Homozygotes or hemizygotes are blocked or impaired
in learning, with respect to certain of the conditioning tests
used on groups of flies or larvae or on individual adults,
e.g. tests involving olfactory "shock-avoidance" learning
(Acevas-Pina and Quinn, 1979; Quinn et al, 1979), leg-shock/leg-lift learning (Booker and Quinn, 1981); "courtship
conditioning" (Gailey, Jackson, and Siegal, 1982, Genetics
102: 771-82; 1984, Genetics 106: 613-23), and habituation to
sugar stimuli when applied to tarsus (Duerr and Quinn, 1982).
When the original shock-odor testing system is modified by
redesigning the choice chamber, homozygous and hemizygous
mutants show about 60% of the control wild-type values when
tested just post-training (Tully and Quinn, 1985; Tully,
1987), but the mutant shows very rapid short-term and slower
long-term memory losses. tur/+ heterozygous females show
seemingly normal levels of shock-odor conditioned behavior
when tested immediately after training, but very rapid memory
losses (Quinn et al., 1979). Homozygous tur flies are said to
have a deficiency in (and possibly absence of) protein kinase
C (PKC) (Smith, Choi, Tully, and Quinn, 1986, Soc. Neurosci.
Abstr. 12: 399), and tur flies are almost totally deficient
in phosphorylation of a 76 kd head membrane protein which is a
major substrate for PKC (Choi, Smith, Marler, and Quinn,
1989), but the lowered PKC levels and abnormal learning do not
map to the same cytogenetic location (see cytology).