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General Information
D. melanogaster
FlyBase ID
Feature type
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
Key Links
Nature of the Allele
Mutations Mapped to the Genome
Additional Notes
Nucleotide change:


Amino acid change:

V243D | per-PA; V243D | per-PB

Reported amino acid change:



Site of nucleotide substitution in mutant inferred by FlyBase based on reported amino acid change.

Associated Sequence Data
DNA sequence
Protein sequence
Progenitor genotype
Nature of the lesion

The missense mutation falls in the PAS domain.

Amino acid replacement: V243D. V243 lies in a conserved hydrophobic region just N-terminal to the first PAS repeat.

Nucleotide substitution.

Nucleotide substitution: T3629A.

Missense mutation.

Nucleotide substitution: T?A. Amino acid replacement: V245D. Mutation is in exon 3.

Expression Data
Reporter Expression
Additional Information
Marker for
Reflects expression of
Reporter construct used in assay
Human Disease Associations
Disease Ontology (DO) Annotations
Models Based on Experimental Evidence ( 0 )
Modifiers Based on Experimental Evidence ( 0 )
Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
Disease-implicated variant(s)
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description

perL1 mutant adults have their longest daytime sleep bout significantly later than controls.

Majority of perL1 mutant adults show a distinct ultradian rhythmicity in walking activity under constant light conditions, which however is not significantly different from that exhibited by wild-type flies. perL1 flies do not show ultradian rhythmicity in walking under constant dark conditions.

perL1 mutants exhibit period lengths than are not temperature compensated and that lengthen with higher temperatures.

Mutant flies have locomotor activity rhythms with 28.1 hour periods (longer than wild type) when the free running period is determined in constant darkness conditions at 25[o]C after 4 days of 12 hour light: 12 hour dark conditions.

Under constant darkness conditions at 25[o]C, flies show rhythmic locomotor activity, but the period is longer than the wild-type period length (29.0 +/- 0.6 hours compared to 24.0 +/- 0.1 hours respectively).

The evening peak of activity occurs later than normal in mutant flies under 12 hour light: 12 hour dark conditions.

Mutant flies have a circadian locomotor activity period of 29.6 +/- 0.1 hours (compared to 23.6 +/- 0.1 hours for wild-type flies).

Shows a temperature compensation defect in that average period differs by 2.3hr between 20oC and 29oC.

perL1 flies show normal initial behavioural response to cocaine exposure, but not sensitization to a subsequent exposure.

The period of the interpulse interval (IPI) of the male courtship song is 72.0 seconds (wild-type value is 67.9 seconds).

Mean courtship bout duration in perL1 males is not significantly different from that of wild-type males.

19% of flies are arrhythmic with respect to locomotor activity under constant darkness conditions. The period of activity is 28.8 +/- 0.2 hours (longer than wild-type flies).

Homozygous flies show nocturnal activity rhythm at both 25oC and 30oC under 12 hour light:12 hour dark conditions. Flies show clear freerunning locomotor activity rhythms under constant darkness. The freerunning period decreases significantly with decreased temperature, in contrast to wild-type flies which show little change in freerunning period with increased temperature. Locomotor rhythms can be entrained to temperature cycles under constant lighting conditions, but the entrainability is reduced compared to wild-type flies.

Circadian period is 29 hours.

Lengthen circadian rhythms.

Free running period of 29.6 hours.

Mutation has no effect on larval heartbeat.

Lengthens the free-running period of the locomotor activity rhythm from 24 to 28.5 hours under constant darkness.

No larvae exhibit appreciable diel rhythms under cycling conditions of light or temperature. Larvae are also not rhythmic under free-running conditions.

Mutants display long circadian rhythm and males produce long song rhythms. This genetic coupling found in males does not extend to females, females have a preference for wild type courtship song over the mutant long song rhythm.

Long cycle duration, the evening peak of activity is shifted to a later time than wild type.

Evening activity peak is shifted to an later time in light-dark regimes.

Males perform poorly in conditioned inhibition of courtship toward females but males learn normally when they were exposed longer to females during training. Males also suppress their courtship of immature males.

Measures of acquisition at intermediate and maximum levels and of 30 min memory retention are normal. Mean Courtship Index (CI) for males exposed to fertilised females for 30 mins does not differ significantly from control males with no courtship experience or after exposure to other fertilised females. After 30 mins exposure of an immature male to another immature male a significantly suppressed response to another immature male is observed. P{per13.2} and P{per14.6} transgenic flies have long-period phenotypes.

The activity rhythm period of perL1/Y flies is lengthened by CkIIβAnd, by 1.6 hours.

Pupal and larval stages are lengthened. The circadian locomotor activity rhythms of adults exhibit 28-30 hour periodicities at 25oC. At lower temperatures in constant darkness adults exhibited shortened periodicities, at higher temperatures the periodicities were lengthened. In conditions of cycling light (12h light and 12h darkness) the pacemaker can be reset to exhibit 24h rhythmicity and the 'evening peaks' of locomotor activity are in the evening.

perL1 larvae develop significantly more slowly than wild-type larvae. perL1 flies eclose significantly more slowly than wild-type flies.

Individuals have longer circadian rhythms than wild type, eclosion profiles remain arrhythmic under a light dark cyle but can be entrained to a temperature cycle (Konopka, PhD Thesis, Pasadena). The effect on circadian behaviour is matched by the effect on the song cycle, a long 80 sec lovesong cycle (Kyriacou and Hall, Anim Behav 37:850 ). Flies develop slower than wild type under a variety of environmental conditions when the circadian behaviour is arrhythmic (Kyriacou, Heredity, in press). Males show defective courtship conditioning (Jackson, J. Comp. Phys. A 151: 545).

The average period of locomotor activity rhythm decreases with decreasing temperature. The period decreases by about 1.0 hour when perL1 flies are transferred to constant infrared light after 10 days of constant light. The light intensity threshold for maximum lengthening of the period and production of arrhythmia is decreased compared to wild-type.

Mutants show reduced activity of Tdc gene product.

circadian rhythms; long period adults stain poorly with anti-PER antibody (Siwicki, Eastman, Petersen, Rosbasch and Hall, 1988)

External Data
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Enhanced by
Suppressed by

perL1 has abnormal circadian rhythm phenotype, suppressible by dcoS

NOT suppressed by

perL1 has abnormal circadian rhythm phenotype, non-suppressible by dcoS

Enhancer of
Phenotype Manifest In
Enhanced by

perL1 has phenotype, enhanceable by timrit

Suppressed by

perL1 has phenotype, suppressible by timSL

Enhancer of

perL1 is an enhancer of phenotype of timrit

Additional Comments
Genetic Interactions

perL1 ; CkIIαTik/+ flies have a circadian locomotor activity period of 32.5 +/- 0.1 hours (compared to 23.6 +/- 0.1 hours for wild-type flies).

Long circadian period of perL1 is suppressed by dcoS but the failure of temperature compensation of perL1 is not.

perL1;timUL flies have a circadian period lengths of about 41.3 hours.

perL1, timrit double mutants show a period length of 32.9hr at 24oC, which exceeds that expected for the summation of the individual effects. At 27oC the period is 44.4hr.

timSL can shorten the rhythm to 26 hours in perL1 mutants. timSL can also shorten the time of eclosion.

Xenogenetic Interactions
Complementation and Rescue Data
Fails to complement
Images (0)
Stocks (1)
Notes on Origin

Konopka, Benzer.


Long cycle period.

Long period mutation, cycles are not affected by expression of P{rh-per}.

per nuclear translocation in pacemaker neurons is delayed compared to wild type, this delay is temperature sensitive.

External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (6)
Reported As
Symbol Synonym
Name Synonyms
Secondary FlyBase IDs
    References (109)