Sex determination and sperm morphology in Cebidae

STEINBERG, ELIANA R.; PALERMO, ANA M.; NIEVES, MARIELA; BURNA, ALEXIS; SOLÍS, GUSTAVO; ZUNINO, GABRIEL E.; MUDRY, MARTA D.

Porto Alegre, Brasil

Congreso; 11 Congreso brasilero de Primatologia; 2005

Sociedade Brasileira de Primatologia

Karyotype and comparative karyology are useful parameters in reproductive research as well as in systematic and evolutionary biology. The sexual determination pattern is an important tool in  any breeding project. The use of this parameter will be an invaluable improvement for primate conservation in zoological gardens and breeding centres. In this work, we describe Saimiri boliviensisLs sexual system and sperm morphology, both using the Environmental Scanning Electron Microscope (ESEM) and the optic microscope (OM). We compare them with previously chromosomal published data of other Ceboidea. For the meiotic and spermatic studies, testicular biopsies were taken from 4 specimens in captivity at EBCo, in Argentina. At least 50 spermatozoa per specimen were measured by ESEM and OM. Simultaneously, mitotic studies from blood samples were performed from each specimen. All animals were weighted and the testicular volume was measured. The body weight during the breeding season was 930.0 } 0.5 gr, with a testicular volume of 4.67 } 8x10-4 cm3. The spermatozoa proportions measured by OM were: total length: 71.39 } 0.45 ƒÊm: head length: 5.71 } 0.45 ƒÊm; head width: 3.76 } 0.45 ƒÊm;  acrosome length: 3.70 } 0.45 ƒÊm; midpiece length: 12..20 } 0.45 ƒÊm; tail lenght: 65.68 } 0.45 ƒÊm,  all in agreement with the ones determined by ESEM. The presence of a distinctive XY bivalent was observed in diacinesis/metaphase I. The 22 bivalents observed corresponded to a 2N = 44, XY. The G banding pattern is in agreement with specimens of both sexes previously published as S. boliviensis. This XY pattern was also observed in Cebus apella paraguayanus and Ateles paniscus, in contrast with different multiple sex determination systems found in Alouatta caraya or Aotus azarai. We discuss these findings in the framework of different Ceboidea genera in order to propose a phylogeny involving these characters. (Grants PIP-CONICET 2450, UBACyT X031, Sigma Xi 3040277).