Systematic problems in the amphibian family Leptodactylidae (Anura) as indicated by karyotypic analysis.
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Animals↗
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Molecular phylogenetics of howler monkeys (Alouatta, Platyrrhini). A comparison with karyotypic data.
Molecular phylogenetic analyses of seven Brazilian Alouatta species, based on cytochrome b DNA sequence data were carried out. Parsimony and neighbor joining topologies grouped Alouatta belzebul and A. fusca as sister groups in one clade while another, well-supported clade contained A. seniculus as the most basal offshoot, followed by A. nigerrima as a sister lineage of A. macconnelli/A. stramineus. Estimates of inter-specific sequence divergence were generally low, and estimates of the time of divergence indicated that the main Alouatta lineages emerged during a short evolutionary interval. A comparison with karyotypic data confirmed the molecular topology showing a closer relationship between A. macconnelli and A. stramineus in respect to A. nigerrima. It also showed that the XX/XY sex chromosome system was maintained in several lineages while the X1X2Y/X1X1X2X2 system appeared independently at least three times during the radiation of howler monkeys. Moreover, the X1X2Y1Y2/X1X1X2X2 system might have appeared once or, alternatively, twice and independently.
Alouatta↗
Karyotype studies in South American species of Solanum subgen. Leptostemonum (Solanaceae).
Mitotic chromosome numbers and karyotypes of 13 South American species (12 native and one naturalized) from four sections of SOLANUM subgen. LEPTOSTEMONUM were studied. Chromosome numbers of S. ACERIFOLIUM, S. AENICTUM, S. CONDITUM, S. CONSIMILE, S. INCARCERATUM, and S. PLATENSE are reported for the first time. The number 2n = 24 was found in most species, while 2n = 22 was found in S. MAMMOSUM and S. PLATENSE. The latter is the second SOLANUM with this unusual number. Satellites are always present and were visible in more than 50 % of the cells studied. Karyotypes are symmetrical: M and SM chromosomes are common, whereas ST chromosomes are rare. The karyotypes of S. AENICTUM, S. MAMMOSUM, and S. PANICULATUM are comparatively asymmetrical. Species can be distinguished by a combination of chromosome number, karyotype formulae, karyotype length, the position of satellites in a particular chromosome pair, and asymmetry indices. The phenogram obtained does not reflect the sectional arrangements or the systematic affinities of the species studied. In sect. ACANTHOPHORA, increased asymmetry is associated with derived characters (strong andromonoecy, winged seeds, mammiform fruits). Diversification in the subgenus is suggested to be related to visible chromosome rearrangements and cumulative, cryptic structural changes may have also played a relevant evolutionary role.
Biological Evolution↗
Chromosome banding pattern conservatism in birds and nonhomology of chromosome banding patterns between birds, turtles, snakes and amphibians.
The G-banded karyotypes of 4 species of birds representing the orders Galliformes, Columbiformes and Musophagiformes were compared. Banding pattern homology between orders was limited t 5o 5 major chromosome arms and the Z chromosome. Even in these major chromosome arms pericentric and paracentric inversions produced alteration of the banding pattern sequences. Addition of constitutive heterochromatin was responsible for changes in banding patterns in the Z chromosome. The chromosome banding patterns of an emydid turtle, Terrepene carolina, 5 species of boid snakes of the genera Liasis, Acrantophis, and Sanzinia and the African clawed-frog. Xenopus muelleri, were also compared to the bird chromosome banding patterns. No homology was observed between any of these major groups: bird, snake, turtle, amphibian. However, intergroup homology was apparent. - The data obtained do not support reports of broad interordinal direct homology of the macrochromosomes of birds and refutes the idea of a primitive bird karyotype with 3 pairs of "Agroup' chromosomes and 3 pairs of "B group' chromosomes. - The major mechanisms responsible for chromosome evolution in birds appear to be centric and tandem fusions, paracentric and pericentric inversions, and addition or deletion of heterochromatin.
Animals↗
[Karyotype analysis of 2 species of gibbons (Hylobates lar and H. concolor) with different banding species].
The mitotic chromosomes of two species of gibbons (Hylobates lar and H. concolor) are examined and compared, using various banding techniques. These two species have very different karyotypes. At the most, seven pairs of chromosomes have a similar banding pattern. The other elements generally differ by complex structrual rearrangements. Thus, it is difficult to propose a scheme for chromosomal evolution at this stage. Comparison with the karyotypes of man and anthropoid apes also shows very important differences; very few chromosomes are common or only slightly modified. Some considerations about the hypothetical origin of particular chromosomal structures are given.
Animals↗
Change in karyotype between diagnosis and first relapse in acute myelogenous leukemia.
We compared karyotype at first relapse with presenting karyotype in 212 patients with AML seen at MD Anderson Cancer Center (Houston, TX, USA) between 1975 and 1994. In 38% the karyotypes at diagnosis and relapse were identical. A stable karyotype was most frequent (70%) among patients who presented without cytogenetic abnormalities, suggesting that the finding of a normal karyotype is usually not due to sampling error. In contrast, a finding of insufficient metaphases at diagnosis was repeated at relapse in only 6% of cases. A change in karyotype occurred in 67% of 101 patients who presented with an abnormal karyotype and had sufficient metaphases for evaluation at relapse. The great majority of changes involved clonal evolution, clonal devolution (regression), or both; a purely normal karyotype and unrelated clones were seen in 11 and three of the 101, respectively. Change in karyotype between diagnosis and relapse and type of change were unrelated to remission duration. The only group in which karyotype at relapse vs that at diagnosis had a possible bearing on achievement of second CR were patients who presented with abnormalities other than inv(16), t(8;21) or t(15;17) and who at relapse had only normal metaphases; such patients had higher CR rates than comparable patients who retained their presenting abnormalities.
Chromosome Aberrations↗
Dog chromosome-specific paints reveal evolutionary inter- and intrachromosomal rearrangements in the American mink and human.
Forty chromosome-specific paint probes of the domestic dog (Canis familiaris, 2n = 78) were used to delineate conserved segments on metaphase chromosomes of the American mink (Mustela vison, 2n = 30) by fluorescence in situ hybridisation. Half of the 38 canine autosomal probes each painted one pair of homologous segments in a diploid mink metaphase, whereas the other 19 dog probes each painted from two to five pairs of discrete segments. In total, 38 canine autosomal paints highlighted 71 pairs of conserved segments in the mink. These painting results allow us to establish a complete comparative chromosome map between the American mink and domestic dog. This map demonstrates that extensive chromosome rearrangements differentiate the karyotypes of the dog and American mink. The 38 dog autosomes could be reconstructed from the 14 autosomes of the American mink through at least 47 fissions, 25 chromosome fusions, and six inversions. Furthermore, comparison of the current dog/mink map with the published human/dog map discloses 23 cryptic intrachromosomal rearrangements in 10 regions of conserved synteny in the human and American mink genomes and thus further refined the human/mink comparative genome map.
Animals↗
Reconstruction of the ancestral karyotype of eutherian mammals.
Applying the parsimony principle, i.e. that chromosomes identical in species belonging to different taxa were likely to be present in their common ancestor, the ancestral karyotype of eutherian mammals (about 100 million years old) was tentatively reconstructed. Comparing chromosome banding with all ZOO-FISH data from literature or studied by us, this reconstruction can be proposed with only limited uncertainties. This karyotype comprised 50 chromosomes of which 40-42 were acrocentrics. Ten ancestral pairs of chromosomes were homologous to a single human chromosome: 5, 6, 9, 11, 13, 17, 18, 20, X and Y (human nomenclature). Nine others were homologous to a part of a human chromosome: 1p + q (proximal), 1q, 2p + q (proximal), 2q, part of 7, 8q, 10p, 10q and 19p (human nomenclature). Finally, seven pairs of chromosomes, homologs to human chromosomes 3 + 21, 4 + 8p, part of 7 + 16p, part of 12 + part of 22 (twice), 14 + 15, 16q + 19q, formed syntenies disrupted in man.
Animals↗
Chromosomal studies in Callicebus donacophilus pallescens, with classic and molecular cytogenetic approaches: multicolour FISH using human and Saguinus oedipus painting probes.
This paper presents the karyotype of Callicebus donacophilus pallescens for the first time. The analysis included G-, C-, NOR-banding techniques and FISH with chromosome painting probes from Saguinus oedipus and Homo sapiens. The results were compared with the karyotypes of Callicebus moloch donacophilus and C. moloch previously published. These three karyotypes display the same diploid number (2n = 50) but diverge about the number of biarmed and acrocentric chromosomes. The acrocentrics 14 and 15 from C. m. donacophilus and C. moloch have undergone an in-tandem fusion originating a large acrocentric (pair 10) in C. d. pallescens. The major submetacentric pair (pair 1) from C. d. donacophilus and C. moloch have undergone fission originating two acrocentric pairs in C. d. pallescens (pairs 15 and 22). Herein was evidence that, in spite of the high interspecific variation among Callicebus, most of the chromosomes remained conserved.
Animals↗
Massive cytogenetic heterogeneity in a pancreatic carcinoma: fifty-four karyotypically unrelated clones.
Chromosome analysis after short-term culture revealed remarkable cytogenetic heterogeneity in a pancreatic carcinoma. The patient had no prior history of radio- or chemotherapy. A total of 54 aberrant, near-diploid, karyotypically unrelated clones were identified, three of which displayed clonal evolution. The abnormalities were unbalanced in 30% of the clones. From one to eight karyotypic anomalies per clone were found. Numerical changes were rare, whereas structural aberrations were numerous and diverse and included deletions, duplication, insertions, inversions, translocations, ring formation, and telomeric associations. All chromosomes except No. 15 were involved in structural rearrangements, chromosomes 1, 6, 7, 8, 11, and 12 being the most frequently affected. A similarly massive cytogenetic polyclonality has never been reported previously. Although the spectrum of epithelial neoplasms characterized by karyotypically unrelated clones is increasing, the pathogenetic role of this type of cytogenetic intratumor heterogeneity remains unknown.
Aged↗
Molecular epidemiology and diagnosis of Leishmania: what have we learnt from genome structure, dynamics and function?
This paper reviews our exploration of the dynamics of the Leishmania genome and its contribution to epidemiology and diagnosis. We used as a model Peruvian populations of L. (Viannia) braziliensis and L. (V.) peruviana, 2 species very close phylogenetically, but phenotypically very different in biotope and pathology. We initially focused on karyotype analysis. Our data showed that chromosomes were subject to a fast rate of evolution, and were sensitive indicators of genetic drift. Therefore, molecular karyotyping appeared an adequate tool for monitoring (i) emergence of close species, (ii) ecogeographical differentiation at the intraspecific level, and (iii) strain 'fingerprinting'. Chromosome size variation was mostly due to the number of tandemly repeated genes (rDNA, mini-exon, gp63, and cysteine proteinase genes), and could involve the deletion of unique genes (L. (V.) braziliensis-specific gp63 families). Considering the importance of these genes in parasitism, their rearrangement might have functional implications: adaptation to different environments and pleomorphic pathogenicity. Our knowledge of genome structure and dynamics was used to develop new polymerase chain reaction (PCR) techniques. Amplification of gp63 genes followed by cleavage with restriction enzymes and study of restriction fragment length polymorphism (gp63 PCR-RFLP) allowed the discrimination of all species tested, even directly in biopsies with 95% sensitivity (compared with PCR amplification of kinetoplast deoxyribonucleic acid). At the intra-specific level, RFLP was also observed and corresponded to mutations in major immunogen domains of gp63. These seem to be under strong selection pressure, and the technique should facilitate addressing how the host's immune pressure may modulate parasite population structure. Altogether, gp63 PCR-RFLP represents a significant operational improvement over the other techniques for molecular epidemiology and diagnosis: it combines sensitivity, discriminatory power and prognostic value.
Animals↗
Molecular characterisation of the pericentric inversion that distinguishes human chromosome 5 from the homologous chimpanzee chromosome.
Human and chimpanzee karyotypes differ by virtue of nine pericentric inversions that serve to distinguish human chromosomes 1, 4, 5, 9, 12, 15, 16, 17, and 18 from their chimpanzee orthologues. In this study, we have analysed the breakpoints of the pericentric inversion characteristic of chimpanzee chromosome 4, the homologue of human chromosome 5. Breakpoint-spanning BAC clones were identified from both the human and chimpanzee genomes by fluorescence in situ hybridisation, and the precise locations of the breakpoints were determined by sequence comparisons. In stark contrast to some other characterised evolutionary rearrangements in primates, this chimpanzee-specific inversion appears not to have been mediated by either gross segmental duplications or low-copy repeats, although micro-duplications were found adjacent to the breakpoints. However, alternating purine-pyrimidine (RY) tracts were detected at the breakpoints, and such sequences are known to adopt non-B DNA conformations that are capable of triggering DNA breakage and genomic rearrangements. Comparison of the breakpoint region of human chromosome 5q15 with the orthologous regions of the chicken, mouse, and rat genomes, revealed similar but non-identical syntenic disruptions in all three species. The clustering of evolutionary breakpoints within this chromosomal region, together with the presence of multiple pathological breakpoints in the vicinity of both 5p15 and 5q15, is consistent with the non-random model of chromosomal evolution and suggests that these regions may well possess intrinsic features that have served to mediate a variety of genomic rearrangements, including the pericentric inversion in chimpanzee chromosome 4.
Animals↗
Deletion 6p23 and add(11)(p15) leading to NUP98 translocation in a case of therapy-related atypical chronic myelocytic leukemia transforming to acute myelocytic leukemia.
A NUP98 gene translocation occurring with a del(6p23) and an add(11)(p15) was determined in a 61-year-old patient with therapy-related atypical chronic myelocytic leukemia after complete remission from acute promyelocytic leukemia that eventually underwent clonal evolution and transformed to CD56-positive acute myelocytic leukemia (French-American-British classification M0). Precise chromosome analysis by G-banding, spectral karyotyping analysis, and dual-color fluorescence in situ hybridization showed this abnormality as 46,XY,del(6)(p23),add(p15). ish del(6)(NUP98-,D6Z1+),der(7)(NUP98+,D7Z1+),der(11)(NUP98+,D11Z1). A split signal of NUP98 was observed in 68.4% of the 117 cells analyzed, which clearly indicated that the NUP98 partially translocated to chromosome 7. However, the potential fusion partner of the NUP98 was not HOX family or DEK. The fusion gene has not been found by a differential display method. The significance of simultaneously combined del(6)(p23), which also has been reported with secondary leukemogenesis, has not been elucidated. Additional karyotype abnormalities evolved increasingly, and leukocytosis with blasts with more complex karyotypic abnormalities appeared 5 months later. Careful and continuous analysis of karyotype change clarified the process of the clonal evolution after NUP98 translocation. Further investigation of molecular characterization of this NUP98 translocation and interaction with 6p23 abnormalities might be worthwhile for understanding leukemogenesis.
Chromosome Deletion↗
Genome evolution in the mosquitoes and other closely related members of superfamily Culicoidea.
Karyotypes and nuclear DNA amounts of 36 species belonging to twelve genera of mosquitoes and other closely related taxa in the superfamily Culicoidea (Dixidae, Chaoboridae, and Culicidae) were studied. The results showed an eight-fold range in haploid DNA amounts and a 4.5-fold range in total chromosomal lengths. It is concluded that the evolutionary trend in this superfamily has been an overall increase in total haploid DNA amounts from the primitive Dixidae to the highly evolved Culcidae, with a concomitant increase in overall chromosome sizes.
Animals↗
Ataxia telangiectasia with evolution of monosomy 14 and emergence of Hodgkin's disease.
A young woman, with ataxia telangiectasia (AT) had a chromosomally abnormal T-lymphocyte clone detected at 23 years of age. This clone showed nonrandom loss of chromosome # 14, a karyotypic abnormality not previously described in AT. Eighteen months later, evolution of the monosomic clone was noted; the karyotype of this latter clone was 45,XX,-14,del(6) (q21). The patient died of Hodgkin's disease of mixed cellularity type, Stage IIIB, a few months later. A striking histological features of a lymph node biopsy was the presence of numerous epithelioid histiocytes. The patient's paternal first cousin also suffers from AT.
Adult↗
The evolution of heteromorphic sex chromosomes.
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Animals↗
Leukemia characterized by multiple sub-clones with unbalanced translocations involving different telomeric segments: case report and review of the literature.
A 68-year-old man presented with t(4;11)(q21;q23), B-lineage acute lymphoblastic leukemia (ALL) which was negative for C-ALL antigen and TdT. Clonal evolution to five different, but related karyotypes, in which chromosomal material distal either to 1q11 or 1q21 was translocated to the terminal regions of 4q-, 11q, 16q, and 19p resulted in partial or total trisomy of 1q. The patient, having achieved a short remission, died 14 weeks after diagnosis. Five reports of jumping translocations in hematological malignancies, four with B-lineage malignancy, are reviewed. One (four cases) or both (one case) of the same 1q breakpoints were consistently found and 11q and 16q were repeatedly involved. Such cases, having multiple subclones with trisomy 1q, may form a distinct subgroup of ALL.
Aged↗
Chromosomes of Syrphidae. IV. Karyotypes of fourteen species in the tribe Chrysotoxini.
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Animals↗