A nematode having null mutations in hop 1 and sel 12, said {HEAD ~ nematode} having {TAIL ~ a combined maternal effect embryonic lethality} and egg laying defective phenotype, at least one of said mutations being introduced by artifice, wherein said nematode is a C. elegans nematode 
having
A nematode having null mutations in hop 1 and sel 12 , said { HEAD ~ nematode } having { TAIL ~ a combined maternal effect embryonic lethality } and egg laying defective phenotype , at least one of said mutations being introduced by artifice , wherein said nematode is a C. elegans nematode
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH