Anaphase

In C. elegans, anaphase is comprised of two separable components, anaphase A, where the chromosomes separate from each other before any chromosome to pole movement, and anaphase B, where the spindle poles move away from each other, with the concomitant movement of the chromosomes to the poles. During anaphase B, the movement of the spindles, which carry the chromosomes, occurs through a combination of pulling and pushing forces. Cortical forces attached at the centrosomes pull the microtubule asters away from one another, while central spindle forces from overlapping microtubule arrays that had formed between separating chromosomes, push the chromosomes away from one another. The holocentric nature of C. elegans chromosomes entails special consideration to ensure the forces at all of the microtubule attachment sites of the chromosome are coordinated so that shearing of the chromosome during segregation does not occur.

Hedgehog signaling

A conserved regulatory cascade that is important in vertebrates and Drosophila for patterning and cell proliferation during development. The main components in this pathway are Hedgehog (Hh), mammalian Sonic hedgehog (Shh), skinny hedgehog (Ski), dispatched (Disp), patched (Ptch), and Smoothened (Smo). C. elegans lacks true Hh and Smo orthologs; however, it does have orthologs of Ski, Disp, and Ptch along with multiple hegdgehog-related (Hh-r), Patched (PTC) and patched-related (PTR) genes.

Ray development

C. elegans male tail contains four types of male-specific sensilla, the most prominent of which are the rays. These 18 sensory rays convey mechano- and chemosensory information critical to male mating. Each ray is composed of three cells: RnA: A-type sensory neuron; RnB: B-type sensory neuron; and Rnst: ray structural cell, which are derived from one neuroblast, the ray precursor cell called Rn. Each ray is morphologically and molecularly distinct from each other. Most all ray identity follows a determinate cell lineage model where cell identity is established based on the pattern of cell division; ray 5 does require external cues from a TGF-beta signalling pathway to adopt its final fate.