Three recessive meiotic mutants, asc(DL95), asc(DL243) and asc(DL879), were detected by the abortion of many of their ascospores and were analyzed using both cytological and genetic methods. Even though asc(DL95), asc (DL243) and the previously studied meiotic mutant, mei-1 (Smith 1975; Lu and Galeazzi (1978), complement one another in crosses, they apparently do not recombine (DeLange and Grif...

Meiosis, a specialized cell division with a single cycle of DNA replication round and two consecutive rounds of nuclear segregation, allows for the exchange of genetic material between parental chromosomes and the formation of haploid gametes. The structural maintenance of chromosome (SMC) proteins aid manipulation of chromosome structures inside cells. Eukaryotic SMC complexes include cohesin,...

Nucleate and anucleate fragments of mouse oocytes have been isolated following treatment of fully grown oocytes with cytochalasin B. The nucleate oocyte fragments resume meiosis in vitro, progressing from dictyate of the first meiotic prophase to metaphase II ('meiotic maturation'), and exhibit all of the changes in protein synthesis normally associated with meiotic maturation of mouse oocytes....

BACKGROUND During Drosophila oogenesis, unrepaired double-strand DNA breaks activate a mei-41-dependent meiotic checkpoint, which couples the progression through meiosis to specific developmental processes. This checkpoint affects the accumulation of Gurken protein, a transforming growth factor alpha-like signaling molecule, as well as the morphology of the oocyte nucleus. However, the componen...

The meiotic spindle and the zona pellucida exhibit molecular order when imaged with polarized optics. This study aimed to investigate possible factors contributing to the zona pellucida birefringence score and meiotic spindle visualization, and to evaluate whether these structures may predict intracytoplasmic sperm injection outcomes. Oocytes were divided into groups according to zona pellucida...

The life cycle of eukaryotes oscillates between a diploid and a haploid state; meiosis and fertilization alternate to generate the transitions between these states. Meiosis consists of two special rounds of cell division, preceded by a single phase of DNA replication. The most recent advances in this field were presented at the EMBO Conference on Meiosis, organized by Bernard de Massy and held ...

Meiotic drive systems are associated with low-frequency chromosomal inversions. These expected to accumulate deleterious mutations due reduced recombination and low effective population size. We test this prediction using the ‘sex-ratio’ (SR) meiotic system of Malaysian stalk-eyed fly Teleopsis dalmanni. SR is a large inversion (or inversions) on X chromosome. In particular, we study eyespan in...

background: sertoli cells play a pivotal role in creating microenvironments essential for spermatogonial stem cells (sscs) self-renewal and commitment to differentiation. maintenance of sscs and or induction of in vitro spermiogenesis may provide a therapeutic strategy to treat male infertility. objective: this study investigated the role of luekemia inhibitory factor (lif) on the propagation o...

When meiotic cells complete S phase, homologous chromosomes pair, synapse and undergo recombination. A checkpoint protein is somehow required for meiotic chromosome pairing in C. elegans, thus providing a direct link between S phase and the rest of the meiotic program.

the polygene chromosomal pattern together with the somatic and meiotic chromosomes of the autogenous tehran strain of culex pipiens molestus is described. the first and third chromosomes are metacentric, the second one is slightly submetacentric. each chromosome has well-defined, large puffed char­acteristic centromeres. randomly distributed asynaptic regions on the polytens chromosomes are ind...