hypoglycemia. The 32 cases karyotyped were normal. Since neonatal hypoglycemia is frequent (34.3% in our series) and potentially deleterious for the CNS we propose to monitor the glycemia every 6 h during the first 3 days in WBS newborns in order to correct glycemia below of 2.6 mmol/l (46.8 mg/dl) according to recent studies. The comparison with previous large series enabled us to precise the frequency, onset and evolution of the main stigmata.

Adolescent↗
PubMed1990

Chromosomal evolution in secretory and nonsecretory subline of MOPC 21.

Murine myeloma cell lines are noted for the instability of their immunoglobulin genes and the production of nonsynthesizing variants. In this study, the synthesizing line P3-X63-Ag8 (P3) and its nonsynthesizing subline X63-Ag8-653 (653) were karyotyped and rearrangements of the immunoglobulin carrying chromosomes were investigated. Loss of immunoglobulin synthesis was associated with a reduction in the number of immunoglobulin-carrying chromosomes. When these findings were analyzed in light of published molecular data, it appeared that loss of immunoglobulin synthesis in 653 probably occurred as a result of immunoglobulin gene loss. An unusual finding was the absence of the t(12;15) chromosome in both P3 and 653 cell lines. It was concluded that the t(12;15) chromosome, carried by MOPC 21, has evolved into an unrecognizable form.

Animals↗
PubMed1992

Acute leukemia with t(1;3)(p36;q21), evolution to t(1;3)(p36;q21), t(14;17)(q32;q21), and loss of red cell A and Le(b) antigens.

At transformation of refractory anemia with ring sideroblasts to acute nonlymphocytic leukemia (ANLL) the bone marrow cells of a 75-year-old woman showed three different karyotypes, i.e., 46,XX,46,XX,t(1;3)(p36;q21) and 46,XX,t(1;3)(p36;q21),t(14;17)(q32;q21). She received no antileukemic therapy, and 1 year later, all her bone marrow cells were t(1;3)(p36;q21),t(14;17)(q32;q21). In association with the onset and first 11 months of ANLL, the platelet count increased 10-fold to a peak of 750 x 10(9)/L, providing further evidence that the t(1;3)(p36;q21) translocation causes stimulation of thrombopoiesis. Six months after transformation, her red cells showed reduced expression of A and Leb antigens. Serum alpha-n-3-acetylgalactosaminyl transferase (blood group A transferase) and red cell adenylate kinase were both reduced. The genes for both these substances are at 9q34, which suggests an abnormality here, although cytogenetically chromosome 9 appeared normal. This is the first case with t(1;3)(p36;q21) to show concurrent loss of red cell antigens and the first report detailing the course of untreated ANLL with t(1;3)(p36;q21).

ABO Blood-Group System↗
PubMed2001

Spectral karyotyping suggests additional subsets of colorectal cancers characterized by pattern of chromosome rearrangement.

The abundant chromosome abnormalities in most carcinomas are probably a reflection of genomic instability present in the tumor, so the pattern and variability of chromosome abnormalities will reflect the mechanism of instability combined with the effects of selection. Chromosome rearrangement was investigated in 17 colorectal carcinoma-derived cell lines. Comparative genomic hybridization showed that the chromosome changes were representative of those found in primary tumors. Spectral karyotyping (SKY) showed that translocations were very varied and mostly unbalanced, with no translocation occurring in more than three lines. At least three karyotype patterns could be distinguished. Some lines had few chromosome abnormalities: they all showed microsatellite instability, the replication error (RER)+ phenotype. Most lines had many chromosome abnormalities: at least seven showed a surprisingly consistent pattern, characterized by multiple unbalanced translocations and intermetaphase variation, with chromosome numbers around triploid, 6-16 structural aberrations, and similarities in gains and losses. Almost all of these were RER-, but one, LS411, was RER+. The line HCA7 showed a novel pattern, suggesting a third kind of genomic instability: multiple reciprocal translocations, with little numerical change or variability. This line was also RER+. The coexistence in one tumor of two kinds of genomic instability is to be expected if the underlying defects are selected for in tumor evolution.

Colorectal Neoplasms↗
PubMed1999

Genome structure and evolution in the allohexaploid weed Avena fatua L. (Poaceae).

Allohexaploid wild oat, Avena fatua L. (Poaceae; 2n = 6x = 42), is one of the world's worst weeds, yet unlike some of the other Avena hexaploids, its genomic structure has been relatively little researched. Consequently, in situ hybridisation was carried out on one accession of A. fatua using an 18S-25S ribosomal DNA (rDNA) sequence and genomic DNA from A. strigosa (AA-genome diploid) and A. clauda (CC-genome diploid) as probes. Comparing these results with those for other hexaploids studied previously: (i) confirmed that the genomic composition of A. fatua was similar to the other hexaploid Avena taxa (i.e., AACCDD), (ii) identified major sites of rDNA on three pairs of A/D-genome chromosomes, in common with other Avena hexaploids, and (iii) revealed eight chromosome pairs carrying intergenomic translocations between the A/D- and C-genomes in the accession studied. Based on karyotype structure, the identity of some of these recombinant chromosomes was proposed, and this showed that some of these could be divided into two types, (i) those common to all hexaploid Avena species analysed (3 translocations) and (ii) one translocation in this A. fatua accession not previously observed in reports on other hexaploid Avena species. If this translocation is found to be unique to A. fatua, then this information, combined with more traditional morphological data, will add support to the view that A. fatua is genetically distinct from other hexaploid Avena species and thus should retain its full specific status.

Avena↗
PubMed1993

Phenotypic and genotypic characterization of Hodgkin's disease.

Although a few studies have reported clonal cytogenetic changes in Hodgkin's disease (HD), their correlation with histologic groups is poorly defined. This is because of insufficient numbers of clonally abnormal cases ascertained in each of these studies, an inherent problem associated with the cytogenetic studies of HD. In this report we present results of pathologic, phenotypic, and genetic studies on 29 HD tumors consecutively ascertained by us and the results of a comprehensive analysis of the cytogenetic data available in the literature. In our series 75% of the tumors were positive for Epstein-Barr virus (EBV) by polymerase chain reaction (PCR) assay. A higher frequency of EBV-positive tumors showed clonal karyotypic abnormalities than the EBV-negative tumors. Unlike the case in the previous reports, none of the 24 tumors studied by PCR showed the presence of t(14;18) (q32;q21)-carrying cells. From the comprehensive analysis of the literature, we identified recurring nonrandom numerical changes, deletions, and chromosome breaks in HD. Some of these are associated either with nodular sclerosis or with mixed cellular histologies. A comparison of the pattern of these nonrandom cytogenetic changes in HD and those reported for non-Hodgkin's lymphomas (NHL) identified common deletions and breaks between them. These common genetic lesions probably play a role in disease evolution.

Adolescent↗
PubMed2006

The spectrum of parathyroid gland dysfunction associated with the microdeletion 22q11.

OBJECTIVE: Clinical features associated with microdeletion of chromosome 22q11 (del(22)(q11)) are highly variable. Increased awareness of this condition is needed among specialists such as endocrinologists to reduce diagnostic delay and improve clinical care. The purpose of this study was to describe the phenotype of patients with del(22)(q11), focusing on parathyroid gland dysfunction. DESIGN AND METHODS: Charts of 19 patients, including one kindred of three, known to have del(22)(q11) diagnosed by fluorescence in situ hybridization (FISH) were reviewed from the register of the department of Medical Genetics. Major clinical features including hypoparathyroidism phenotype were collected. RESULTS: Parathyroid dysfunction was present in 8 out of 16 patients (50%). Six patients were diagnosed with overt hypoparathyroidism. Hypocalcemia manifested as laryngeal stridor within the first days of life (n = 3), seizures in infancy (n = 1) and adolescence (n = 2). The connection between hypoparathyroidism and diagnosis of del(22)(q11) was belated at the median age of 18 years. One patient had presented with transient neonatal hypoparathyroidism, and one patient had latent hypoparathyroidism. Within the kindred family, the phenotype variability including that of parathyroid dysfunction was as marked as between unrelated individuals. Standard karyotype failed to detect the deletion in 15 out of 19 cases. CONCLUSIONS: Abnormal parathyroid function in the del(22)(q11) ranges from severe neonatal hypocalcemia to latent hypoparathyroidism. Del(22)(q11) should be considered as a potential cause of hypocalcemia even in young adult. When suspected, the diagnosis requires investigation by FISH. Furthermore, long-term calcemia follow-up is needed in normocalcemic patients with del(22)(q11) because of the possible evolution to hypocalcemic hypoparathyroidism.

Adolescent↗
PubMed1994

Acute myeloid leukemia (AML-M1) with multiple trisomies and t(8;21)(q22;q22).

Cytogenetic analysis of an acute myeloid leukemia (AML-M1) showed the karyotype 53,XY, +6, +8,t(8;21)(q22;q22), +9, +10, +13, +19, +21. Only one AML with a massively hyperdiploid karyotype (> 50 chromosomes) and t(8;21) has been published before. A comparison of the two cases reveals similarities both with regard to the morphologic subtype (M1) and to which chromosomes were trisomic (+6, +8, +13, +19, and +21 were found in both cases). We surmise that the t(8;21) was the primary chromosomal abnormality and that the set of multiple trisomies occurred secondarily; this pattern of clonal evolution may have favored a more immature leukemic phenotype in these two cases than is regularly seen in t(8;21)-associated leukemias.

Child↗
PubMed2004

Laying the cytotaxonomic foundations of a new model grass, Brachypodium distachyon (L.) Beauv.

Brachypodium distachyon is a ubiquitous, temperate grass species which is being developed and exploited as an alternative model to rice, in order to gain access to important syntenic regions of the genomes of less tractable relatives such as wheat. As part of this initiative, this paper describes for the first time the cytotaxonomy of members of the polyploid series of this species, and challenges the assumption that the series evolved simply by chromosome doubling. In situ hybridization using genomic DNA probes and rDNA markers uncovers a hybrid origin of several of the polyploid ecotypes, and sheds light upon the complex evolution of this species and its close relatives.

Chromosome Painting↗
PubMed1994

[Evolutive epidemiologic profile of myelodysplastic syndromes (1959-1993). Comparative study with acute myeloid leukemia and aplastic pancytopenias].

PURPOSE: To compare the maximum epidemiologic data attained from myelodysplastic syndromes (MDS) with those of two main panmyelopathies, namely acute myeloblastic leukaemia (AML) and aplastic pancytopenia (AP). PATIENTS AND METHODS: A retrospective analysis was carried out on 21,135 patients included in the Bone Marrow Study Registry of the Jiménez Díaz Foundation along 35 years (1959-1993). The data were grouped into seven five-year periods. Of these, in the first three the study was performed on bone-marrow aspirates; after 1976 the histopathological study of bone-marrow biopsies was introduced, and since 1979 the karyotype has been regularly examined. The MDS were classified in accordance with the FAB system. With these premises borne in mind, the following aspects were considered: diagnostic interpretation of MDS along the years; diagnostic incidence of MDS, AML and AP in each of the five-year periods; relative frequency of those diagnosis with respect to the total number of cases; evolutive profile of sex and age at diagnosis; quantitative significance of secondary MDS-AL and toxic AP along the years; MDS subtypes and their epidemiologic characteristics. RESULTS: A total of 510 MDS, 610 AML and 223 AP cases were identified. With respect to the sex of the MDS patients, some changes have been seen along the years, from an M/F ratio of 1.9 to 1.0; and the mean age at diagnosis raised from 53.3 years (with only 1.7% of the cases over 65 years of age) to 71.4 years (with 76.9% of the cases over 65 years of age), all this within the 1959-1989 period. The incidence of AML and AP has remained stable for the last 20 years; on the contrary, MDS have been increasing continuously along the 35 years of the study, which poses for a higher number of new cases in every period (from 35 to 119) and also for a higher relative frequency in the registry (from 1.37% to 4.40%) within the period 1959-1989. Valuable toxic history was progressively increasing in secondary MDS-AML and progressively decreasing in AP. With respect to the FAB subtypes of MDS, and taking into account the last of the five-year periods, the most frequently diagnosed were RA and RSA followed by RAEB, CMML and RAEB-T. CONCLUSIONS: The increment of the incidence of MDS cases correlates significantly with the increment of the patients aged over 65 years. This incidence appears to be scarcely influenced by previous mutagenic agents (radiotherapy, chemotherapy) and might be due to a better understanding of MDS.

Acute Disease↗