Assessment of dispersal and population structure of Norway rats (Rattus norvegicus) in a seaport setting Fernanda Gatto-Almeida, Amanda de Araújo Soares, Tiago Marafiga Degrandi, Liliani Marilia Tiepolo, Florian Pichlmueller, et al. Urban Ecosystems, 2022 Seaports are introduction hotspots for invasive alien species (IAS). This is especially true for rodents, which have accompanied humans around the globe since the earliest days of ocean-going voyages. The rapid spread of IAS soon after arrival in a new environment is facilitated by further human-mediated transport or landscape features, like roads. By measuring genetic diversity and structure to investigate dispersal pathways, we gained insight into the transport, spread and establishment stages of a biological invasion, leveraging the most common rodent species (R. norvegicus) in this setting. We characterized the genetic structure of three Norway rat populations along a busy industrial road used by trucks to access the Port area in Paranaguá city (Brazil). A total of 71 rats were genotyped using 11 microsatellite markers. The results revealed a pattern of gene flow contrary to the expected stepping-stone model along the linear transect, with the two furthest apart populations being clustered together. We hypothesize that the observed outcome is explained by natural dispersal along the corridor being lower than human-mediated transport. The sampled area furthest from the port is a gas station frequented by trucks which are considered the most likely mode of transportation. In terms of management strategies, we suggest more emphasis should be put on cargo surveillance to lower the risk of Norway rat dispersal, not only for biosecurity, but also for sanitary reasons, as this port is a major grain trading point.
Introducing the Bird Chromosome Database: An Overview of Cytogenetic Studies in Birds Tiago M. Degrandi, Suziane A. Barcellos, Alice L. Costa, Analía D.V. Garnero, Iris Hass, et al. Cytogenetic and Genome Research, 2020 Bird chromosomes, which have been investigated scientifically for more than a century, present a number of unique features. In general, bird karyotypes have a high diploid number (2n) of typically around 80 chromosomes that are divided into macro- and microchromosomes. In recent decades, FISH studies using whole chromosome painting probes have shown that the macrochromosomes evolved through both inter- and intrachromosomal rearrangements. However, chromosome painting data are available for only a few bird species, which hinders a more systematic approach to the understanding of the evolutionary history of the enigmatic bird karyotype. Thus, we decided to create an innovative database through compilation of the cytogenetic data available for birds, including chromosome numbers and the results of chromosome painting with chicken (Gallus gallus) probes. The data were obtained through an extensive literature review, which focused on cytogenetic studies published up to 2019. In the first version of the “Bird Chromosome Database (BCD)” (https://sites.unipampa.edu.br/birdchromosomedatabase) we have compiled data on the chromosome numbers of 1,067 bird species and chromosome painting data on 96 species. We found considerable variation in the diploid numbers, which ranged from 40 to 142, although most (around 50%) of the species studied up to now have between 78 and 82 chromosomes. Despite its importance for cytogenetic research, chromosome painting has been applied to less than 1% of all bird species. The BCD will enable researchers to identify the main knowledge gaps in bird cytogenetics, including the most under-sampled groups, and make inferences on chromosomal homologies in phylogenetic studies.
B Chromosome Diversity and Repetitive Sequence Distribution in an Isolated Population of Akodon montensis (Rodentia, Sigmodontinae) Amanda A. Soares, Jonathan P. Castro, Pedro Balieiro, Sidnei Dornelles, Tiago M. Degrandi, et al. Cytogenetic and Genome Research, 2018 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 <i>Akodon montensis </i>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.
Karyotype description and comparative analysis in Ringed Kingfisher and Green Kingfisher (Coraciiformes, Alcedinidae) Tiago Marafiga Degrandi, Jean Carlo Pedroso de Oliveira, Amanda de Araújo Soares, Mario Angel Ledesma, Iris Hass, et al. Comparative Cytogenetics, 2018 Kingfishers comprise about 115 species of the family Alcedinidae, and are an interesting group for cytogenetic studies, for they are among birds with most heterogeneous karyotypes. However, cytogenetics knowledge in Kingfishers is extremely limited. Thus, the aim of this study was to describe the karyotype structure of the Ringed Kingfisher (Megaceryletorquata Linnaeus, 1766) and Green Kingfisher (Chloroceryleamericana Gmelin, 1788) and also compare them with related species in order to identify chromosomal rearrangements. The Ringed Kingfisher presented 2n = 84 and the Green Kingfisher had 2n = 94. The increase of the chromosome number in the Green Kingfisher possibly originated by centric fissions in macrochromosomes. In addition, karyotype comparisons in Alcedinidae show a heterogeneity in the size and morphology of macrochromosomes, and chromosome numbers ranging from 2n = 76 to 132. Thus, it is possible chromosomal fissions in macrochromosomes resulted in the increase of the diploid number, whereas chromosome fusions have originated the karyotypes with low diploid number.
Range extension of the Atlantic forest hocicudo, Oxymycterus dasytrichus (Schinz, 1821), to the state of Santa Catarina, Southern Brazil Willian Thomaz Peçanha, Gislene Lopes Gonçalves, Sérgio Luiz Althoff, Thales Renato Ochotorena de Freitas, Iris Hass Check List, 2016 Six individuals of Oxymycterus dasytrichus (Schinz, 1821) were found on the coast of Paraná and Santa Catarina (in the Atlantic Forest), expanding the known geographical distribution of the species ca. 280 km southward. The specimens represent the first record of the species for the state of Santa Catarina, and new localities to the region of southern Paraná. The identification of the species relied mainly on interspecies comparative assessment of genetic distance based on DNA sequences data from the mitochondrial cytochrome-b gene and geographic distribution of taxa across biomes, particularly in the Atlantic Forest. Our findings highlight the role of protected areas, particularly the Guaraqueçaba Environmental Protection Area, to preserve small mammals.
Bibimys labiosus Winge, 1887 (Mammalia: Rodentia: Sigmodontinae): New records in Paraná state, southern Brazil, and update of the known geographic distribution Guilherme Grazzini, Josias Alan Rezini, Beatrice Stein Boraschi dos Santos, Fernando José Venâncio, Fernanda Gatto-Almeida, et al. Check List, 2015 Bibimys is a genus still poorly known in its basic aspects, such as systematics, natural history and geographic distribution. In Brazil, only Bibimys labiosus is recorded, with occasional records spread in time and space. This paper presents four new localities of the species in Araucaria Forest, Paraná state, extending its distribution 150 km southwards. Additionally, a map of the known distribution of the species in Brazil and in Araucaria Forest is provided. The records point toward the lack of knowledge about basic aspects of the small non-flying mammal fauna in the plateau regions of Brazil.
