Meiotic Pairing and Segregation of Achiasmate Sex Chromosomes in Eutherian Mammals: The Role of SYCP3 Protein

• DOI: 10.1371/journal.pgen.0030198
• Publication Date: 2007-10-29T20:27:07Z
• Authors: Roberto de la Fuente; María Teresa Parra; Alberto Viera; Adela Calvente; Rocío Gómez; José Ángel Suja; Julio S Rufas; Jesús Page
• Keywords: Synaptonemal complex; Chromosomal crossover; Synapsis; Heterogametic sex; Chromosome 3; Pseudoautosomal region

In most eutherian mammals, sex chromosomes synapse and recombine during male meiosis in a small region called pseudoautosomal region. However some species do not synapse, how these manage to ensure their proper segregation is under discussion. Here we present study of the meiotic structure behavior one species, Mongolian gerbil (Meriones unguiculatus). We have analyzed location synaptonemal complex (SC) proteins SYCP1 SYCP3, as well three involved process recombination (RAD51, MLH1, γ-H2AX). Our results show that although X Y are associated at pachytene form body, axial elements (AEs) contact, they never assemble SC central element. Furthermore, MLH1 detected on AEs chromosomes, indicating absence reciprocal recombination. At diplotene organization changes strikingly, associate end end, SYCP3 forms an intricate network occupies chromosome distal long arm. Both association maintained until metaphase I. anaphase I migrate opposite poles, but filaments connecting both observed. Hence, can assume modifications from onwards correlated with maintenance association. These demonstrate components may participate achiasmate mammals.