Intense genomic reorganization in the genusOecomys(Rodentia, Sigmodontinae): comparison between DNA barcoding and mapping of repetitive elements in three species of the Brazilian Amazon.
OecomysThomas, 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 severalOecomysspecies, suggesting the presence of a complex of species. The present work had the goal of contributing to the genetic characterization of the genusOecomysin the Brazilian Amazon. Thirty specimens were collected from four locations in the Brazilian Amazon and three nominal species recognized:Oecomys auyantepui(Tate, 1939),Oecomys bicolor(Tomes, 1860) andOecomys rutilus(Anthony, 1921). COI sequence analysis groupedOecomys auyantepui,Oecomys bicolorandOecomys rutilusspecimens into one, three and two clades, respectively, which is consistent with their geographic distribution. Cytogenetic data forOecomys auyantepuirevealed the sympatric occurrence of two different diploid numbers, 2n=64/NFa=110 and 2n=66/NFa=114, suggesting polymorphism whileOecomys bicolorexhibited 2n=80/NFa=142 andOecomys 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 inOecomys auyantepui. The data presented in this work reinforce intra- and interspecific variations observed in the diploid number ofOecomysspecies and indicate that chromosomal rearrangements have led to the appearance of different diploid numbers and karyotypic formulas.
Universidade Federal do Amazonas, Instituto de Ciências Biológicas, Departamento de Genética, Laboratório de Citogenômica Animal, Av. General Rodrigo Otávio, 3000, Japiim, Zip code 69077-000 Manaus, AM, Brazil.
Renan Gabriel
RG
Gomes Júnior
Universidade Federal do Amazonas, Instituto de Ciências Biológicas, Departamento de Genética, Laboratório de Citogenômica Animal, Av. General Rodrigo Otávio, 3000, Japiim, Zip code 69077-000 Manaus, AM, Brazil.
Carlos Henrique
CH
Schneider
Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936 Zip Code 69077-000, Manaus, AM, Brazil.
Thatianna
T
de Lira
Universidade Federal do Amazonas, Instituto de Ciências Biológicas, Departamento de Genética, Laboratório de Citogenômica Animal, Av. General Rodrigo Otávio, 3000, Japiim, Zip code 69077-000 Manaus, AM, Brazil.
Natália Dayane Moura
ND
Carvalho
Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936 Zip Code 69077-000, Manaus, AM, Brazil.
Eliana
E
Feldberg
Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936 Zip Code 69077-000, Manaus, AM, Brazil.
Maria Nazareth Ferreira
MN
da Silva
Universidade Federal da Integração Latino Americana, Laboratório de Genética, Av. Tarquínio Joslin dos Santos, 1000, Jardim Universitário, Zip code 85857-190, Foz do Iguaçu, PR, Brazil.
Maria Claudia
MC
Gross
COI; FISH; Oryzomyini; heterochromatin; rDNA; telomere