Teses em Neurociências e Biologia Celular (Doutorado) - PPGNBC/ICB

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2390

O Doutorado Acadêmico pertence ao Programa de Pós-Graduação em Neurociências e Biologia Celular (PPGNBC) do Instituto de Ciências Biológicas (ICB) da Universidade Federal do Pará (UFPA).

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    Aplicação de pintura cromossômica em espécies da família Accipitridae (Aves, Falconiformes): considerações filogenéticas e evolutivas
    (Universidade Federal do Pará, 2013-10-18) TAGLIARINI, Marcella Mergulhão; OLIVEIRA, Edivaldo Herculano Correa de; http://lattes.cnpq.br/0094007714707651
    Cytogenetic analyses of Falconiformes have showed that Accipitridae have atypical chromosomal organization among birds, with relatively low diploid numbers (mean of 2n=66) and a few pairs of microchromosomes (4 to 6 pairs). Proposals based on classical cytogenetics suggested that this fact was a result of fusions of microchromosomes found in the Avian putative ancestor karyotype. With the aim of contributing to clarify questions concerning chromosomal evolution and phylogenetics of this family, we analyzed three species of subfamily Buteoninae (Rupornis magnirostris, Buteogallus meridionales e Asturina nítida) and two of subfamily Harpiinae (Harpia harpyja e Morphnus guianensis) by means of classical and molecular cytogenetics. Buteoninae species showed karyotypes with diploid number 68 and FN varying from 100 to 102; the number of biarmed chromosomes varied between 17 and 21, Z chromosome was submetacentric and W chromosome was metacentric in R. magnirostris and submetacentric in Asturina nitida. 18/28 rDNA probes showed that nucleolar organizer regions are located in a medium-sized submetacentric pair, corresponding to the short arm of pair 7. Telomeric sequences were found not only on terminal region of the chromosomes, but also on some interstitial regions. Whole-chromosome paints derived from pairs 1 to 11 of Gallus gallus (GGA) produced the same number of signals in these species. The availability of whole-chromosome probes derived of Leucopternis albicollis confirmed the presence of a common cytogenetic signature for Buteoninae species, corresponding to the association between GGA1p and GGA6. An interstitital telomeric sequence found in this pair reinforces this fact. Concerning the species of Harpiinae, the conventional staining analyses showed that H. harpyja and M. guianensis have 2n=58 and 2n=56, respectively. Both species have 22 pairs of biarmed chromosomes, although H. harpyja has two more chromosomes than M. guianensis. 18/28S rDNA mapped on the short arm of pair 1 in M. guianensis and in two pairs in H, harpyja (6 and 25). Telomeric sequences were found on the terminal regions, but also on interstitial locations in some chromosomes. Despite the apparent karyotypic similarity, no common associations were found in these two species. The different associations observed in Morphnus and Harpia indicate that these species suffered an extensive genomic reorganization after their separation in two independent lineages. Moreover, the absence of shared associations suggests that the fissions of macrochromosomes have occurred in the common ancestor of this group, and that fusions were subsequent to their isolation as different lineages. Our results, together with previous reports in other species of Accipitridae, indicate that the processes of fissions involving the macrochromosomes of GGA and fusions between these segments and between them and microchromosomes are recurrent rearrangements in this group. Although Falconidae species also show atypical karyotypes, with low diploid numbers, global cytogenetic data of Accipitridae indicate that, similarly to the morphological traits between these two families, the rearranged karyotypes would correspond to homoplasies, from the evolutionary point of view, supporting the idea that these families do not form a monophyletic group.
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    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.
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