BRAIN AND BEHAVIOR: THE ROLE OF THE FRUITLESS GENE IN COMPLEX BEHAVIOR IN DROSOPHILA

Whitney HumphreyDr. Barbara TaylorHHMI 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 GENETICSIn 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

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

Deficiencies Fru3, Fru4

(P-element inserts)

Fru1

(Inversion)

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 on21:00 - 8:59 – Lights off

ACTIVITY OF WILDTYPE MALES

9:0010:

1511:

3012:

4514:

0015:

1516:

3017:

4519:

0020:

1521:

3022:

45 0:00

1:15

2:30

3:45

5:00

6:15

7:30

8:45

0

10

20

30

40

50

60 CSA Average Activity vs. Time

Time

Aver

age

Coun

ts

Individual Raw Data

Lights on Lights off

n = 20

DO FRU HYPOMORPHS MALES HAVE WILDTYPE ACTIVITY CYCLES?

9:0011:

0013:

0015:

0017:

0019:

0021:

0023:

00 1:00

3:00

5:00

7:00

9:00

0102030405060fru1 Average Activ-

ity vs. Time

Time

Aver

age

Activ

ity

9:0011:

3014:

0016:

3019:

0021:

30 0:00

2:30

5:00

7:30

0102030405060

CSA Average Activity vs. Time

Time

Aver

age

Coun

ts

9:0011:

0013:

0015:

0017:

0019:

0021:

0023:

00 1:00

3:00

5:00

7:00

9:00

0204060

fru4 to1 Average Activity

Time

Activ

ity

9:0010:

4512:

3014:

1516:

0017:

4519:

3021:

1523:

000:452:3

04:1

56:0

07:4

50

204060

fru4tocs Average Activity vs Time

Time

Activ

ity

n = 20

n = 10n = 10

FRUM NULL MUTANTS HAVE WILDTYPE ACTIVITY CYCLES

9:0010:

3012:

0013:

3015:

0016:

3018:

0019:

3021:

0022:

300:001:3

03:0

04:3

06:0

07:3

09:0

00

102030405060

fru440 x frusat15 Av-erage Activity

TimeAc

tivity

9:0010:

3012:

0013:

3015:

0016:

3018:

0019:

3021:

0022:

300:001:3

03:0

04:3

06:0

07:3

09:0

00

102030405060

fru440 x P14 Average Activity

Time

Activ

ity

n = 12n = 12

CIRCADIAN RHYTHM A roughly-24-hour cycle in the

biochemical, physiological or behavioral processes.

CSA

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 sex-specific 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