Worm Breeder's Gazette 3(2): 22

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Male Development

J. Sulston, D. Albertson, N. Thomson

The development of the male has been followed to maturity, and the 
fates of the cells produced by the post-embryonic lineages are now 
known.  Here are a few of the novel points.
1.  Sensory rays.
The nine pairs of sensory rays are composed of three cells: two 
neurons and a sheath cell.  These sensilla are the only structures in 
the tail for which there is a clear repeating pattern of cell 
2.  Formation of the cloaca and spicules.
Daughters of the B cell make up the spicules, each composed of 2 
neurons, 4 socket cells and 2 sheath cells.  Other cells form the 
spicule channels and a neuron with striated rootlet that lies over the 
base of the spicule and probably is a proprioceptor.
The elongated shape of the spicules and cloaca is obtained by the 
dorsal spicule retractor muscles which attach to the dorsal edge of 
the cloaca and crawl anteriorly.  In their absence the cloaca is short 
and the spicules are crumpled.
3.  Rearrangement of the anal depressor muscle.
During L4 lethargus, the myofilaments of the depressor muscle detach 
dorsally and rotate through 90  before reattaching to the gubernaculum.
The function of the muscle is thereby completely altered.  In the 
absence of post-embryonic muscle the rearrangement is incomplete: some 
filaments run in each direction.
4.  Regulation.
Cell ablations (by laser microbeam) in the young L1 have revealed 
some capacity for regulation in two areas.  (a) Rays are ordinarily 
made by V5(one), V6(five) and T (three).  After ablation of V6, V5 can 
make most of the rays normally produced by V6.  After ablation of V5 
and V6, V4 can make one or two rays.  Other V cells have not been seen 
to produce rays, perhaps because they arrive at the tail too late, but 
V3 was stimulated to go through an extra round of division.  (b) Extra 
neurons, supporting cells and hypodermal cells are added to the 
preanal ganglion, normally by division of P10.p and P11.p.  After 
ablation of P10.p or P11.p, P9.p can be recruited to this function; 
the resulting animal is perfect except for the trivial loss of a 
ventral hypodermal nucleus.  No other cell has ever been recruited.