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Results for “karyotype evolution”

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PubMed2001

[Chromosomal evolution of the Common Shrew Sorex araneus L.from the Southern Ural and Siberia in the postglacial period].

This paper summarizes a series of studies on chromosomal geography of the common shrew Sorex araneus L. in Siberia and the Southern Urals. Chromosomal races inhabiting the Southern Urals and the Western Siberian Plain sequentially replace each other in the latitudinal direction. In this region, karyotypes of each two adjacent races differ from each other by a single whole-arm reciprocal translocation. In the Eastern Siberian branch, the neighboring races differ mainly in the number or set of metacentric chromosomes. Analysis of the race distribution in the common shrew in the context of paleophysiology of the glacial period allowed us to reconstruct the sequence of events leading to the establishment of the present-day structure of the species.

Animals↗
PubMed1984

Two monotreme cell lines, derived from female platypuses (Ornithorhynchus anatinus; Monotremata, Mammalia).

Two diploid platypus cell lines, designated Oa-1F and Oa-2F, have been derived from the toe webs of two females. The development and growth characteristics of the lines are described and G-banded karyotypes presented (the first reported for the platypus). The availability of these lines will greatly facilitate chromosome and gene mapping studies of the platypus and permit the extension of comparative studies of mammalian chromosome and genome evolution to the monotremes.

Animals↗
PubMed2004

Phylogeographical patterns of genetic divergence and speciation in African mole-rats (Family: Bathyergidae).

African mole-rats are subterranean Hystricomorph rodents, distributed widely throughout sub-Saharan Africa, and displaying a range of social and reproductive strategies from solitary dwelling to the 'insect-like' sociality of the naked mole-rat, Heterocephalus glaber. Both molecular systematic studies of Rodentia and the fossil record of bathyergids indicate an ancient origin for the family. This study uses an extensive molecular phylogeny and mitochondrial cytochrome b and 12s rRNA molecular clocks to examine in detail the divergence times, and patterns of speciation of the five extant genera in the context of rift valley formation in Africa. Based on a value of 40-48 million years ago (Myr) for the basal divergence of the family (Heterocephalus), we estimate divergence times of 32-40 Myr for Heliophobius, 20-26 Myr for Georychus/Bathyergus and 12-17 Myr for Cryptomys, the most speciose genus. While early divergences may have been independent of rifting, patterns of distribution of later lineages may have been influenced directly by physical barriers imposed by the formation of the Kenya and Western Rift, and indirectly by accompanying climatic and vegetative changes. Rates of chromosomal evolution and speciation appear to vary markedly within the family. In particular, the genus Cryptomys appears to have undergone an extensive radiation and shows the widest geographical distribution. Of the two distinct clades within this genus, one exhibits considerable karyotypic variation while the other does not, despite comparatively high levels of sequence divergence between some taxa. These different patterns of speciation observed both within the family and within the genus Cryptomys may have been a result of environmental changes associated with rifting.

Africa↗
PubMed1991

Bilateral ovarian carcinoma: cytogenetic evidence of unicentric origin.

Cytogenetic analyses were performed on the tumors from both ovaries in 15 patients with bilateral ovarian carcinoma. In 4 of them, omental implants were also examined. Abnormal karyotypes were detected in 11 cases. The baseline karyotypes in the 2 tumorous ovaries were identical in each patient, indicating that bilateral ovarian cancer develops by metastatic spreading. There was no clear-cut evidence of differences in the clonal evolution between the tumors of the 2 ovaries, and hence the side harboring the primary tumor could never be determined. The metastatic nature of the omental implants was proved by the fact that their karyotypes were indistinguishable from those of the ovarian tumor tissue.

Adenocarcinoma↗
PubMed1985

Characteristics of a conserved 1,579-bp highly repetitive component in the killer whale, Orcinus orca.

A tandemly organized, highly repetitive DNA component of the killer whale was sequenced. The length of the repeat was 1,579 bp. This unit, which characterizes all delphinids, shows stringent hybridization homology with a 1,740-bp repeat that is characteristic of all other cetacean families. The 1,579-bp component comprises approximately 15% of the killer-whale genome, in which it is repeated 4-5 X 10(5) times. Computer analysis of the sequence showed no linear repetition within the component. This indicates that the 1,579-bp unit has not evolved by amplification of shorter repeats. Several inverted repeats of substantial length were found in the 1,579-bp unit. The most conspicuous of these was a 72-bp sequence that deviated from matching in only three positions. The 72-bp sequence occurs within an open reading frame 330 bp in length. Transcriptional activity was registered in the cloned repeat in a cell-free system. The length of the transcript was approximately 340 nucleotides. The chromosomal localization of the 1,579-bp repeat was determined by in situ hybridization. The repeat was present in eight of 21 autosomal pairs and was found in almost all C-band-positive (constitutive heterochromatin) regions of the karyotype.

Animals↗
PubMed1987

Nonrandom chromosomal changes in human solid tumors: application of an improved culture method.

A cytogenetic study was performed on 48 primary human benign, borderline malignant, and malignant solid tumors from more than 10 different tissues. An improved cell culture method using an extracellular matrix substrate and a polyvalent serum-free medium was applied, which ensured a success rate of about 68%. The results disclosed a nonrandom involvement of chromosomes 1, 3, and 7 (especially duplication of chromosome 7) in numerical changes and a clustering of breakpoints on chromosomes 1, 3, 7, and 11. These data indicate that some chromosomal changes are shared by various types of tumors, suggesting some common genetic clonal evolution pathways.

Chromosome Aberrations↗
PubMed1990

Cytogenetic and molecular approaches of polyploidization in colorectal adenocarcinomas.

We present the cytogenetic analysis of 23 cases of polyploid colorectal adenocarcinomas. We took advantage of the high intratumoral heterogeneity of the karyotypes to identify clones, subclones, and cell-to-cell variations. This allowed us to reconstruct the chromosomal evolution of each tumor and to propose a schema of the chromosomal changes in relation to the endoreduplication process. All but one case were characterized by a relative deficiency of chromosomes 17p and 18. Other deficiencies affecting the late-replicating X, and to a lesser degree, 1p, 5q, 14, 15, 8p, 10, 21, and 4, and excesses affecting the early-replicating X, 8q, 13, 16, 17q, and 11 were frequently associated. This pattern of imbalances is very similar to that of the monosomic type previously described in near-diploid tumors. The pattern of the 23rd tumor corresponded to those of the trisomic type tumors. These data largely confirm the existence of two distinct processes of chromosomal evolution in colorectal adenocarcinomas, with a strong tendency to undergo endoreduplication for the monosomic type near-diploid tumors. To correlate cytogenetic and molecular data, allelic losses analyses were investigated for probes of chromosomes 17p and 18. In all 12 informative tumors, a loss of heterozygosity for probes of the short arm of chromosome 17 indicated the occurrence of a rearrangement of chromosome 17 before the endoreduplication. The same was true for allelic losses for probes of chromosome 18 found in 11 of 12 informative tumors. The correlation between cytogenetic and molecular data is thus excellent and indicates that losses of 17p and 18 are early events in the tumor process.

Adenocarcinoma↗
PubMed2002

Evolutionary significance of chromosome changes in northeastern Asiatic red-backed voles inferred with the aid of intron 1 sequences of the G6pd gene.

To evaluate the evolutionary significance of karyotypic characters in red-backed voles (Rodentia, Arvicolinae, genera Clethrionomys and Eothenomys) from northeastern Asia, we constructed phylogenetic trees based on intron 1 sequences (ca. 580 bp) of the X-linked gene G6pd. Phylogenetic trees, constructed using neighbor-joining and maximum-likelihood methods, revealed two major clades in red-backed voles corresponding to the glareolus- and the rufocanus-cytotypes defined by a reciprocal translocation between chromosomes 1 and 9 based on G-band patterns. If confirmed, two types of X chromosome, acrocentric X and subtelocentric X, which have often been claimed to be traits of evolutionary and taxonomic significance, should be considered as examples of homoplasy because they occur sporadically in members of both rufocanus- and glareolus-cytotypes in red-backed voles.

Animals↗
PubMed2004

Heterochromatin characterization of four fish species of the family Loricariidae (Siluriformes).

The karyotypic structures and the composition and distribution of the heterochromatin in the karyotypes of four catfish species belonging to four Loricariidae subfamilies were analysed, namely: Neoplecostomus microps (Neoplecostominae) with 2n=54 chromosomes, Harttia loricariformis (Loricariinae) with 2n=56 chromosomes, Hypostomus affinis (Hypostominae) with 2n=66 chromosomes and Upsilodus sp. (Upsilodinae) with 2n=96 chromosomes. The amount and composition of heterochromatin was quite unequal among the studied species, being copious and mainly GC-rich in Upsilodus sp. and scarce and balanced in H. loricariformis. All of the H. affinis heterochromatin is GC-rich and related with nucleolar organizing regions. N. microps show low quantity of interstitial and GC-rich heterochromatin, one of them being related with NORs. Trends in the macrokaryotypic diversification as well as in the distribution pattern of the heterochromatin are discussed.

Animals↗
PubMed2006

Complex evolution of X and Y autosomal translocations in the giant mole-rat, Cryptomys mechowi (Bathyergidae).

Cross-species chromosome painting was used to determine homologous chromosomal regions between two species of mole-rat, the naked mole-rat, Heterocephalus glaber (2n = 60), and the giant mole-rat, Cryptomys mechowi (2n = 40), using flow-sorted painting probes representative of all but two of the H. glaber chromosomal complement. In total 43 homologous regions were identified in the C. mechowi genome. Eight H. glaber chromosomes are retained in toto in C. mechowi, and 13 produce two or more signals in this species. The most striking difference in the karyotypes of the two taxa concerns their sex chromosomes. The H. glaber painting probes identified a complex series of translocations that involved the fractionation of four autosomes and the subsequent translocation of segments to the sex chromosomes and to autosomal partners in the C. mechowi genome. An intercalary heterochromatic block (IHB) was detected in sex chromosomes of C. mechowi at the boundary with the translocated autosomal segment. We discuss the likely sequence of evolutionary events that has led to the contemporary composition of the C. mechowi sex chromosomes, and consider these in the light of prevailing views on the genesis of sex chromosomes in mammals.

Animals↗
PubMed1994

Karyotype and prognosis in non-Hodgkin lymphoma.

In malignant non-Hodgkin lymphomas (NHL), cytogenetic analysis may provide prognostic information including prediction of histologic evolution and responsiveness to therapy. In this study, we correlate clinical data and chromosomal aberrations in 70 adult patients with newly diagnosed NHL followed for a median of 20 months. Clonal aberrations were detected in 68/70 patients (97%). Besides t(2;5)(p23;q35), observed exclusively in three patients with anaplastic large cell lymphoma, Ki-1 positive, none of the characteristic aberrations observed was specific for a given histological subtype. Aberrations of chromosome 7 (n = 21) occurred in all histological subtypes together with aberrations of chromosome 3 and of the short arm of chromosome 17. They were clinically associated with a high serum lactate dehydrogenase level (LDH) and a trend to short survival. Anomalies of the long arm of chromosome 13 (n = 10) were found in patients with high grade B-cell lymphomas and bulky disease. In t(14;18)(q32;q21) bearing lymphomas (n = 27), distinct patterns of additional aberrations were observed in low grade and high grade lymphomas: trisomy 3 and trisomy 18 occurred concomitantly in high grade lymphomas (n = 6, p < 0.001) as well as aberrations of 1q, 5q, 6q and +der (18)(q21). In conclusion, cytogenetic analysis provides information about the complexity of genetic changes in NHL. These changes act not only as indicators of disease activity, but influence clinical outcome as demonstrated by their stringent correlation to the International Index and might reveal more general rules of tumor growth and spreading.

Adolescent↗
PubMed1996

Metaphase karyotypes of Anopheles of Thailand and Southeast Asia. VI. The Pyretophorus and the Neomyzomyia series, subgenus Cellia (Diptera:Culicidae).

A total of 6 species of the Pyretophorus (4 species) and Neomyzomyia (2 species) series of the subgenus Cellia of Anopheles were used for metaphase karyotype analysis. Anopheles subpictus and An. vagus exhibit 4 and 2 forms of mitotic karyotypes, respectively, which are attributable to different types of Y chromosomes. Such distinctive mitotic chromosomes may reflect interspecies differences within each of these 2 taxa. Two distinct species, An. indefinitus and An. sundaicus, show similar metaphase karyotypes, particularly with regard to the size and shape of the sex chromosomes. Likewise, An. tessellatus and An. kochi, which are distinct species of the Neomyzomyia Series, also have metaphase karyotypes that resemble each other. They exhibit a typical feature of telocentric sex chromosomes resembling those of the An. dirus complex and the other species of the Leucosphyrus Group. Like the other cases of the Oriental Anopheles, heterochromatin has played a significant role in chromosome evolution of the 6 species.

Animals↗
PubMed2002

Chromosomal abnormalities in T-cell large granular lymphocyte leukaemia: report of two cases and review of the literature.

Cytogenetic information on T-cell large granular lymphocyte leukaemia (T-LGL; large granular lymphocytosis) is limited. We report two cases of T-LGL with unusual karyotypic aberrations. The first case showed a novel inv(7)(p15q22) as the sole chromosomal abnormality, while the second case showed an inv(14)(q11q32) with evidence of clonal evolution. The breakpoints 7p14-p15 and 14q11 coincide with the T-cell receptor (TCR)-gamma and TCR-alpha/TCR-delta gene loci respectively. This is the first report describing the possible involvement of T-cell receptor genes in karyotypic aberrations in T-LGL.

Adult↗
PubMed1988

t(1;7) in acute myeloblastic leukemia following myelodysplastic syndrome (RAEB-T).

A case is described of myelodysplastic syndrome (MDS) refractory anemia type with an excess of blasts in transformation with early leukemic evolution (AML-M1). All bone marrow cells examined showed an unbalanced translocation t(1;7). The karyotype was 45, xy, -21, -7, + der dic t(1;7) (q12;q21). There are reports in the literature of the translocation t(1;7) (p11;p11), which leads to trisomy of the long arms of chromosome #1 and monosomy of the long arms of chromosome #7. In the case here described the breakpoints of the chromosomes involved in the translocation differ from the classic ones: in this case there is trisomy of the region 1q12----1qter and monosomy of the region 7q21----7qter. Some clinical and cytogenetic considerations are suggested.

Adult↗
PubMed1980

Chromosomal evolution of the great apes and man.

A study of all the chromosomal changes that have occurred during evolution of the great apes and man gives an indication of the phylogeny of these species. Their karyotypes differ from one another by a dozen chromosomal changes. The karyotype of their ancestor was very similar to that of living orangutans. Reconstruction of the sequence of the chromosomal changes indicates that, after the isolation of the orang-utan, a common ancestral population existed for the other species. Then, each branch leading to the living genera was independently isolated. The karyotype of the chimpanzee is an intermediary stage between that of man and the gorilla for some chromosomes. The human karyotype is less differentiated than that of the chimpanzee or the gorilla.

Animals↗
PubMed1992

Regional localization of the owl monkey MYB and OMLA gene loci.

Regional mapping of the MYB and OMLA gene loci to their respective sites on owl monkey chromosome 9q of karyotype VI support the proposed homology of this primate chromosome with the human chromosome 6 and the premise that structural rearrangement on this putative homolog occurred during evolutionary divergence of the higher primates.

Animals↗
PubMed2004

[Benign familial Degos disease].

INTRODUCTION: Degos' disease or atrophic malignant papulosis is defined by porcelain white cutaneous lesions with atrophic scarring, often associated with severe and fatal systemic involvement (visceral and neurological). Benign forms are rare or under-reported and the familial forms are exceptional. It is a very rare disease, only two hundred cases have been reported in the literature with a sex ratio of 3M/1F. The pathogenesis of Degos' disease remains controversial. The exceptional observation of familial form raises the question of a genetic predisposition of this disease or an infectious aetiology with a low virus. OBSERVATION: A 41 year-old woman was known to have Degos' disease for 26 years with only cutaneous manifestations. One of her two sons developed atrophic cutaneous lesions at the age of 20. In both patients, no thrombotic or immunological abnormalities were found. The karyotype was performed with normal results. DISCUSSION: Degos' disease or malignant atrophic papulosis can have a long lasting benign evolution. Our patient, who had presented a benign form for 26 years, had the longest evolution ever documented in literature. We cannot be sure that her son will have a benign course of his Degos' disease because the diagnosis is recent and because the systemic involvement can appear after many years of evolution. In the familial forms, from our study and the 31 cases previously described in the literature, with ten different families, the course of the disease seems to be less severe than in sporadic forms. Among these familial forms of Degos' disease, only 4 patients presented a malignant form, which in one case did not prove a relationship between the death and the Degos' disease. Are the sporadic forms with only skin involvement less frequently reported? Has the familial form of Degos' disease the same course as a very severe common sporadic form?

Adult↗