B Chromosome Diversity and Repetitive Sequence Distribution in an Isolated Population of Akodon montensis (Rodentia, Sigmodontinae).

B chromosomes are supernumerary chromosomes found in the karyotypes of approximately 15% of all eukaryotic species. They present parasitic behavior and do not follow the standard Mendelian pattern of inheritance, resulting in an imbalance in gametogenesis. The evolutionary dynamics of B chromosomes is still unknown for many species, but studies indicate that the accumulation of repetitive sequences plays an important role in the differentiation of these elements. We analyzed morphology, frequency, and possible homologies amongst different B chromosomes found in an isolated Akodon montensis population in southern Brazil. Repetitive sequences (18S, 5S rDNA and telomeric sequences) were used to test for their accumulation on the supernumerary chromosomes and describe their localization in the species. The results indicate 4 different B chromosome morphotypes, and DNA libraries were generated for 3 of them. 18S rDNA was labelled polymorphically, except in the B chromosomes, whereas the 5S rDNA was located exclusively in an interstitial position on the long arm of chromosome 5. Chromosome painting with the B probes based on FISH revealed a homologous composition for all B chromosome morphotypes and no homology with the chromosomes in the A complement. B chromosomes found in this population may have a common origin and subsequently diversified in size and morphology.

A new species of swamp rat of the genus Scapteromys waterhouse, 1837 (Rodentia: Sigmodontinae) endemic to Araucaria angustifolia forest in Southern Brazil.

A new species of swamp rat of the genus Scapteromys from the Meridional Plateau of Southern Brazil is described. Morphological, molecular, and karyological analysis support the recognition of the new species, distinct from S. aquaticus and S. tumidus. Scapteromys sp. nov. is significantly smaller than the congeneric taxa considering most of the external and craniometric measurements and the pelage is conspicuously grayer and darker. It can be distinguished from S. tumidus by the laterally extended thenar pad of the manus and the parallel edges of the hamular process of the pterygoid, and from S. aquaticus by a grayer and darker pelage and smaller values of most external and craniometric measurements. Karyological analysis indicated a difference in chromosome numbers across the distributional range: 2n=34 and 2n=36. A total of 11 haplotypes were found along the range of the new species within the biogeographic province of Araucaria angustifolia Forest. Strongly supported substructure was found within the new taxon, resulting in two reciprocally monophyletic clades.

Identificação das espécies brasileiras de Akodon (Rodentia: Cricetidae: Sigmodontinae) através da microestrutura dos pelos / Identification of the brazilian species of Akodon (Rodentia: Cricetidae: Sigmodontinae) through the microstructure of the hair

No Brasil há 10 espécies de Akodon Meyen, 1833 e a maioria apresenta algum grau de sobreposição geográfica havendo inclusive registros de simpatia. A identificação das espécies é difícil e pode ser feita pela análise da estrutura morfológica de pelos. Assim, para a identificação da microestrutura de pelos de nove espécies brasileiras de Akodon, foram utilizados pelos-guardas primários de amostras de coleções zoológicas. Foi adotado o método de análise das escamas cuticulares e da medula. O padrão de cutícula para todas as espécies foi folidáceo estreito. Já para a medula foram reconhecidos três padrões básicos como multisseriada alveolar, multisseriada listrada e misto de alveolar e listrada. Akodon cursor é a única espécie com predomínio de quatro fileiras sendo que exemplares 2n = 14 e 2n = 15 apresentam medula alveolar e o 2n = 16, medula listrada e células longilíneas. Para Akodon paranaensis e A. lindberghi a medula se alterna entre três e quatro fileiras. As demais espécies apresentam três fileiras. Akodon mystax apresenta um maior espaçamento entre as células. Akodon reigi possui o setor intermediário com fileiras ovaladas e bem ligadas e Akodon toba tem as células da fileira central variando com uma e duas células alveolares pequenas. No padrão listrado, Akodon montensis apresenta espaço intercelular mais estreito em relação à espessura da célula. No padrão misto, Akodon azarae apresenta células com contorno evidente, já Akodon serrensis as células apresentam formato irregular. Assim, o uso da microestrutura dos pelos como ferramenta para a identificação das espécies de Akodon mostrou-se perfeitamente viável.

There are 10 species of Akodon Meyen, 1833 in Brazil and most have some degree of geographic overlap, even with records of sympatry between some species. The identification of the species is difficult and can be performed by the analysis of the morphological structure of hair. Thus, in order to identify the microstructure of the nine Brazilian species of Akodon, guard-hairs samples from zoological collections were used. We adopted the method of analysis of the cuticle scales and medulla. The cuticle pattern for all species was narrow leaf shaped. For the medulla three basic patterns have been recognized: alveolar multiseriate, multiseriate striped and a mixture of alveolar and striped. Akodon cursor is the only species which has a predominance of four layers of cells, the specimens 2n = 14 and 2n = 15 have an alveolar medulla and the specimen 2n = 16, has a striped medulla and elongated cells. For Akodon paranaensis and A. lindberghi the medulla alternates between three and four layers. The others species have three layers. Akodon mystax, have a larger spaces between the cells. Akodon reigi shows an intermediary sector with layers of oval and well connected cells and for Akodon toba, the cells of the central layer are found in one or two small alveolar layers. In the striped pattern, Akodon montensis have narrow intercellular space in regard to the thickness of the cell. In a mixed pattern, Akodon azarae presents cells with clear outline, and Akodon serrensis show cells with irregular shape. Thus, the use of the microstructure of hairs as a tool for identification of the species of Akodon proved to be practicable.

Description of the karyotype of Rhagomys rufescens Thomas, 1886 (Rodentia, Sigmodontinae) from Southern Brazil Atlantic forest.

Rhagomys rufescens (Rodentia: Sigmodontinae) is an endemic species of the Atlantic forest from Southern and Southeastern Brazil. Some authors consider Rhagomys as part of the tribe Thomasomyini; but its phylogenetic relationships remain unclear. Chromosomal studies on eight specimens of Rhagomys rufescens revealed a diploid number of 2n = 36 and a number of autosome arms FN = 50. GTG, CBG and Ag-NOR banding and CMA(3) /DAPI staining were performed on metaphase chromosomes. Eight biarmed and nine acrocentric pairs were found in the karyotype of this species. The X and Y chromosomes were both acrocentric. Most of the autosomes and the sex chromosomes showed positive C-bands in the pericentromeric region. The X chromosome showed an additional heterochromatic block in the proximal region of the long arm. Nucleolus organizer regions (NORs) were located in the pericentromeric region of three biarmed autosomes (pairs 4, 6 and 8) and in the telomeric region of the short arm of three acrocentrics (pairs 10, 12 and 17). CMA (3) /DAPI staining produced fluorescent signals in many autosomes, especially in pairs 4, 6, and 8. This study presents cytogenetic data of Rhagomys rufescens for the first time.

Evaluation of genetic variability in the collared peccary Pecari tajacu and the white-lipped peccary Tayassu pecari by microsatellite markers.

In this study, the microsatellite technique was used to evaluate the genetic variability in populations of collared and white-lipped peccaries kept in captivity. Six primers developed for domestic pigs were used and amplified in both species. They revealed the presence of five polymorphic loci and one monomorphic locus. The polymorphic loci included 4 of the 16 alleles in collared peccaries, and 3 of the 10 alleles in the white-lipped peccaries. Polymorphic information content (PIC) in both species and all the loci was highly informative. The probability of paternity exclusion (PEC), if one of the parents is known, was almost as high in white-lipped peccaries (95.53%) as in the collared (99,48%). The Fst values for collared (0.042) and white-lipped (0.1387) peccaries showed that both populations are not structured. The Fis values for all loci, except ACTG2 in white-lipped peccaries (-0.0275) and in both species (0.1985 to 0.9284 in collared peccaries and 0.3621 to 0.4754 in the white-lipped), revealed a high level of homozygosis, probably caused by inbreeding. Data on heterologous amplification and genetic variability in collared and white-lipped peccaries are presented for the first time.

Description of the karyotype of Rhagomys rufescens Thomas, 1886 (Rodentia, Sigmodontinae) from Southern Brazil Atlantic forest

Rhagomys rufescens (Rodentia: Sigmodontinae) is an endemic species of the Atlantic forest from Southern and Southeastern Brazil. Some authors consider Rhagomys as part of the tribe Thomasomyini; but its phylogenetic relationships remain unclear. Chromosomal studies on eight specimens of Rhagomys rufescens revealed a diploid number of 2n = 36 and a number of autosome arms FN = 50. GTG, CBG and Ag-NOR banding and CMA3/DAPI staining were performed on metaphase chromosomes. Eight biarmed and nine acrocentric pairs were found in the karyotype of this species. The X and Y chromosomes were both acrocentric. Most of the autosomes and the sex chromosomes showed positive C-bands in the pericentromeric region. The X chromosome showed an additional heterochromatic block in the proximal region of the long arm. Nucleolus organizer regions (NORs) were located in the pericentromeric region of three biarmed autosomes (pairs 4, 6 and 8) and in the telomeric region of the short arm of three acrocentrics (pairs 10, 12 and 17). CMA3/DAPI staining produced fluorescent signals in many autosomes, especially in pairs 4, 6, and 8. This study presents cytogenetic data of Rhagomys rufescens for the first time.

Evaluation of genetic variability in the collared peccary Pecari tajacu and the white-lipped peccary Tayassu pecari by microsatellite markers

In this study, the microsatellite technique was used to evaluate the genetic variability in populations of collared and white-lipped peccaries kept in captivity. Six primers developed for domestic pigs were used and amplified in both species. They revealed the presence of five polymorphic loci and one monomorphic locus. The polymorphic loci included 4 of the 16 alleles in collared peccaries, and 3 of the 10 alleles in the white-lipped peccaries. Polymorphic information content (PIC) in both species and all the loci was highly informative. The probability of paternity exclusion (PEC), if one of the parents is known, was almost as high in white-lipped peccaries (95.53 percent) as in the collared (99,48 percent). The Fst values for collared (0.042) and white-lipped (0.1387) peccaries showed that both populations are not structured. The Fis values for all loci, except ACTG2 in white-lipped peccaries (-0.0275) and in both species (0.1985 to 0.9284 in collared peccaries and 0.3621 to 0.4754 in the white-lipped), revealed a high level of homozygosis, probably caused by inbreeding. Data on heterologous amplification and genetic variability in collared and white-lipped peccaries are presented for the first time.

Chromosomal phylogeny of four Akodontini species (Rodentia, Cricetidae) from southern Brazil established by Zoo-FISH using Mus musculus (Muridae) painting probes.

We established chromosome homology maps between Mus musculus (MMU) and five species of the Akodontini tribe, Akodon cursor (2n = 14, 15 and 16), A. montensis (2n = 24), A. paranaensis (2n = 44), A. serrensis (2n = 46) and Oligoryzomys flavescens (2n = 66) by Zoo-FISH (fluorescence in situ hybridization) using mouse chromosome-specific probes. The aims of this study were (1) to detect the chromosomal rearrangements responsible for the karyotype variation in this tribe and (2) to reconstruct the phylogenetic relationships among these species. We observed four common syntenic associations of homologous chromosome segments, of which the MMU 7/19 has been described previously in other rodents from Africa, Asia and Europe, and might represent a phylogenetic link between the Old World and Neotropical rodents. The remaining three associations (3/18, 6/12 and 8/13) have been observed exclusively in Neotropical rodents so far, which at present can be considered synapomorphic traits of this group. Five further mouse chromosomes (MMU 4, 9, 14, 18 and 19) were each found evolutionarily conserved as a separate syntenic unit. Our phylogenetic analysis using parsimony and heuristic search detected one consistent group, separating the Akodontini from other rodents.

Chromosome reshuffling in birds of prey: the karyotype of the world's largest eagle (Harpy eagle, Harpia harpyja) compared to that of the chicken (Gallus gallus).

Like various other diurnal birds of prey, the world's largest eagle, the Harpy (Harpia harpyja), presents an atypical bird karyotype with 2n=58 chromosomes. There is little knowledge about the dramatic changes in the genomic reorganization of these species compared to other birds. Since recently, the chicken provides a "default map" for various birds including the first genomic DNA sequence of a bird species. Obviously, the gross division of the chicken genome into relatively gene-poor macrochromosomes and predominantly gene-rich microchromosomes has been conserved for more than 150 million years in most bird species. Here, we present classical features of the Harpy eagle karyotype but also chromosomal homologies between H. harpyja and the chicken by chromosome painting and comparison to the chicken genome map. We used two different sets of painting probes: (1) chicken chromosomes were divided into three size categories: (a) macrochromosomes 1-5 and Z, (b) medium-sized chromosomes 6-10, and (c) 19 microchromosomes; (2) combinatorially labeled chicken chromosome paints 1-6 and Z. Both probe sets were visualized on H. harpyja chromosomes by multicolor fluorescence in situ hybridization (FISH). Our data show how the organization into micro- and macrochromosomes has been lost in the Harpy eagle, seemingly without any preference or constraints.

Eco-epidemiological survey of Leishmania (Viannia) braziliensis American cutaneous and mucocutaneous leishmaniasis in Ribeira Valley River, Paraná State, Brazil.

Leishmaniasis is endemic since last century in Adrianópolis Municipality, Ribeira Valley and is a serious public health. A study carried out during 1993-2003 on epidemiological surveys conducted in rural communities showed 339 new cases of cutaneous leishmaniasis (CL) detected from four municipalities (Adrianópolis, Cerro Azul, Doutor Ulysses and Rio Branco do Sul). A larger prevalence of cutaneous lesions was observed in rural workers (36%), women with domestic activities (18%), and younger students (31%). Multiple lesions were noticed in 53% of patients, but only one case of mucocutaneous leishmaniasis was reported. Twenty stocks were isolated from patients with characteristics lesions and were identified as Leishmania (Viannia) braziliensis using multi-locus enzyme electrophoresis (MLEE) and Random Amplified DNA (RAPD). In Phlebotominae survey, five species were obtained. Lutzomyia intermedia sl. represented 97.5% in peridomiciliar area and 100% in domicile. A canine serological survey made (Indirect Immunofluorescence Antibody Test, IFAT and Enzyme Linked Immunosorbent Assay, ELISA) in six rural county of Adrianópolis Municipality during 1998-1999 showed that 15.1% (24/159) of dogs were sera reactive. No lesions were observed in dogs and no parasite was isolated from lymph node aspirates and biopsies. In wild reservoirs study, only seven animals (Cricetidae, Desmodus sp. and edentates) were captured, but no parasites were found in culture from deep organs. The paper presents results of our 10 years study on cutaneous leishmaniasis survey in the Ribeira River Valley, East Region of Paraná State, Brazil. Environment changes in this region are also discussed.

Unexpected chromosomal alterations in Tayassu tajacu (Artiodactyla: Tayassuidae) in captivity

Os animais silvestres têm sido utilizados como bioindicadores quando o ambiente é exposto a estressores químicos. Em geral, os agentes químicos podem induzir às alterações cromossômicas dos tipos falhas e quebras. Tayassu tajacu, é uma espécie aparentada dos porcos verdadeiro e apresenta uma grande estabilidade cariotípica. As únicas alterações descritas são em relação a forma do cromossomo X. Foram observadas falhas e quebras cromossômicas durante as análise citogenética. Estas alterações foram detectadas em cromossomos autossômicos. Levantamentos realizados na literatura associados as dados observados nos exemplares estudados, indicam um vermífugo, a base de ivermectina, como o possível causador dessas alterações cromossômicas.

The phylogeny of howler monkeys (Alouatta, Platyrrhini): reconstruction by multicolor cross-species chromosome painting.

We performed multidirectional chromosome painting in a comparative cytogenetic study of the three howler monkey species Alouatta fusca, A. caraya and A. seniculus macconnelli (Atelinae, Platyrrhini) in order to reconstruct phylogenetic relationships within this genus. Comparative genome maps between these species were established by multicolor fluorescence in-situ hybridization (FISH) employing human, Saguinus oedipus and Lagothrix lagothricha chromosome-specific probes. The three species included in this study and previously analyzed howler monkey species were subjected to a phylogenetic analysis on the basis of a data matrix comprised of 98 discrete molecular cytogenetic characters. The results revealed that howler monkeys represent the genus with the most extensive karyotype diversity within Platyrrhini so far analyzed with high levels of intraspecific chromosomal variability. Two different multiple sex chromosome systems were identified. The phylogenetic analysis indicated that Alouatta is a monophyletic clade which can be derived from a proposed ancestral Atelinae karyotype of 2n = 62 chromosomes by a chromosome fusion, a fission, a Y-autosomal translocation and a pericentric inversion. Following these suggestions, the genus Alouatta can be divided into two distinct species groups: the first includes A. caraya and A. belzebul, the second A. s. macconnelli, A. sara, A. s. arctoidea and A. fusca.

Interrelationship between ectoparasites and wild rodents from Tijucas do Sul, State of Paraná, Brazil

Sixteen species of ectoparasites were collected from 50 wild rodents from August 1990 to August 1991, in an area of Araucaria augustifolia forest, in the municility of Tijucas do Sul, State of Paraná, Brazil. Ectoparasites infested 98 per cent of the rodents, with the highest indices of infestation found in the dry-cool season. Species that occurred in single or multiple infestations were recorded. Ectoparasites/host associations were significant (p<0.01) for Gigantolaelaps wolffsohni/Oryzomys nigripes, Polygenis pradoi/Oxymycteurs sp. and Amblyopinus sp./Oxymycteurs sp. The following represent new host records: Polygenis (Polygenis) tripus from Akodon serrensis and Hoplopleura sciuricola from Sciurus aestuans. New geographic records are given for two species of flea and one sucking lice.