In most sexually reproducing organisms, the fundamental process of meiosis is implemented concurrently with two differentiation programs that occur at different rates and generate distinct cell types, sperm and oocytes. However, little is known about how the meiotic program is influenced by such contrasting developmental programs. Here we present a detailed timeline of late meiotic prophase dur...

Progression through meiotic prophase is associated with dramatic changes in chromosome condensation. Two proteins that have been implicated in effecting these changes are the mammalian HP1-like protein M31 (HP1beta or MOD1) and the unusual core histone macroH2A1.2. Previous analyses of M31 and macroH2A1.2 localisation in mouse testis sections have indicated that both proteins are components of ...

Spermatogenic cells synthesize a unique 70-kDa heat shock protein (HSP70-2) during prophase of meiosis I, and targeted disruption of the Hsp70-2 gene has shown that this protein is required for spermatogenic cell differentiation in adult mice. HSP70-2 is associated with synaptonemal complexes formed between paired homologous chromosomes during meiotic prophase. The present study focuses on the ...

Cytological analysis under light microscopy of the single hybrid P30R50 of silage corn revealed an abnormal pattern of microsporogenesis that affected the meiotic products. Meiosis progressed normally until diakinesis, but before migration to the metaphase plate, bivalents underwent total desynapsis and 20 univalent chromosomes were scattered in the cytoplasm. At this stage, meiocytes also...

The HSP70 heat-shock proteins are molecular chaperones that assist other proteins in their folding, transport and assembly into complexes. Most of these proteins are either constitutively expressed or their expression is induced by heat shock and other stresses. However, two members of the Hsp70 family (HSP70-2 and HSC70T in mice) are regulated developmentally and expressed specifically in sper...

Interlocked bivalents at 1st meiotic metaphase are relatively uncommon in spermatocytes of the newt Triturus vulgaris, but their frequency of occurrence can be significantly increased by subjecting newts to a 24-h heat shock. Newt spermatocytes are sensitive to a heart shock at any stage between the end of premeiotic S and mid to late pachytene. The heat shock does not cause evidence desynapsis...

the genus onobrychis belongs to family fabaceae and has about 130 species throughout the world. onobrychis sect. hymenobrychis with nearly 14 species in iran is one of the important sections of the genus. the chromosome number and meiotic behaviour were studied in two populations of onobrychis chorassanica belonging to this section native to iran. this report is the first cytogenetic analysis o...

The correct sequence of meiotic prophase development in the male mouse has been established by the use of pubertal males. The first wave of spermatogenesis at this time provides a unique opportunity to study progressive meiotic development in a direct way. Air-dried and micro-spread analyses have been carried out. Temporal and morphological progression at this time is entirely consistent with t...

Synaptic mutants are the subject of a special concern to cytologists and geneticists as they hold the variability in their recombination pattern. Seeds of Trachyspermum ammi (L.) Sprague (ajwain) were treated with Ethyl Methane Sulphonate (EMS) solution at 3 different concentrations viz. 0.1%, 0.3% and 0.5% for 5 h, prepared in potassium phosphate buffer with 7.0 pH. During meiotic observation ...