Navegando por Autor "OLIVEIRA, Edivaldo Herculano Correa de"

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Acesso aberto (Open Access)
Karyotypic evolution of ribosomal sites in buffalo subspecies and their crossbreed
(2014-06) DEGRANDI, Tiago Marafiga; PITA, Sebastian; PANZERA, Yanina; OLIVEIRA, Edivaldo Herculano Correa de; MARQUES, José Ribamar Felipe; FIGUEIRÓ, Marivaldo Rodrigues; MARQUES, Larissa Coelho; VINADE, Lucia Helena do Canto; GUNSKI, Ricardo José; DEL VALLE GARNERO, Analía
Domestic buffaloes are divided into two group based on cytogenetic characteristics and habitats: the “river buffaloes” with 2n = 50 and the “swamp buffaloes”, 2n = 48. Nevertheless, their hybrids are viable, fertile and identified by a 2n = 49. In order to have a better characterization of these different cytotypes of buffaloes, and considering that NOR-bearing chromosomes are involved in the rearrangements responsible for the karyotypic differences, we applied silver staining (Ag-NOR) and performed fluorescent in situ hybridization (FISH) experiments using 18S rDNA as probe. Metaphases were obtained through blood lymphocyte culture of 21 individuals, including river, swamp and hybrid cytotypes. Ag-NOR staining revealed active NORs on six chromosome pairs (3p, 4p, 6, 21, 23, 24) in the river buffaloes, whereas the swamp buffaloes presented only five NOR-bearing pairs (4p, 6, 20, 22, 23). The F1 crossbreed had 11 chromosomes with active NORs, indicating expression of both parental chromosomes. FISH analysis confirmed the numerical divergence identified with Ag-NOR. This result is explained by the loss of the NOR located on chromosome 4p in the river buffalo, which is involved in the tandem fusion with chromosome 9 in this subspecies. A comparison with the ancestral cattle karyotype suggests that the NOR found on the 3p of the river buffalo may have originated from a duplication of ribosomal genes, resulting in the formation of new NOR sites in this subspecies.
Acesso aberto (Open Access)
Maintenance of syntenic groups between Cathartidae and Gallus gallus indicates symplesiomorphic karyotypes in new world vultures
(2011) TAGLIARINI, Marcella Mergulhão; O'BRIEN, Patricia C.M.; FERGUSON-SMITH, Malcolm A.; OLIVEIRA, Edivaldo Herculano Correa de
Similarities between New World and Old World vultures have been interpreted to reflect a close relationship and to suggest the inclusion of both in Accipitridae (Falconiformes). However, deeper analyses indicated that the placement of the New World vultures (cathartids) in this Order is uncertain. Chromosome analysis has shown that cathartids retained a karyotype similar to the putative avian ancestor. In order to verify the occurrence of intrachromosomal rearrangements in cathartids, we hybridized whole chromosome probes of two species (Gallus gallus and Leucopternis albicollis) onto metaphases of Cathartes aura. The results showed that not only were the syntenic groups conserved between Gallus and C. aura, but probably also the general gene order, suggesting that New World vultures share chromosomal symplesiomorphies with most bird lineages.
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.