Polytene chromosomes normal.
Mutant embryos do not respond to injected purified polarizing activity (spz).
Incompletely penetrant dominant dorsalization.
Perivitelline fluid from embryos laid by Tlrv13 spz4/Tlrv4 spz2 females does not show axis-inducing activity when injected into the perivitelline space of embryos derived from pip1/pip2 females. Perivitelline fluid from embryos laid by Tlrv13/Tlrv19 females shows polarising activity when injected into the perivitelline space of embryos derived from pip1/pip2 females.
Revertant.
Injection of spz into Tl- embryos does not cause rapid degradation of cact.