Question

In the experiment in which transgenic mice were used to identify the male determining region of the Y chromosome, which of the following statements is true?

1) An egg was fertilized by a sperm carrying only the Y chromosome.
2) Restriction enzymes were used to detect the Sry region of the chromosome.
3) X and Y chromosomes were injected into the egg of a female mouse.
4) X chromosomes were injected into an egg.
5) DNA containing only the mouse Sry region was injected into normal XX mouse eggs and most of the offspring develop into males.

Answer 1

The correct statement in the transgenic mouse experiment is that DNA with the mouse Sry region was introduced into XX mouse eggs, leading to male offspring, highlighting the role of Sry in male sex determination.

Step-by-step explanation:

In the experiment involving transgenic mice to identify the male determining region of the Y chromosome, the true statement is that DNA containing only the mouse Sry region was injected into normal XX mouse eggs and most of the offspring developed into males.

This suggests that the introduction of the Sry gene is sufficient to trigger the development of male characteristics in an otherwise genetically female (XX) mouse. The presence of the Sry gene activates a cascade of events, including the secretion of testosterone by testes, which is critical for the development of the male reproductive system.