[Campbell Biology P.1079] In Jost's experiment, the surgical removal of the portion of each e... | Practice Question

In Jost's experiment, the surgical removal of the portion of each embryo that would form the ovaries or testes effectively blocked the normal process of gonad development and subsequent hormone production. Considering the results, what does this experiment suggest about the default pathway of mammalian genital development?

  • A: Male genital development is the default pathway, requiring no hormonal signals.
  • B: Female genital development is the default pathway, occurring in the absence of specific gonadal signals.
  • C: Both male and female development require specific hormonal signals from the gonads to proceed.
  • D: The default pathway is determined by chromosomal sex only, independent of hormones.

Explanation

The experiment's results, particularly the fact that XY embryos developed female genitalia when their embryonic gonads were removed, strongly suggest that female development is the default pathway in mammals. It implies that if no specific signal like androgens from male gonads is present, the embryo will develop along the female line, regardless of its chromosomal sex. The XX embryos also developed as female regardless of gonad removal, supporting the idea that female development doesn't require gonadal signals.