Heterochromatin variation and LINE-1 distribution in Artibeus (Chiroptera, Phyllostomidae) from Central Amazon, Brazil

A genomic portrait of Sturnira parvidens: mitochondrial chromosome, repetitive elements, and microsatellite discovery

The yellow-shouldered bat, Sturnira parvidens (Phyllostomidae), is an abundant and widespread species in southern North America and Mesoamerica. Despite its important ecological role, no genomic resources exist for this species. Using low-coverage short Illumina 150 bp pair-end reads sequencing, this study reports the mitochondrial chromosome and nuclear repetitive elements, including microsatellites, in S. parvidens. The mitochondrial genome of S. parvidens is 16,612 bp in length and is comprised of 13 protein-coding genes, 2 ribosomal RNA genes, and 22 transfer RNA genes. Repetitive elements constituted ~67% of the nuclear genome while ~33% of the genome represented single- or low-copy sequences. A moderate proportion of repetitive sequences (31% putative families) could not be assigned to known repeat element families. Considering only annotated repetitive elements, the most ubiquitous repetitive elements belonged to Class I-LINE and Satellite DNA, which were considerably more abundant than Class I-LTR elements and Class II-DNA transposons (TcMar-Mariner and hAT-Charlie). A total of 193 microsatellites were identified.

Comparative cytogenetics of two species of Dermanura (Chiroptera, Phyllostomidae) in Midwestern Brazil

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.

Chromosomal Evolution in Chiroptera

Chiroptera is the second largest order among mammals, with over 1300 species in 21 extant families. The group is extremely diverse in several aspects of its natural history, including dietary strategies, ecology, behavior and morphology. Bat genomes show ample chromosome diversity (from 2n = 14 to 62). As with other mammalian orders, Chiroptera is characterized by clades with low, moderate and extreme chromosomal change. In this article, we will discuss trends of karyotypic evolution within distinct bat lineages (especially Phyllostomidae, Hipposideridae and Rhinolophidae), focusing on two perspectives: evolution of genome architecture, modes of chromosomal evolution, and the use of chromosome data to resolve taxonomic problems.