The Genetics of Puberty

Question 1

What is the male karyotype?

Answer 1

46 XY

Question 2

What is the female karytope?

Answer 2

46 XX

Question 3

What gene is responsible for male development?

Answer 3

SRY gene

Question 4

Where do the germ cells migrate from and to?

Answer 4

Yolk sac. They move toward the gonadal ridge

At this point they can become male or female (SRY gene determines this)

Question 5

What happens in the presence of the SRY gene?

Answer 5

Sertoli Cells and Leydig cells are formed

Question 6

What do the sertoli cells and leydig cells do?

Answer 6

Sertoli - Anti mullerian Hormone

Leydig - Testosterone

Question 7

What does Anti mullerian hormone do?

Answer 7

This stops the mullerian (paramesonephric ducts forming) and encourages growth of the wolffian (mesomephric ducts)

Question 8

What do the mesonephric (Wolffian ducts) do?

Answer 8

Form the ejaculatory duct, Vas deferens and epididymis

Question 9

What happens in the absence of an SRY gene?

Answer 9

The paramesonephric (Mullerian ducts) develop

Question 10

What does the paramesonephric duct form?

Answer 10

The upper part of the vagina, the uterus and fallopian tubes (all from mesoderm)

Question 11

What pulls the testes down to the scrotum

Answer 11

Gubernaculum