IDENTIFICATION OF COMMON FRAGILE SITES IN CHROMOSOMES OF 2 SPECIES OF BAT (CHIROPTERA, MAMMALIA)

In the karyotypes of the bat species Molossus ater and M molossus, spontaneous and bromodeoxyuridine (BrdU)- or aphidicolin (APC)-sensitive fragile sites were located. Four chromosome regions harbored APC-sensitive fragile sites: 1q9 and 8q4 in both M ater and M molossus, 3q3 in M ater, and 1p7 in M molossus. The fragile sites in 1q9 and 8q4 were also observed without induction in M molossus. BrdU-sensitive fragile sites were not detected. Despite observations in several other species, the fragile sites detected in Molossus are not coincident with the breakpoints involved in the chromosome rearrangements occurring in the evolution of 7 species of the Molossidae family.

Cytogenetic studies on holocentric chromosomes of five species of triatomines (Heteroptera: Reduviidae)

The chromosome number and meiotic cycle of triatomines were investigated. All five species presented the same diploid chromosome number, 2n = 22 (20A + XY in the male). Phylogenetic relationships based on chromosomal evidence and C-banded karyotypes in the subfamily are discussed. It is suggested that differences in DNA content are mainly due to variations in the amount of C-heterochromatin, which may be interpreted as loss and/or gain of C-regions. This interpretation is supported by the presence of meiotic and mitotic chromocentres which facilitate the transfer of C-positive material.

RH maps of bovine chromosomes 15 and 29: conservation of human chromosomes 11 and 5

Comparative mapping data on evolutionary conserved coding sequences and synteny maps between human and cattle are insufficient to define the extent and distribution of conserved segments between these two species, because the order of loci is often rearranged. A 5000-rad cattle whole-genome radiation hybrid (WG-RH) panel was constructed to provide high-resolution comparative maps and also to integrate linkage maps of microsatellites with evolutionary conserved genes and transcripts in a single ordered map. We used the WG-RH panel to construct radiation hybrid maps of bovine Chromosomes (Chrs) 15 and 29 (BTA15 and BTA29), integrating microsatellites from published linkage maps with selected genes. The comprehensive map of BTA15 consists of 24 markers. 13 of which were placed in the framework map. Eleven molecular markers compose the comprehensive map of BTA29. seven of which were placed in the framework map. We identified the homologous regions between bovine Chr 15 (BTA15) and human Chrs 5 and 11 (HSA5 and HSA11), as well as between BTA29 and HSA11, the present study demonstrates that WG-RH mapping is an efficient method for integrating multiple genetic maps into one map and for incorporating monomorphic Type I loci into ordered maps for comparison between species.

Cytotaxonomy of the crickets Endecous Saussure, 1878 with an overview of the chromosomes of Phalangopsinae Group (Orthoptera: Phalangopsinae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chromosome analysis in Pseudopaludicola (Anura, Leiuperidae), with description of sex chromosomes XX/XY in P-saltica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Characteristics of NOR-banded chromosomes of Mangalarga horses

The nucleolar organizer regions (NORs) of Mangalarga horses were characterized by analysis of NOR-banded metaphase chromosomes according to the technique of Goodpasture and Bloom (Chromosoma 53: 37-50, 1975). NOR banding was detected by silver staining in the telomeric region of the short arm of pair no. 1, in the region adjacent to the centromere of the long arm of pair no. 25 and in the proximal region of the long arm of pair no. 31. Associations of NOR-bearing chromosomal regions occurred in 12% of all metaphases and were frequent between the chromosomes of pair no. 1. Most (52.15%) of the NOR bands appeared on four chromosomes in both males and females. The maximum number of NOR-banded chromosomes was six, though only 11.34% of the cells examined showed this characteristic.