Sex Determination Flashcards
Bipotential Gonad - Male
- Testosterone
- Anti-Mullerian duct hormone
- no mullerian duct
- wolffian duct –> vas deferens
Bipotential Gonad - Female
- No Testosterone
- No Anti-Mullerian duct hormone
- mullerian duct –> oviduct
- no wolffian duct
Gential Development
Androgens = Male
No Androgens = Female
Androgen Insensitivity Syndrome
- androgens secreted (testes)
- androgen receptor inactive (female genitals develop)
- testes + lower portion of mullerian duct
Primary Sex Determination
Heterogametic systems – XX/XY
Fly – X/XX
Insect – 1n/2n
Temperature gated and Social Systems
- turtle + clownfish
Turner’s Syndrome
Female with one X chromosome
– female NOT determined by 2 X chromosomes
Sex Reversal
Males
- translocation of sex-reversal from Y to X
- encodes TF –> secrete androgens
Females
- deletion of sex-reversal
Lack of Y
Male with no Y chromosome
– male NOT determined by Y chromosome
Drosophila Sex Determination - Male
- 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)
Drosophila Sex Determination - Female
- X:A = 1.0
- SXL protein (TF to bind to promoter)
- U2AF further 3’ss
- TRA expressed
- Tra2tra spliced
- DSXf expressed (suppress male differentiation)
Behaviour of Organisms
- responses to stimuli
- chemotaxis
- mating pheromones
Drosophila Courtship Behaviour - Female
2X:2A –> SXL –> TRA + TRA2 –> DSXf
- no fruitless produced
- have TRA2 binding site after spliced
remove TRA2 binding site = female has male courtship
Drosophila Courtship Behaviour - Male
1X:2A –> no SXL –> no TRA
TRA2 –> DSXm
TRA2 –> fru
- fruitless produced = male courtship behaviour
- no TRA2 binding site after spliced
Neurons Action Potential
- normally = -70mV
BLUE LIGHT - depolarization = above 0mV
(opsin opens, ions flow)
Two Component System
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