Comparative study of multiple sex chromosome systems in Neotropical Primates

STEINBERG, E.R.; BRESSA, M.J.

Foz do Iguaçu

Congreso; 2018 International Congress of Genetics; 2018

Sociedad Brasilera de Genética

In Neotropical Primates (Platyrrhini: Ceboidea), the presence of multiple sex chromosomes systems (multivalents), originated from Y-autosome translocations, have been described. Among them, in males from Alouatta spp., sexual systems are formed by 3, 4 or 5 chromosomes. We analyzed blood samples and testicular biopsies from 4 males of Alouatta caraya (ACA, 2n=52, X1X1X2X2/X1X2Y1Y2), 3 males of Alouatta guariba clamitans (AGUc, 2n=46/45, X1X1X2X2X3X3/X1X2X3Y1Y2), 6 males A. pigra (API, 2n=58, X1X1X2X2/X1X2Y1Y2) and 2 males A. palliata (APA, 2n=54/53, X1X1X2X2/X1X2Y). G- and C-banding patterns confirmed the species` karyology and the meiotic studies confirmed the sexual systems. In all species air-drying technique was applied. ACA and AGU spermatocyte microspreads were prepared for analysis of synaptonemal complexes (SC), using antibodies anti-SMC3 and anti-CREST. In their early meiotic Prophase I, the sexual multivalents are fully synapsed even before the autosomal bivalents finished doing so, showing a differential behavior. In AGUc we observed 70% of early pachytene spermatocytes with the sexual pentavalent fully extended, while in ACA the sexual quadrivalent was found extended in only 20%. We compared our findings with meiotic data published for Alouatta seniculus stramineus (2n= 48, X1X1X2X2/X1X2Y1Y2), A. belzebul (2n=49, X1X1X2X2/X1X2Y) and Aotus azarae boliviensis (2n=49, X1X1X2X2/X1X2Y). We observed that early pachytene studies are scarce in the literature, including only the data on chiasmata distribution and multivalent configuration in Metaphase I and the segregation on Metaphase II. The present cytomolecular contribution enhances the knowledge of the meiotic process in Neotropical Primates and its associated variability in multiple sexual systems.