Syntenic relationship among species of Oryzomyini and Akodontini Tribes (Rodentia: Sigmodontinae)

PABLO SUÁREZ; CLEUSA Y. NAGAMACHI; CECILIA LANZONE; MATIAS M. MALLERET; PATRICIA C. M. OBRIEN; MALCOM A. FERGUSON-SMITH; JÚLIO C. PIECZARKA

Ischia (Napoles)

Workshop; 21st International Colloquium on Animal Cytogenetics and Gene Mapping; 2014

ISPAAM (Istituto Per il Sistema Produzione Animale in Ambiente Mediterráneo)/ Consiglio Nazionale delle Ricerche

Sigmodontinae rodents are one of the most diverse and complex group of mammals in South America, comprising 380 species. About 60% belongs to Oryzomyini and Akodontini tribes. The high specific diversification observed in both tribes is accompanied by a remarkable morphological and numerical diversity of chromosome complements, from 2n=10-86. Developing a consistent hypothesis on the origin of this diversification depends on the correct establishment of chromosomal synteny analyzed in a suitable phylogenetic framework. We analyzed the species Akodon montensis (2n = 24, AMO) and Thaptomys nigrita (2n = 52, TNI) with chromosome probes from Hylaeamys megacephalus (2n = 56, HME) of the tribe Oryzomyini. At least 16 of the 26 autosomal chromosome pairs of HME show conserved synteny in AMO and 17 in TNI. AMO, as in some species of the Akodon cursor group, has a highly fused karyotype, where many syntenic associations probably represent synapomorphies in this species group or, alternatively, AMO autapomorphies. A set of such associations (HME 3/25; 11/16,17; 6/21; 13,22/11; 13,22/20; 11/16,17; and, 14/19), which are also present in TNI, could represent possible synapomorphies of Akodontini. Extension of these observations to other members of the Akodontini and Oryzominyi tribes are necessary to confirm these assumptions.