Question

1. Sex determination in Mammals. You have identified a gene that you have named “mont1” (for ‘make ovaries not testes’) that is expressed at the time when the bipotential gonad becomes specified to become an ovary. Because of this “show it” evidence that mont1 is expressed in the right place at the right time, you hypothesize that mont1 is a critical regulator of the female primary sex determination pathway to specify ovary development.
   1. From what you know about the primary sex determination pathway for ovary development, what signaling pathway would you predict may activate mont1 expression?
   2. What “lose it” experiment could you do to determine if mont1 is necessary for ovary development. Briefly describe the expected result. (As in … I would do X experiment and expect to see Y result if mont1 is necessary for ovary development).
   3. What “move it” experiment could you do to determine if mont1 is sufficient for ovary development. Briefly describe the expected result. (As in … I would do X experiment and expect to see Y result if mont1 is sufficient for ovary development).

Answer 1

a.

• The development of any organ system requires cellular signaling.0
  

Gonadogenesis includes both cellular and morphological events.

b. i would do the knock out experiment where mont1 gene within an xx female will be knocked out and will prove the abscence of ovary development.

c. i would take the DNA region that includes the mont1 gene and inject into the pronuclei of newly fertilized XY mouse zygotes. It will prove that the male mice start to develop ovaries, female accessory organs, and female genitalia.