Chromosomal evolution in the Brazilian geckos of the genus Gymnodactylus (Squamata, Phyllodactylidae) from the biomes of Cerrado, Caatinga and Atlantic rain forest: evidence of Robertsonian fusion events and supernumerary chromosomes.

Chromosomes of the South American geckos Gymnodactylus amarali and G. geckoides from open and dry areas of the Cerrado and Caatinga biomes in Brazil, respectively, were studied for the first time, after conventional and AgNOR staining, CBG- and RBG-banding, and FISH with telomeric sequences. Comparative analyses between the karyotypes of open areas and the previously studied Atlantic forest species G. darwinii were also performed. The chromosomal polymorphisms detected in populations of G. amarali from the states of Goiás and Tocantins is the result of centric fusions (2n = 38, 39 and 40), suggesting a differentiation from a 2n = 40 ancestral karyotype and the presence of supernumerary chromosomes. The CBG- and RBG-banding patterns of the Bs are described. G. geckoides has 40 chromosomes with gradually decreasing sizes, but it is distinct from the 2n = 40 karyotypes of G. amarali and G. darwinii due to occurrence of pericentric inversions or centromere repositioning. NOR location seems to be a marker for Gymnodactylus, as G. amarali and G. geckoides share a medium-sized subtelocentric NOR-bearing pair, while G. darwinii has NORs at the secondary constriction of the long arm of pair 1. The comparative analyses indicate a non-random nature of the Robertsonian rearrangements in the genus Gymnodactylus.

Chromosomal studies on sphaerodactyl lizards of genera Gonatodes and Coleodactylus (Squamata, Gekkonidae) using differential staining and fragile sites analyses.

The karyotypes of three species of sphaerodactyl gekkonid lizards are described after conventional and differential staining. Karyotypes of Gonatodeshumeralis and G. hasemani are formed by a gradual series of 32 acrocentric chromosomes, similar to those already published for other species of the genus. G. humeralis shows multiple Ag-NORs with intra-individual variability, and positive C-bands located at centromeric and telomeric regions of several chromosome pairs. Coleodactylus amazonicus, the first non-Gonatodes sphaerodactyl studied so far karyologically, exhibits 36 acrocentric/subtelocentric chromosomes and a single pair of Ag- NORs. Fragile sites were detected on two medium-sized chromosome pairs in the karyotype of G. humeralis, most of them obtained in BrdU-treated culture preparations. These sites may represent a putative fission/fusion spot involved in the differentiation of G. humeralis-like 2n = 32 and C. amazonicus-like 2n = 36 karyotypes. Our results, especially on the location of Ag-NORs and the description of fragile sites, are relevant in improving our knowledge about the events of chromosome evolution in this extremely variable and poorly known group of lizards.

Freqüência de anemia infecciosa em eqüinos no Acre, 1986 a 1996 / Frequency of equine infectious anemia in the State of Acre, Brazil, from 1986 to 1996

Foram analisadas as fichas de 9.963 eqüídeos do Acre, submetidos ao teste de imunodifusäo em gel de ágar (IDGA) para anemia infecciosa eqüina (AIE), no período de 1986 a 1996. As regiöes sócio-ecológicas da Bacia do Alto Juruá, Alto Acre e Alta Bacia do Purus apresentaram os maiores índices da doença, o que caracteriza a associaçäo entre regiäo e positividade. Essas áreas säo fronteiriças com o Peru, Bolívia e o Estado do Amazonas, säo distantes de Rio Branco, capital do Estado, onde muitas vezes é difícil o acesso pelas estradas, revelando serem áreas de risco. As regiöes Oriental e Rio Branco apresentaram baixos índices de positividade. Näo se observou diferença estatística entre animais positivos e negativos quanto à espécie, sexo, raça e idade

Freqüência de anemia infecciosa em eqüinos no Acre, 1986 a 1996

Data from 9,963 formularies of equines from Acre State (1986-1996) examined for equine infectious anemia (EIA) by the AGID test were analyzed. The socio-ecological regions in Alto Juruá, Alto Acre and Alto Purus rivers basins showed the highest levels of disease, characterizing an association between these regions and positivity. These risk regions are border areas with the State of Amazonas, Peru and Bolivia, far from the capital city of the State of Acre (Rio Branco) and access by roads is often difficult. The regions Oriental and Rio Branco showed low levels of positivity. No differences were found regarding to animal species, sex, race and age.

Foram analisadas as fichas de 9.963 eqüídeos do Acre, submetidos ao teste de imunodifusão em gel de ágar (IDGA) para anemia infecciosa eqüina (AIE), no período de 1986 a 1996. As regiões sócio-ecológicas da Bacia do Alto Juruá, Alto Acre e Alta Bacia do Purus apresentaram os maiores índices da doença, o que caracteriza a associação entre região e positividade. Essas áreas são fronteiriças com o Peru, Bolívia e o Estado do Amazonas, são distantes de Rio Branco, capital do Estado, onde muitas vezes é difícil o acesso pelas estradas, revelando serem áreas de risco. As regiões Oriental e Rio Branco apresentaram baixos índices de positividade. Não se observou diferença estatística entre animais positivos e negativos quanto à espécie, sexo, raça e idade.