401 basepair deletion and a 6 basepair insertion, likely eliminating one of the P-loop motifs required for ATP hydrolysis, or resulting in the production of a truncated protein.
A small deletion of 401 bp in btv, in addition to a 6 bp insertion that appears to be a tandem duplication of sequences flanking one end of the deletion.
CAAGAT
abdominal lateral pentascolopidial chordotonal organ lch5 & scolopidium
btv5P1 mutants show no ciliary transport (anterograde or retrograde) Johnston's organ chordotonal neurons, as compared to controls.
Mutant aristae (unlike live wild-type aristae) vibrate in a similar way to dead aristae in the absence of external stimuli.
The arrangement and numbers of scolopidia in the abdominal lateral pentascolopidial chordotonal organs of these larvae are normal. However, these scolopidia have significant morphological defects, both in their outer dendritic segments and ciliary dilation. btv5P1 homozygous larvae have reduced touch sensitivity compared to wild-type. Locomotion in these larvae is aberrant: compared to controls they larvae are slower and pause, turn and retreat more often. These defects in locomotion arise at least partially from defective peristaltic motion: maximum larval length, stride period and % positive and negative flow are all defective. Despite their locomoter defects, these larvae exhibit normal phototaxic behaviour.
In wild-type animals, the antennal receiver moves in a non-linear fashion in response to sound. In the absence of sound the receiver oscillates spontaneously. Both Nonlinearity and spontaneous oscillations are absent in mutant animals. fRs ~ 539 Hz. In mutants the dendritic cilia of auditory mechanosensory neurons display an anatomically aberrant ciliary dilation, the contact zone between ciliary axoneme and membrane.
Mutant males demonstrate vigorous courtship including courtship songs. 50% of mutant males use both of their wings simultaneously during courtship song production (in contrast to wild-type males which vibrate only one wing at a time). Mutant males fully twist the vibrating wing so that the ventral surface is directed forward (90o angle of attack), whereas wild-type males only twist the vibrating wing so the trailing edge is slightly lower. Pulse duration is significantly longer than wild-type in mutant male songs and the carrier frequency of the sine song is significantly higher than normal. Relative amplitude of the sine song is higher than normal in mutant males.
Mutants show reduction in sound-evoked courtship behavior. The sound evoked response (measured via the antennal nerve) is virtually eliminated. Mechanoreceptor potentials recorded from thoracic macrochaete bristles are normal. Homozygous or hemizygous males have motile sperm and are fertile.
Audiograms demonstrate mutants show a reduced response at all sound intensity. Mutants respond abnormally in an olfactory behaviour test. 6/20 males successfully copulate with females within 30 minutes. Males are fertile with wild type sperm motility. Adults are very sedentary, often remaining at the bottom of the vial.
