Navegando por Assunto "Cromossomos"

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Acesso aberto (Open Access)
Análise citogenética em morcegos da família Emballonuridae (Chiroptera) da Amazônia Brasileira através de citogenética clássica e molecular
(Universidade Federal do Pará, 2011-04-29) ARAÚJO, Ramon Everton Ferreira de; PIECZARKA, Julio Cesar; http://lattes.cnpq.br/6644368250823351
This is the first description of the karyotypes of bats of the family Emballonuridae from the Brazilian Amazon region. The species studied were Cormura brevirostris-CBR (2n=22; NF=40), Rhynchonycteris naso-RNA (2n=22 and NF=36), Saccopteryx canescens-SCA (2n=24 and FN=38) and Saccopteryx leptura-SLE (2n=28 and NF=38), characterized by G-, C-banding, NOR-staining and Fluorescent In Situ Hybridization (FISH). In CBR the karyotypes found had the same diploid number and fundamental number than in literature. FISH with ribosomal DNA probes and Ag-NOR staining showed two NOR places. Hybridization with telomeric probes showed that the sequences were found in the centromeres of all chromosomes but the Y. Using meiotic studies, chromosome banding and FISH with a whole X chromosome probe from Phyllostomus hastatus (Chiroptera, Phyllostomidae) we suggest that the sex chromosome pair of this species is not the one described in the literature. Cells in diploid and diakinesis had a ring conformation with four chromosome pairs, what suggests multiple reciprocal translocations among these chromosomes, a very rare situation in vertebrates and never found in eutherian mammals. The analyses of RNA, SCA and SLE shows that the karyotypes of Emballonuridae are very conservative even when compared with samples collected geographically very far, but the C-banding analyses shows that it can happen intraspecific variations in the constitutive heterochromatin. For the first time the Nucleolar Organizer Regions were described, showing a stained pair of chromosomes on each analyzed species. The FISH with 18S rDNA probes agrees with the Ag-NOR staining. FISH with human telomeric probes showed hybridizations in the distal portion of all chromosomes. These works are Important to understand the biodiversity of bats from the Amazon region, as well as the comprehension of the chromosomal evolution of Chiroptera.
Acesso aberto (Open Access)
Caracterização cromossômica e mapeamento genômico comparativo de Oecomys paricola e Oecomys auyantepui com sondas de Hylaeamys megacephalus (Cricetidae – Sigmodontinae)
(Universidade Federal do Pará, 2015-05-19) ROSA, Celina Coelho da; NAGAMACHI, Cleusa Yoshiko; http://lattes.cnpq.br/8887641213110093
The Order Rodentia represents the largest mammal order, with approximately 42% of species currently known. Rodents have 2,227 species, 468 genera and 33 families recent, the latter being raised to 50 if the extinct families are considered. Their huge variation in morphology, diversity of habitats and climates and food are the causes of this be most numerous and evolutionarily successful among mammalian orders. The Oecomys genus belongs to the subfamily Sigmodontinae (Cricetidae, Rodentia) with approximately 16 described species, distributed in tropical and subtropical forest of Central and South America. Previous cytogenetic studies suggest that Oecomys features large karyotype diversity, with the diploid number ranging from 58 to 86. In this study were analyzed by conventional cytogenetic techniques and multidirectional chromosome painting (using whole chromosome probes of Hylaeamys megacephalus) 18 specimens of Oecomys were analyzed, four were collected in the metropolitan area of Belém, Pará; two in the city of Santa Barbara, Pará; five in the region of Carajás, Pará and 7 in Calha Norte region, Pará. Specimes from Belém Environmental Park had 2n = 72 and FN = 76; specimes from Santa Barbara had 2n = 70 and FN = 74; from Carajás presented 2n = 70 and FN = 72. All this sample was identified as O. paricola. Specimens collected from the Calha Norte region had 2n = 62 and NF = 80 and were identified as O. auyantepui. The cytotypes described for O. paricola showed differences in five HME peaks, indicating 3 associations for this species. O. auyantepui showed five associations. Chromosomal differences found for O. paricola from different geographic regions suggest that these cytotypes belong to cryptic species. We suggest that these populations of O. paricola are a complex of species where the chromosomal differentiation already happened but not the morphological and molecular ones.
Acesso aberto (Open Access)
Comparação cromossômica intrapopulacional da espécie Tayassu tajacu criada em cativeiro
(Universidade Federal do Pará, 2005-04-13) SOUZA, Patrícia Carvalho de; BURBANO, Rommel Mario Rodriguéz; http://lattes.cnpq.br/4362051219348099
The collared peccary (Tayassu tajacu) is found from southern United States to northern Argentina. In Brazil, it ranges all over the country and is a source of meat for local people. Thus, a cytogenetic analysis is an important tool to evaluate reproductive efficiency at animals breeding in captivity that in order to commercialization. The aim of this study was to determine the chromosomal number of this specie from animals breeding in captivity of different populations. The animals utilized in this work were from different Brazilian populations: 6 animals from Mossoró (RN), 1 from Ipixuna (PA) and 4 from Uruará (PA). Metaphase chromosomes were prepared from cultured blood lymphocytes, following standard procedures. The results showed the same karyotypic pattern found for others authors (2n = 30 chromosomes and FN = 48), although, not any differences were found among these populations. But, they showed the same South American pattern, however, chromosomal polymorphism were found when compared to others populations, in Brazil and others countries (United States and French Guiana).
Acesso aberto (Open Access)
Karyotypic analysis in species of the genus Dasyprocta (Rodentia: Dasyproctidae) found in Brazilian Amazon
(2003-03) RAMOS, Rosemar Silva Luz; VALE, William Gomes; ASSIS, Maria de Fátima Lima
A total of 30 animals of the genus Dasyprocta were cytogenetically studied. They belong to the following species: D. prymnolopha (N=20), D. leporina (N=6), D. fuliginosa (N=1) and Dasyprocta sp. (N=3) (Dasyproctidae, Hystricognathi). Cell suspensions were obtained by peripheral blood culture, besides bone marrow and spleen cells, from D. prymnolopha and D. leporina. The diploid number was 64/65 for all samples. The karyotypes showed similarity, and chromosomal polymorphism was not detected by Giemsa conventional staining and G banding. The constitutive heterochromatin distribution at the pericentromeric region of all the chromosomes was similar in all species. D. prymnolopha, D. leporina and Dasyprocta sp. presented variation in the heterochromatical block size at one of the homologues of the A18 pair. D. fuliginosa presented the heterochromatin uniformly distributed in all chromosomes. There was not variation in the NORs pattern in the species studied.
Acesso aberto (Open Access)
The karyotype of Alouatta fusca clamitans from Rio de Janeiro, Brazil: Evidence for a y-autosome translocation
(1998-09) OLIVEIRA, Edivaldo Herculano Correa de; LIMA, Margarida Maria Celeira de; SBALQUEIRO, Ives José; PISSINATTI, Alcides
The chromosome complements of four males of Alouatta fusca clamitans, caught in Rio de Janeiro State, Brazil, were analyzed by G-, C-, and NOR-banding techniques. The diploid number found was 49 in all the specimens. The presence of a heteromorphic pair of submetacentric chromosomes in the analyzed specimens, not present in males and females with 2n = 50 previously reported, and its G-banding pattern, led us to assume that this pair is involved in a Y-autosome translocation. Thus, the sex determination system appears modified to X1X1X2X2 /X1X2Y. Heterochromatic segments were found in the pericentromeric region of all the chromosomes, in the telomeric region of the short arm in pair 2, in the complete length of the short arm of pairs 5 and 6 and in the intercalary region of the long arm in pair 17. The nucleolar organizer regions were situated in the intercalary region of the long arm in two small acrocentric pairs.