BRAIN AND BEHAVIOR: THE ROLE OF THE
FRUITLESS GENE IN COMPLEX BEHAVIOR
IN DROSOPHILA
Whitney Humphrey
Dr. Barbara Taylor
HHMI Summer Program
RELEVANCE OF WORK
Understanding of the interaction between the
central nervous system and behavior.
 Neurological diseases in humans
 Sex Determination and Sexual Orientation in
flies

DROSOPHILA MELANOGASTER

Ideal model organisms for studying genetics
 Short
generation time
 Many strains exists
SEX-SPECIFIC BEHAVIORAL DIFFERENCES IN
DROSOPHILA
Courtship
Aggression
MALE VS. FEMALE GENETICS
In females, a cascade is
initiated and through
splicing events produce a
female-specific transcript
encoding a female-specific
protein:
-DoublesexF (DsxF)
In males, a cascade is initiated
but different splicing events
produce male-specific transcripts
encoding male-specific proteins:
-FruitlessM (FruM)
-DoublesexM (DsxM)
IN FRU MUTANTS, MALE BEHAVIOR IS ALTERED
Deficiencies
Fru3, Fru4
(P-element inserts)
Fru1
(Inversion)
Expected behavior:
-Males court females
-Production of song
-Copulation
Unexpected behavior:
-Female-male courtship
interrupted
-Male-male courtship observed
-This event is referred to as
chaining.
-May or may not be song but
copulation does not occur
AVERAGE ACTIVITY LEVELS FOR CANTONS FLIES
DL Cycle: 12-hours lights on, 12-hours lights off
Males: Anticipate lights on and have very little activity during the day (siesta)
Females: Do not anticipate lights on and do not take a siesta.
THE DROSOPHILA ACTIVITY MONITOR
How we measure activity:
The DL cycle:
9:00 - 20:59 – Lights on
21:00 - 8:59 – Lights off
9:00
Lights on
Time
Lights off
n = 20
9:00
8:00
7:00
6:00
5:00
4:00
3:00
2:00
1:00
0:00
23:00
22:00
21:00
20:00
19:00
18:00
17:00
16:00
15:00
14:00
60
13:00
12:00
11:00
Individual Raw Data
10:00
Average Counts
ACTIVITY OF WILDTYPE MALES
CSA Average Activity vs. Time
50
40
30
20
10
0
9:00
10:30
12:00
13:30
15:00
16:30
18:00
19:30
21:00
22:30
0:00
1:30
3:00
4:30
6:00
7:30
9:00
9:00
10:30
12:00
13:30
15:00
16:30
18:00
19:30
21:00
22:30
0:00
1:30
3:00
4:30
6:00
7:30
9:00
Activity
60
50
40
30
20
10
0
Activity
60
50
40
30
20
10
0
Average Activity
CSA Average Activity vs. Time
n = 10
9:00
10:30
12:00
13:30
15:00
16:30
18:00
19:30
21:00
22:30
0:00
1:30
3:00
4:30
6:00
7:30
9:00
9:00
10:45
12:30
14:15
16:00
17:45
19:30
21:15
23:00
0:45
2:30
4:15
6:00
7:45
Average Counts
DO FRU HYPOMORPHS MALES HAVE WILDTYPE
ACTIVITY CYCLES?
fru Average Activity vs.
1
60
fru4tocs Average Activity vs
Time
50
Time
40
30
20
10
0
Time
Time
n = 20
fru4 to1 Average Activity
60
50
40
30
20
10
0
Time
Time
n = 10
9:00
10:15
11:30
12:45
14:00
15:15
16:30
17:45
19:00
20:15
21:30
22:45
0:00
1:15
2:30
3:45
5:00
6:15
7:30
8:45
9:00
10:15
11:30
12:45
14:00
15:15
16:30
17:45
19:00
20:15
21:30
22:45
0:00
1:15
2:30
3:45
5:00
6:15
7:30
8:45
Activity
30
Activity
FRUM NULL
MUTANTS HAVE WILDTYPE ACTIVITY
CYCLES
fru440 x P14 Average Activity
n = 12
fru440 x frusat15 Average Activity
60
60
50
50
40
40
30
20
20
10
10
0
0
Time
Time
n = 12
CIRCADIAN RHYTHM

A roughly-24-hour cycle in the biochemical,
physiological or behavioral processes.
CS
A
Fru440 x Frusat15
CONCLUSION
Initially, we investigated if mutations in fruitless
affected the male pattern of activity in flies.
 We conclude that fruitless does not affect sexspecific activity cycles.

 However,
fruitless mutants show levels of
decreased activity.

We also discovered that the fruitless mutants
with deficiencies did not have a 24-hour period.
ACKNOWLEDGMENTS
Dr. Barbara Taylor
 Dr. Jaga Giebultowicz
 Will Gibson
 Eileen Chow
 Dr. Kevin Ahern
 HHMI Summer Undergraduate Research
Program
