hypomorphic allele - genetic evidence
P{lacZ}HGTXP-JG is inserted 4kb downstream of HGTX.
larval intersegmental nerve | embryonic stage 16 (with HGTXD25)
In stage 16 HGTXD25/HGTXP-JG embryos, both secondary branches of the intersegmental nerve (anterior fascicle), ISNb and ISNd, are absent in a significant proportion of hemisegments.