To generate cellular diversity in developing organisms while simultaneously maintaining the developmental potential of the germline, germ cells must be able to preferentially endow germline daughter cells with a cytoplasmic portion containing specialized cell fate determinants not inherited by somatic cells. In Caenorhabditis elegans, germline inheritance of the protein PIE-1 is accomplished by...

In the vast majority of sexual life cycles, fusion between single-celled gametes is directly followed by nuclear fusion, leading to a diploid zygote and a lifelong commitment between two haploid genomes. Mushroom-forming basidiomycetes differ in two key respects. First, the multicellular haploid mating partners are fertilized in their entirety, each cell being a gamete that simultaneously can b...

It has been known for more than 100 years that when spherical zygotes of the brown alga Fucus are subjected to a gradient of light, the plane of the first cell division is always perpendicular to the light axis. As illustrated in Figure 1, the resulting cell plate divides the zygote into two unequal cells; the smaller rhizoid cell emerges from the shaded portion of the gradient, whereas the lar...

The precise origins of sexual reproduction itself remain unclear (Bell 1982, Michod and Levin 1988), but the potential advantages of the genetic variation produced by sexual reproduction have been noted for almost half a century (Fisher 1958, Charnov 1982). Prime among these are the advantages to individuals, subject to changing environments, of being able to produce variable offspring through ...

It has been known for more than 100 years that when spherical zygotes of the brown alga Fucus are subjected to a gradient of light, the plane of the first cell division is always perpendicular to the light axis. As illustrated in Figure 1, the resulting cell plate divides the zygote into two unequal cells; the smaller rhizoid cell emerges from the shaded portion of the gradient, whereas the lar...

objective: to develop decision-support tools to identify patients experiencing sudden cardiac arrest (sca). methods: eighty calls related to sca were content analyzed, and the contextual patterns that emerged were organized into a checklist. two researchers independently analyzed the recorded calls and compared their findings. eighteen dispatchers scored 20 cases (which included sca and non-sca...