"Synaptic behavior and chromatin remodeling ofthe multiple sex chromosomes in bats"

IM RAHN; R NORONHA; A BARAJAS; C NAGAMASCHI; J PIECZARKA; A J SOLARI; R SCIURANO

Ischia

Congreso; "21st INTERNATIONAL COLLOQUIUM ON ANIMAL CYTOGENETICS AND GENE MAPPING (21st ICACGM)"; 2014

Associated to the Institute for Animal Production Systems in Mediterranean Environments (ISPAAM), National Research Council (CNR) of Italy,

The usual sex-chromosome system among eutherian mammals is XX/XY. However, many exceptions from this general pattern were discovered. One of these sex-chromosome mechanisms is the multiple sex-chromosome system, which is evolutionary-fixed among many bat species of the family Phyllostomidae, and has arisen by a translocation between one original gonosome (X or Y chromosome), and an autosome, giving rise to a ?Neo-XY body?. The aim of this work is to study the synaptic behavior and chromatin remodeling of multiple sex chromosomes in different species of phyllostomids. Testicular tissues from adult males of the species Artibeus lituratus, A. planirostris, Uroderma bilobatum and Vampyrodes caraccioli are analyzed by optical/electron microscopy and immunofluorescence of meiotic proteins involved in synapsis (SYCP3, SYCE3), sister-chromatids cohesion (SMC3), early recombination (RAD51) and chromatin silencing (BRCA1, γ-H2AX). The common features shared by all of them are the presence of RAD51, BRCA1 and -H2AX-labelled chromatin domains on asynaptic regions of rearranged chromosomes. The presence of asynaptic segments throughout pachynema in many species of phyllostomids- that are fertile with normal spermatogenesis-, contradicts the claim that silent asynaptic autosomal segments necessarily lead to spermatogenic impairment as it is known in humans.