|
|
|
|
| |
|
| |
|
|
| Hashimoto,Diogo Teruo; Gonçalves,Vanessa Regina; Bortolozzi,Jehud; Foresti,Fausto; Porto-Foresti,Fábio. |
| Several species of the genus Astyanax have already been genetically studied, and B-chromosomes have been considered to be an interesting feature in some species of this group. In the present paper we report, for the first time, the occurrence of a B microchromosome in a natural population of A. altiparanae. This additional genomic element was identified as an acrocentric chromosome, similar in size to the smallest chromosomal pairs of the standard karyotype. Analysis of the constitutive heterochromatin pattern by C-banding evidenced heterochromatic blocks located on centromeric, pericentromeric, and interstitial regions of some chromosomes, and also positive marks in a subtelocentric chromosomal pair that presented the short arms entirely heterochromatic.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: B chromosomes; Fish cytogenetics; Astyanax altiparanae. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000200021 |
| |
|
|
| Santos,Lessandra Viviane De Rosa; Foresti,Fausto; Martins,Cesar; Oliveira,Claudio; Wasko,Adriane Pinto. |
| Cytogenetic analyses were performed in Cyphocharax modestus, collected at Paranapanema River and Tietê River (São Paulo State, Brazil). A karyotype with 2n = 54 chromosomes was observed in the animals from both Brazilian freshwater river systems. One to four B chromosomes were also detected in individuals from the Paranapanema River, which represents the probable first report of more than a single supernumerary element in a species of the Curimatidae group. C-banding revealed centromeric and telomeric heterochromatin blocks in several chromosomes of the normal karyotype complement of C. modestus. Moreover, while some B chromosomes were characterized by the complete absence of C-bands, others were totally heterochromatic. Although there was a prevalence of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: B chromosomes; C-banding; Curimatidae; Cyphocharax modestus; Supernumerary chromosomes. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000200019 |
| |
|
|
| Felix,Winston J. P.; Dutilh,Julie H. A.; Melo,Natoniel F. de; Fernandes,Andrea A.; Felix,Leonardo P.. |
| Zephyranthes Herb. is a taxonomically complex and cytologically variable group, with about 65 species of Neotropical distribution. Chromosome number variability in 32 individuals of a Zephyranthes sylvatica population from Northeast Brazil was investigated. Three cytotypes were found: 2n = 12 (one metacentric, four submetacentric and one acrocentric pairs), in 24 individuals; 2n = 12 + 1B, in five and three individuals with 2n = 18, a triploid cytotype. All diploid individuals showed chromosomes with polymorphism in pair one and two, while in triploids this polymorphism was observed in all chromosome triplets, generally with two homomorphic chromosomes and a higher or lower heteromorphic chromosome. All individuals had reticulated interfasic nucleus and a... |
| Tipo: Info:eu-repo/semantics/report |
Palavras-chave: Amaryllidaceae; B chromosomes; Chromosome variability; Triploid; Zephyranthes. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042008000200020 |
| |
|
|
| Barth,Adriane; Fernandes,Anderson; Pompolo,Silvia das Graças; Costa,Marco Antônio. |
| Tetragonisca angustula and Tetragonisca fiebrigi have recently been listed as valid species. This study aimed to cytogenetically investigate both species, emphasizing the new registry of B chromosomes in the tribe Meliponini. We analyzed colonies of T. angustula and T. fiebrigi collected at Tangará da Serra, Mato Grosso, Brazil, through conventional Giemsa staining, C-banding, and base-specific fluorochrome staining (CMA3/DAPI). T. angustula showed 2n = 34 chromosomes in females and n = 17 in males, with karyotype formula 2K = 34A M. T. fiebrigi showed numeric variation, with chromosome number varying from 2n = 34 to 2n = 36 in females and from n = 17 to n=18in males, with karyotype formula 2K = 32A M+2A Mc and 2K = 32A M+2A Mc + 1 or 2 B-chromosomes. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Stingless bees; Cytogenetics; Interspecific differentiation; B chromosomes. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572011000100014 |
| |
|
| |
|
|
|
