Sex Determination and Gonad Formation Flashcards
(20 cards)
What is the genetic determinant of sex in mammals?
Presence or absence of SRY gene
Where does gonad formation begin?
At the genital ridge (intermediate mesoderm)
What cells express SRY?
Pre-Sertoli cells
What does SRY activate?
Sox9
What does Sox9 do?
Promotes testis development and represses ovarian genes
What hormone do Sertoli cells produce?
AMH (Anti-Müllerian Hormone)
What does AMH do?
Regresses Müllerian duct
What do Leydig cells produce?
Testosterone
What is the role of testosterone in development?
Maintains Wolffian ducts (male internal genitalia)
What is DHT and its function?
A testosterone derivative that masculinises external genitalia
What promotes ovarian development in absence of SRY?
Wnt4, RSPO1, and Foxl2
What are bipotential gonads?
Undifferentiated gonads capable of becoming testis or ovary
Where do PGCs migrate from?
From the epiblast to the genital ridge
What signals guide PGC migration?
KIT, NANOS3, DEAD END1
What are Müllerian ducts?
Precursor of female internal genitalia
What are Wolffian ducts?
Precursor of male internal genitalia
What condition results from androgen insensitivity?
Phenotypic female with XY karyotyoe (AIS)
What is Klinefelter Syndrome?
XXY makes - infertility, hypogonadism
What is Turner syndrome?
XO females - streak ovaries, infertility
What is the role of Pitx2?
Establishes left-sided organ asymmetry during L-R patterning
