Karyotypes of Akodon orophilus Osgood 1913 and Thomasomys sp. (Rodentia: Sigmodontinae) from Huánuco, Peru

Authors

  • Víctor Pacheco Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Av. Arenales 1256, Jesús María, Lima, Perú.
  • Jesús H. Córdova 2 Departamento de Herpetología, Laboratorio de Citogenética Molecular “Javier Zapata Arias”, Museo de Historia Natural, Universidad Nacional Mayor de San Marcos.
  • Margarita Velásquez 3 Laboratorio de Genética Humana- Facultad de Ciencias Biologicas, Universidad Nacional Mayor de San Marcos.

DOI:

https://doi.org/10.15381/rpb.v19i1.796

Keywords:

Akodon, Thomasomys, karyotype, Yungas, Sigmodontinae

Abstract

Conventional chromosomal preparations were made of three native mice from Huánuco, Peru: a male and a female of Thomasomys sp., and a male of Akodon orophilus. Thomasomys sp. had a karyotype of 2n = 42, XY (n = 21), meanwhile A. orophilus presented 2n = 22, XY (n = 11). Comparisons between chromosomal pairs from the existent literature indicate that both are new karyotypes. Thomasomys sp. has a distinct sexual Y chromosome, the only metacentric (m) reported for the genus. The chromosomes X and Y of A. orophilus are acrocentrics (a); and the length of chromosome Y (2/3 of the length of X) distinguishes A. orophilus from other congeneric. Because the structural differences between the sexual chromosomes usually generates mechanism of reproductive isolation at intraspecific level and are bigger still in interspecific crosses, we concluded that the karyotypes reported here support the validity of the species A. orophilus and suggest that Thomasomys sp. represents a new species to science.

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Published

04/16/2012

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How to Cite

Pacheco, Víctor, Jesús H. Córdova, and Margarita Velásquez. 2012. “Karyotypes of Akodon Orophilus Osgood 1913 and Thomasomys Sp. (Rodentia: Sigmodontinae) from Huánuco, Peru”. Revista Peruana De Biología 19 (1): 107-10. https://doi.org/10.15381/rpb.v19i1.796.