Citotaxonomy and chromosome evolution in Oligoryzomys (Rodentia, Sigmodontinae).

Author(s)

Camilla Bruno Di Nizo

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2013-06-14

Examining board members

Maria José de Jesus Silva; Renata Cecilia Amaro; Mario de Vivo

• Advisor: Maria José de Jesus Silva

Abstract

Oligoryzomys is the most specious genus within the tribe Oryzomyini and it is distributed throughout Neotropical region. This work aims to contribute to citotaxonomy and to investigate the chromosomal evolution of the genus. A total of 117 individuals were cytogenetically analysed, and they belong to the species: O. flavescens (2n=64-66, FN=66), O. fornesi (2n=62, FN=64), O. microtis (2n=64, FN=64), O. moojeni (2n=70, FN=72), O. nigripes (2n=62, FN=78-82), O. stramineus (2n=52, FN=68), and Oligoryzomys sp. A (2n=70, FN=72). The first six species possess species-specific karyotypes, and therefore we emphasize the importance of cytogenetic studies for citotaxonomy. Comparative chromosome painting (Zoo-FISH) with O. moojeni probes hybridized to 29 segments on metaphases of O. fornesi, 30 on O. microtis, 31 on O. nigripes, and 32 on O. rupestris and Oligoryzomys sp. 2. The results showed an extensive genomic reshuffling, due to fissions, tandem and Robertsonian fusions, loss/inactivation or repositioning of centromeres. (AU)

• FAPESP's process: 10/03432-0 - Chromosome evolution on the genus Oligoryzomys (Cricetidae: Sigmodontinae): comparative studies by conventional cytogenetic and chromosome painting
• Grantee: Camilla Bruno Di Nizo
• Support Opportunities: Scholarships in Brazil - Master