Chromosome evolution

Intraspecific and interspecific polyploidy of Brazilian species of the genus Inga (Leguminosae: Mimosoideae)

M. F. Figueiredo, Bruno, R. L. A., Silva, A. E. Barros e, Nascimento, S., Oliveira, I. G., and Felix, L. P., “Intraspecific and interspecific polyploidy of Brazilian species of the genus Inga (Leguminosae: Mimosoideae)”, vol. 13, pp. 3395-3403, 2014.

We investigated the karyotypes of 13 species of six sections of the genus Inga (Leguminosae-Mimosoideae) from Brazil. We used conventional Giemsa staining to identify numerical chromosomal variations and looked for karyotypic evolutionary patterns. The karyotypes generally had small chromosomes, varying from metacentric to submetacentric, with a basic number x = 13. Nine of the species showed 2n = 2x = 26 (I. thibaudiana, I. cayennensis, I. ingoides, I. edulis, I. vera, I. subnuda, I. striata, I.

Is there a relationship between polyploidy and stressful environments? A case study of inselbergs in northeastern Brazil

S. R. Pitrez, Andrade, L. A., Assis, F. N. M., and Felix, L. P., “Is there a relationship between polyploidy and stressful environments? A case study of inselbergs in northeastern Brazil”, vol. 13, pp. 8353-8366, 2014.

The aim of this study was to examine the hypothesis that plants with higher ploidy levels are selected by environments under more extremely stressful conditions than the same (or closely related) species from less rigorous terrestrial or epiphytic habitats. Therefore, we analyzed the chromosome numbers of 26 species belonging to 21 genera and 13 families of angiosperms that were collected on 4 inselbergs in Paraiba State, northeastern Brazil.

Evolutionary dynamics of rDNA genes on chromosomes of the Eucinostomus fishes: cytotaxonomic and karyoevolutive implications

L. L. Calado, Bertollo, L. A. C., Cioffi, M. B., Costa, G. W. W. F., Jacobina, U. P., and Molina, W. F., “Evolutionary dynamics of rDNA genes on chromosomes of the Eucinostomus fishes: cytotaxonomic and karyoevolutive implications”, vol. 13, pp. 9951-9959, 2014.

Several chromosomal features of Gerreidae fish have been found to be conserved. In this group, it is unclear whether the high degree of chromosomal stasis is maintained when analyzing more dynamic regions of chromosomes, such as rDNA sites that generally show a higher level of variability. Thus, cytogenetic analyses were performed on 3 Atlantic species of the genus Eucinostomus using conventional banding (C-banding, Ag-NOR), AT- and GC-specific fluorochromes, and fluorescence in situ hybridization mapping of telomeric sequences and 5S and 18S rDNA sites.

Philadelphia-negative chromosomal evolution during treatment for chronic myeloid leukemia

H. - H. Hsiao, Liu, Y. - C., Lee, C. - P., Chang, C. - S., and Lin, S. - F., “Philadelphia-negative chromosomal evolution during treatment for chronic myeloid leukemia”, vol. 11, pp. 317-321, 2012.

Chromosome evolution is one of the major mechanisms of disease progression and resistance in chronic myeloid leukemia (CML) patients. However, the clinical significance of chromosomal evolution in the Philadelphia (Ph)-negative clone during therapy is not fully understood. We evaluated 94 CML patients in the chronic phase of CML during treatment of the disease. Six of them had Ph-negative chromosome abnormalities during treatment.

Chromosomal diversity in Hypostomus (Siluriformes, Loricariidae) with emphasis on physical mapping of 18S and 5S rDNA sites

J. B. Traldi, Blanco, D. R., Vicari, M. R., Martinez, J. F., Lui, R. L., Barros, A. V., Artoni, R. F., and Moreira-Filho, O., “Chromosomal diversity in Hypostomus (Siluriformes, Loricariidae) with emphasis on physical mapping of 18S and 5S rDNA sites”, vol. 12, pp. 463-471, 2013.

We examined chromosomes of three species of the genus Hypostomus, in order to contribute to the understanding of the karyotype evolution of this group. Specimens of H. ancistroides and H. nigromaculatus displayed differences in karyotype formulas, distribution and location of heterochromatin and nucleolus organizer regions when compared to other populations of the same species. We made the first cytogenetic characterization of H. tapijara, an endemic species in the Ribeira de Iguape River. These specimens had 2n = 66 chromosomes, while H.

Chromosomal characteristics of a Brazilian whip spider (Amblypygi) and evolutionary relationships with other arachnid orders

E. Paula-Neto, Araujo, D., Carvalho, L. S., Cella, D. M., and Schneider, M. C., “Chromosomal characteristics of a Brazilian whip spider (Amblypygi) and evolutionary relationships with other arachnid orders”, vol. 12, pp. 3726-3734, 2013.

We analyzed mitotic and meiotic cells of a Brazilian amblypygid, Heterophrynus longicornis, using conventional and molecular cytogenetic techniques (Giemsa staining, C-banding, Ag-NOR, and FISH with rDNA probe). This is the first study that focuses solely on amblypygid chromosomes; it was undertaken to add data on cytogenetic knowledge of this group and contribute to the understanding of chromosome evolution in the Arachnida. We found 2n = 66 for male and female individuals, monocentric chromosomes, and absence of morphologically differentiated sex chromosomes.

Different responses to doxorubicin-induced chromosome aberrations in Brazilian deer species

D. S. F. Vargas-Munar, Sarria-Perea, J. A., and Duarte, J. M. B., “Different responses to doxorubicin-induced chromosome aberrations in Brazilian deer species”, vol. 9, pp. 1545-1549, 2010.

The tendency toward chromosome fragility is one of the theories that may explain chromosome variation in brocket deer species (genus Mazama). We tested doxorubicin as an inducer of chromosome aberrations in lymphocytes of three brocket deer species, Mazama gouazoubira, M. americana and M. nana, compared to the marsh deer, Blastocerus dichotomus. Doxorubicin, at a concentration of 0.25 μg/mL, induced chromosome aberrations and fragile sites in all four species; the highest frequencies were seen in M.

Heterochromatin and chromosome evolution: a FISH probe of Cebus apella paraguayanus (Primate: Platyrrhini) developed by chromosome microdissection

M. Nieves, Mühlmann, M., Mühlmann, M., and Mudry, M. Dolores, “Heterochromatin and chromosome evolution: a FISH probe of Cebus apella paraguayanus (Primate: Platyrrhini) developed by chromosome microdissection”, vol. 4, pp. 675-683, 2005.

Neotropical Primate karyotypes are highly variable, particularly in the heterochromatic regions, not only regarding the amount of heterochromatin, but also the composition. G and C banding and FISH techniques provide useful information to characterize interspecific relationships. We used chromosome microdissection to develop a FISH probe of the chromosome 11 heterochromatic block (11qHe+) of Cebus apella paraguayanus (CAPp).

Karyotypic studies of Cratylia argentea (Desv.) O. Kuntze and C. mollis Mart. ex Benth. (Fabaceae - Papilionoideae)

S. M. Vargas, Torres, G. A., Sobrinho, F. S., Pereira, A. V., and Davide, L. C., “Karyotypic studies of Cratylia argentea (Desv.) O. Kuntze and C. mollis Mart. ex Benth. (Fabaceae - Papilionoideae)”, vol. 6, pp. 707-712, 2007.

Cratylia argentea and C. mollis (Fabaceae-Papilionoideae) are legume shrubs native to the Cerrado and Caatinga, respectively. Both species show great resistance to drought and high nutritive value, which makes them a valuable forage resource in tropical regions. Cytogenetic studies were carried out on accessions of C. argentea and C. mollis from Germplasm Banks of Embrapa Gado de Leite (Juiz de Fora, MG) and Embrapa Semi-Árido (Petrolina, PE), respectively.

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