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