Meiotic recombination plays a key role in sexual reproduction as it generates crossovers that, in combination with sister chromatid cohesion, physically connect homologous chromosomes, thereby promoting their proper segregation at the first meiotic division. Meiotic recombination is initiated by programmed double strand breaks (DSBs) catalyzed by the evolutionarily conserved, topoisomerase-like...

If strictly mitotic asexual fungi lack recombination, the conventional view predicts that they are recent derivatives from older meiotic lineages. We tested this by inferring phylogenetic relationships among closely related meiotic and strictly mitotic taxa with Aspergillus conidial (mitotic) states. Phylogenies were constructed by using DNA sequences from the mitochondrial small ribosomal subu...

Meiotic homologous recombination generates new combinations of preexisting genetic variation and is a crucial process in plant breeding. Within the last decade, our understanding of plant meiotic recombination and genome diversity has advanced considerably. Innovation in DNA sequencing technology has led to the exploration of high-resolution genetic and epigenetic information in plant genomes, ...

Meiosis is a process composed of two divisions of the germ line cells without an intervenient S phase, thus there is no duplication of DNA between the first and the second meiotic divisions. The first meiotic division begins with the pre-leptotene that is the stage where the DNA replicates and chromosomes prepare to enter the meiotic prophase I in most of the organisms with sexual reproduction ...

The budding yeast genome contains regions where meiotic recombination initiates more frequently than in others. This pattern parallels enrichment for the meiotic chromosome axis proteins Hop1 and Red1. These proteins are important for Spo11-catalyzed double strand break formation; their contribution to crossover recombination remains undefined. Using the sequence-specific VMA1-derived endonucle...

The oocyte-to-embryo transition transforms a differentiated germ cell into a totipotent zygote capable of somatic development. In C. elegans, several oocyte proteins, including the meiotic katanin subunit MEI-1 and the oocyte maturation protein OMA-1, must be degraded during this transition . Degradation of MEI-1 and OMA-1 requires the dual-specificity YAK-1-related (DYRK) kinase MBK-2 . Here, ...

In Saccharomyces cerevisiae, formation of the DNA double-strand breaks (DSBs) that initiate meiotic recombination requires the products of at least 10 genes. Spo11p is thought to be the catalytic subunit of the DNA cleaving activity, but the roles of the other proteins, and the interactions among them, are not well understood. This study demonstrates genetic and physical interactions between th...

Regular meiotic chromosome segregation requires sister centromeres to mono-orient (orient to the same pole) during the first meiotic division (meiosis I) when homologous chromosomes segregate, and to bi-orient (orient to opposite poles) during the second meiotic division (meiosis II) when sister chromatids segregate. Both orientation patterns require cohesion between sister centromeres, which i...

The behavior of meiotic chromosomes differs in several respects from that of their mitotic counterparts, resulting in the generation of genetically distinct haploid cells. This has been attributed in part to a meiosis-specific chromatin-associated protein structure, the synaptonemal complex. This complex consist of two parallel axial elements, each one associated with a pair of sister chromatid...

Centriole duplication is of crucial importance during both mitotic and male meiotic divisions, but it is currently not known whether this process is regulated differently during the two modes of division. In Caenorhabditis elegans, the kinase ZYG-1 plays an essential role in both mitotic and meiotic centriole duplication. We have found that the C-terminus of ZYG-1 is necessary and sufficient fo...