Table 2.

Activity rhythms of flies expressing PER and TIM

Genotype No. of copies PER n (No. of rhythmic) Average period + SEM %Rhythmic
Locomotor data from Per 1 lines per01/per01 background Per 1-A/+ P 46 (24) 21.69 ± 0.84* 52.2
Per 1-A/Per 1-A PP 39 (24) 22.38 ± 0.11* 61.5
Per 1-B/+ P 16 (14) 22.43 ± 0.10* 87.5
Per 1-B/Per 1-B PP 58 (12) 22.54 ± 0.18* 20.7
per+/per+ background +/+ (Per 1-A siblings) ++ 28 (26) 23.58 ± 0.09 92.9
Per 1-A/+ ++P 85 (77) 22.39 ± 0.05* 90.6
+/+ (Per 1-B siblings) ++ 32 (29) 23.53 ± 0.07 90.6
Per 1-B/+ ++P 72 (67) 22.68 ± 0.07* 93.1
Per 1-B/Per 1-B ++PP 32 (10) 22.10 ± 0.16* 31.3
Locomotor data from Per 1 × Tim 4 lines per+/per+, tim+/tim+ Background Per 1-A × Tim 4-7 PT 97 (82) 22.79 ± 0.07* 84.5
PTT 122 (84) 22.68 ± 0.06* 68.9
PPT 19 (12) 22.38 ± 0.24* 63.2
PPTT 20 (9) 22.28 ± 0.15* 45.0
Per 1-B × Tim 4-7 PT 52 (49) 22.65 ± 0.06* 94.2
PTT 78 (66) 22.27 ± 0.07* 84.6
PPT 64 (8) 21.69 ± 0.25* 12.5
PPTT 62 (8) 21.94 ± 0.31* 12.9
  • Increased PER, but not TIM, affects period length. To measure locomotor activity, flies were placed in locomotor activity monitors under constant conditions at 25°C for 7 d. The endogenous per gene is on the X chromosome. In males, per is dosage compensated, such that the effect of one per copy in males is equivalent to two in females. We count it here as two copies. P represents one copy of Per 1; T represents one copy of Tim 4-7. + represents one copy of endogenous per. Although it is not indicated in the bottom of the Table with a +, all flies in Per 1 × Tim 4 lines had endogenous per and tim. An asterisk indicates that the average period of this genotype is significantly different from its nontransgenic siblings (p < 0.05; Student's t test). Note: The wild-type Per 1-A stock developed a spontaneous independent mutation that significantly reduced the viability of this line, making it difficult to obtain reliable locomotor data from homozygous flies. There was a significant effect of PER on period length in the Per 1 × Tim 4 lines when measured by two-way ANOVA (p < 0.000), but not of TIM in the same lines (p = 0.53). Thus, additional TIM in the circadian system does not significantly alter period.