Sex Determination

Question 1

Bipotential Gonad - Male

Answer 1

• Testosterone
• Anti-Mullerian duct hormone
• no mullerian duct
• wolffian duct –> vas deferens

Question 2

Bipotential Gonad - Female

Answer 2

• No Testosterone
• No Anti-Mullerian duct hormone
• mullerian duct –> oviduct
• no wolffian duct

Question 3

Gential Development

Answer 3

Androgens = Male

No Androgens = Female

Question 4

Androgen Insensitivity Syndrome

Answer 4

• androgens secreted (testes)
• androgen receptor inactive (female genitals develop)
• testes + lower portion of mullerian duct

Question 5

Primary Sex Determination

Answer 5

Heterogametic systems – XX/XY
Fly – X/XX
Insect – 1n/2n

Temperature gated and Social Systems
- turtle + clownfish

Question 6

Turner’s Syndrome

Answer 6

Female with one X chromosome

– female NOT determined by 2 X chromosomes

Question 7

Sex Reversal

Answer 7

Males

• translocation of sex-reversal from Y to X
• encodes TF –> secrete androgens

Females
- deletion of sex-reversal

Question 8

Lack of Y

Answer 8

Male with no Y chromosome

– male NOT determined by Y chromosome

Question 9

Drosophila Sex Determination - Male

Answer 9

• X:A = 0.5
• no SXL protein (no TF to bind to promoter)
• U2AF binds to male 3’ss
• no TRA expressed (stop codon)
• Tra2 spliced
• DSXm expressed (suppress female differentiation)

Question 10

Drosophila Sex Determination - Female

Answer 10

• X:A = 1.0
• SXL protein (TF to bind to promoter)
• U2AF further 3’ss
• TRA expressed
• Tra2tra spliced
• DSXf expressed (suppress male differentiation)

Question 11

Behaviour of Organisms

Answer 11

• responses to stimuli
• chemotaxis
• mating pheromones

Question 12

Drosophila Courtship Behaviour - Female

Answer 12

2X:2A –> SXL –> TRA + TRA2 –> DSXf

- no fruitless produced
- have TRA2 binding site after spliced
remove TRA2 binding site = female has male courtship

Question 13

Drosophila Courtship Behaviour - Male

Answer 13

1X:2A –> no SXL –> no TRA
TRA2 –> DSXm
TRA2 –> fru

• fruitless produced = male courtship behaviour
• no TRA2 binding site after spliced

Question 14

Neurons Action Potential

Answer 14

• normally = -70mV
  BLUE LIGHT
• depolarization = above 0mV
  (opsin opens, ions flow)

Question 15

Two Component System

Answer 15

GAL4 driver line –> GAL4 –> binds to UASGAL4
Activates YFG

• YFG w/ GFP = visualize neurons
• YFG w/ TRP = temp sensitive ion pore (behaviour)
• YFG w/ Tetx = inhibit neural transmitter release