In Mammals, Individuals with Two X Chromosomes Are Female, and Individuals

question 39

Multiple Choice

In mammals, individuals with two X chromosomes are female, and individuals with an X and a Y chromosome are male.It had long been known that a gene located on the Y chromosome was sufficient to induce the gonads to form testes, which is the main male-determining factor in development, and researchers sought the product of this gene, the so-called testes-determining factor (TDF) .For several years, the TDF was incorrectly thought to be a zinc finger protein encoded by a gene called BoY.Which of the following observations would most strongly suggest that BoY might NOT be the TDF?

• A)Some XY individuals that develop into females have mutations in a different gene, SRY, but are normal at BoY.
• B)BoY is not expressed in the adult male testes.
• C)Expression of BoY in adult females does not masculinize them.
• D)A few of the genes that are known to be expressed only in the testes have binding sites for the BoY protein in their upstream regulatory sequences, but most do not.

---

Definitions:

Behavior

Actions or reactions of an object or organism, usually in relation to the environment, which can include activities and mechanisms not observable by others.

Gamma Knife Surgery

A form of radiation therapy that precisely targets brain tumors and other abnormalities with highly focused gamma rays, minimizing damage to surrounding healthy tissue.

Psychosurgery

Surgery intended to promote psychological changes or to relieve disordered behavior.

Obsessive-Compulsive Disorder

A mental health disorder characterized by recurring, unwanted thoughts (obsessions) and repetitive behaviors (compulsions).