Intense genomic reorganization in the genus Oecomys (Rodentia, Sigmodontinae): comparison between DNA barcoding and mapping of repetitive elements in three species of the Brazilian Amazon

By

Gomes Junior, Renan Gabriel
Schneider, Carlos Henrique
Lira, Thatianna de
Carvalho, Natalia
Feldberg, Eliana
Silva, Maria Nazareth F. da
Gross, Maria Claudia

Type

Article

Date of Publication

2016

Original Publication

Comparative cytogenetics : international journal of plant & animal cytogenetics, karyosystematics and molecular systematics

Volume

10

Series / Issue

Issue: 3

Pages

401-426

Subjects

COI , Fish , heterochromatin , Oryzomyini , rDNA , telomere

Contributed by

Pensoft Publishers

Language

English

Published by

St. Petersburg, Russia [Published] with technical support of Zoological Institute RAS [2007]-

Identifiers

DOI: https://doi.org/10.3897/compcytogen.v10i3.8306

 

Abstract

Oecomys Thomas, 1906 is one of the most diverse and widely distributed genera within the tribe Oryzomyini. At least sixteen species in this genus have been described to date, but it is believed this genus contains undescribed species. Morphological, molecular and cytogenetic study has revealed an uncertain taxonomic status for several Oecomys species, suggesting the presence of a complex of species. The present work had the goal of contributing to the genetic characterization of the genus Oecomys in the Brazilian Amazon. Thirty specimens were collected from four locations in the Brazilian Amazon and three nominal species recognized: Oecomys auyantepui (Tate, 1939), O. bicolor (Tomes, 1860) and O. rutilus (Anthony, 1921). COI sequence analysis grouped O. auyantepui, O. bicolor and O. rutilus specimens into one, three and two clades, respectively, which is consistent with their geographic distribution. Cytogenetic data for O. auyantepui revealed the sympatric occurrence of two different diploid numbers, 2n=64/NFa=110 and 2n=66/NFa=114, suggesting polymorphism while O. bicolor exhibited 2n=80/NFa=142 and O. rutilus2n=54/NFa=90. The distribution of constitutive heterochromatin followed a species-specific pattern. Interspecific variation was evident in the chromosomal location and number of 18S rDNA loci. However, not all loci showed signs of activity. All three species displayed a similar pattern for 5S rDNA, with only one pair carrying this locus. Interstitial telomeric sites were found only in O. auyantepui. The data presented in this work reinforce intra- and interspecific variations observed in the diploid number of Oecomys species and indicate that chromosomal rearrangements have led to the appearance of different diploid numbers and karyotypic formulas.