Research Article |
Corresponding author: Karina de Cassia Faria ( karinafaria@unemat.br ) Academic editor: Svetlana V. Pavlova
© 2021 Ricardo Firmino de Sousa, Paulo Cesar Venere, Karina de Cassia Faria.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
de Sousa RF, Venere PC, Faria KC (2021) Comparative cytogenetics of two species of Dermanura (Chiroptera, Phyllostomidae) in Midwestern Brazil. Comparative Cytogenetics 15(2): 89-99. https://doi.org/10.3897/CompCytogen.v15.i2.60577
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Dermanura Gervais, 1856 is represented by small frugivorous bats of the Stenodermatinae subfamily. The taxonomy of this group presents controversies and has been subject to changes, especially since the morphological characters evaluated have left gaps that are difficult to fill regarding good species characterization. Previous studies performed in Dermanura cinerea Gervais, 1856 found that the karyotype of this species has a diploid number of chromosomes equal to 30 and 56 autosomal arms. The objective of the present study was to describe, for the first time, the karyotypes of the species Dermanura anderseni (Osgood, 1916) and Dermanura gnoma (Handley, 1987) based on classical cytogenetic markers. For both species, the diploid number found was 2n = 30 and NFa = 56. Two pairs of chromosomes showed markings of the nucleolus organizing regions (AgNORs) in the species D. anderseni and only one pair in D. gnoma, differing from what has already been described for D. cinerea. The two species analyzed here also showed differences in the sex chromosome system, with D. gnoma showing a neo-XY type system while in D. anderseni the classic XY sexual system was observed. In both species, visualization of the constitutive heterochromatin occurred in the pericentromeric region of all chromosomes, as well as in the short arms of the subtelocentric chromosomes. The present work represents an important expansion of karyotypic information for the subfamily Stenodermatinae, bringing chromosomal features that are possible to use in the taxonomic implications of the group.
Bats, Stenodermatinae, Dermanura gnoma, Dermanura anderseni, karyotype
Among bat families, Phyllostomidae Gray, 1825 is the most morphologically and ecologically diverse, with more than 200 species arranged in 60 genera and 11 subfamilies (
The genus Dermanura has 11 described species (
With the advancement in molecular techniques, and cytogenetic approaches, the integrative analysis becomes important, since more robust proposals are provided to identify the group’s diversification and evolution patterns (
However, knowledge about karyotype data is still scarce for some bat species, and little data has been published for species from South America. Recent studies have been complementing data on chromosomal banding for some species (
Even for many species of Chiroptera, which currently have a reasonable amount of karyotype data, some important gaps can be detected through a detailed data survey. These gaps highlight the importance of expanding chromosomal studies with bats in order to make the information available for the order more robust, especially regarding knowledge about Chiroptera’s chromosomal evolution (
In Dermanura, the only chromosome set ever described is for D. cinerea whose analyses revealed a diploid number of chromosomes equal to 30 and 56 autosomal arms (
Specimens were collected in the municipalities of Nova Xavantina (14°42'28.8"S, 52°21'03.9"W) and Chapada dos Guimarães (15°18'25.57"S, 55°49'06.33"W), both in the state of Mato Grosso – Brazil (Fig.
Capture locations of the species Dermanura anderseni and Dermanura gnoma 1 Nova Xavantina, in Cerradão and Cerrado stricto sensu areas and 2 Chapada dos Guimarães in a Cerrado stricto sensu area, Mato Grosso, Brazil.
Chromosomal preparations were obtained through direct bone marrow extraction, according to the procedure described in
The slides with chromosomal preparations were analyzed using optical microscopy. Slides that showed good quality metaphases were photographed under an Olympus BX51 microscope (Tokyo, Japan). The free edition of Adobe Photoshop Cs6 portable program was used to assemble karyotypes. Afterwards, chromosomes were measured and classified according to the position of the centromere, following
The diploid number found for Dermanura gnoma Handley, 1987 was 2n = 30 and the number of autosomal chromosome arms was NFa = 56. The karyotypes are composed of ten pairs of meta-submetacentric chromosomes (1, 2, 3, 4, 8, 9, 11, 12, 13 and 14) and four subtelocentric chromosome pairs (5, 6, 7 and 10) (Fig.
A, B karyotypes of male individuals stained with Giemsa, highlighted in the boxes the AgNORs marks and the pair of sex chromosomes of A Dermanura gnoma (2n = 30 and NFa= 56) and B Dermanura anderseni (2n = 30 and NFa = 56) C, D karyotypes showing the distribution of constitutive heterochromatin for both species studied C D. gnoma and D D. anderseni. Scale bar: 5 μm.
The karyotype of the species Dermanura anderseni Osgood, 1916 also presented the diploid number 2n = 30 and the number of autosomal chromosome arms NFa = 56. Similar to D. gnoma, the karyotype of this species also presents ten pairs of metacentric chromosomes (1, 2, 3, 4, 8, 9, 11, 12, 13 and 14) and four pairs of subtelocentric chromosomes (5, 6, 7 and 10). The X chromosome is a medium metacentric and the Y chromosome is a small acrocentric. AgNORs were observed in two chromosome pairs: in the short arm of subtelocentric pair no. 7 and in the interstitial position of the long arm of chromosome 13 (Fig.
The cytogenetic analyses presented here indicated that for both species, D. anderseni and D. gnoma, the diploid number found was 2n = 30 and NFa = 56. Among the four species of Dermanura that occur in Brazil, only the D. cinerea karyotype was previously known, with karyotype form also described as 2n = 30 and NFa = 56 (
Our results verified that the sexual system described as neo-XY was found in D. gnoma, while in D. anderseni the classic XY sexual system was observed, where X is a medium metacentric and Y is a small acrocentric. The classic XY sexual system is the most common for bat species studied to date (
Regarding the location of the ribosomal sites,
Observations of the nucleolus organizing regions can be performed through FISH (fluorescence in situ hybridization) using probes for rDNA 5S, 18S and 45S (
Studies on the distribution pattern of constitutive heterochromatins (C+ bands) agreed with what is generally observed among bats; that is, the presence of blocks of C+ bands in the pericentromeric regions of all chromosomes and in the terminal regions of the subtelocentric chromosome pairs (
For the family Phyllostomidae, the C+ bands are located in the pericentromeric regions of the chromosomes (
Studies conducted with chromosomal mapping of different bat families have revealed that this group is characterized by karyotypic conservation, caused by slow chromosomal evolution (Baker et al. 1980;
Overall, the data presented herein expands the cytogenetic knowledge of bats in the Stenodermatinae subfamily and is the first work to analyze the karyotypes of Dermanura gnoma and D. anderseni. The comparative analysis of the species of this subfamily reveals high conservation for this group and reinforces its position as a well-established phylogenetic unit within the order Chiroptera.
We grateful to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – CAPES) for providing the first author with a graduate stipend, the Fundação de Amparo a Pesquisa do Estado de Mato Grosso – FAPEMAT [process 738631/2008] and Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq) [process 4469252014-4].