title: FISH with whole chromosome and telomeric probes demonstrates huge karyotypic reorganization with ITS between two species of Oryzomyini (Sigmodontinae, Rodentia): Hylaeamys megacephalus probes on Cerradomys langguthi karyotype.
abstract: Rodentia comprises 42 % of living mammalian species. The taxonomic identification can be difficult, the number of species currently known probably being underestimated, since many species show only slight morphological variations. Few studies surveyed the biodiversity of species, especially in the Amazon region. Cytogenetic studies show great chromosomal variability in rodents, with diploid numbers ranging from 10 to 102, making it difficult to find chromosomal homologies by comparative G banding. Chromosome painting is useful, but only a few species of rodents have been studied by this technique. In this study, we sorted whole chromosome probes by fluorescence-activated cell sorting from two Hylaeamys megacephalus individuals, an adult female (2n = 54) and a fetus (2n = 50). We made reciprocal chromosome painting between these karyotypes and cross-species hybridization on Cerradomys langguthi (2n = 46). Both species belong to the tribe Oryzomyini (Sigmodontinae), which is restricted to South America and were collected in the Amazon region. Twenty-four chromosome-specific probes from the female and 25 from the fetus were sorted. Reciprocal chromosome painting shows that the karyotype of the fetus does not represent a new cytotype, but an unbalanced karyotype with multiple rearrangements. Cross-species hybridization of H. megacephalus probes on metaphases of C. langguthi shows that 11 chromosomes of H. megacephalus revealed conserved synteny, 10 H. megacephalus probes hybridized to two chromosomal regions and three hybridized to three regions. Associations were observed on chromosomes pairs 1-4 and 11. Fluorescence in situ hybridization with a telomeric probe revealed interstitial regions in three pairs (1, 3, and 4) of C. langguthi chromosomes. We discuss the genomic reorganization of the C. langguthi karyotype.
authors.affiliation: Laboratório de Citogenética, ICB, Universidade Federal do Pará, Pará, Brazil. cleusanagamachi@gmail.com
authors.forename: Cleusa Yoshiko
authors.initials: CY
authors.lastname: Nagamachi
authors.forename: Julio Cesar
authors.initials: JC
authors.lastname: Pieczarka
authors.forename: Patricia Caroline Mary
authors.initials: PC
authors.lastname: O'Brien
authors.forename: Jamilly Amaral
authors.initials: JA
authors.lastname: Pinto
authors.forename: Stella Miranda
authors.initials: SM
authors.lastname: Malcher
authors.forename: Adenilson Leão
authors.initials: AL
authors.lastname: Pereira
authors.forename: Jorge das Dores
authors.initials: Jd
authors.lastname: Rissino
authors.forename: Ana Cristina
authors.initials: AC
authors.lastname: Mendes-Oliveira
authors.forename: Rogério Vieira
authors.initials: RV
authors.lastname: Rossi
authors.forename: Malcolm Andrew
authors.initials: MA
authors.lastname: Ferguson-Smith
mesh_terms: D000818:Animals; D001938:Brazil; D002871:Chromosome Banding; D020223:Chromosome Painting; D015342:DNA Probes / Q000235:genetics; D004171:Diploidy; D005260:Female; D005434:Flow Cytometry; D059785:Karyotype; D007621:Karyotyping / Q000379:methods*; D008297:Male; D008677:Metaphase; D016205:Sigmodontinae / Q000145:classification* / Q000235:genetics*; D013045:Species Specificity; D016615:Telomere / Q000235:genetics
chemical_list: D015342:DNA Probes