What experiment helps confirm that the SRY region is responsible for maleness?

The experiment that helps confirm that the SRY region is responsible for maleness involves breeding mice that lack the SRY region. The SRY gene, located on the Y chromosome, plays a critical role in male sex differentiation. When researchers breed mice that do not possess this gene, they can observe the resulting phenotype of the offspring.

In mice without the SRY gene, regardless of their genetic sex (XY or XX), the absence of this gene leads to the development of female characteristics. This clear phenotypic manifestation affirms the SRY gene's role as the master switch for male sex determination. The linkage of this gene to the male phenotype connects the presence of SRY with male anatomical and physiological traits, establishing a concrete foundation for its responsibility in maleness.

Other options such as analyzing X chromosome patterns in females or examining chromosomes of non-mammalian species do not directly test the influence of the SRY gene on sexual differentiation. Similarly, observing sex ratios in fruit flies provides insights into genetic inheritance and sex determination but does not pinpoint the role of the SRY region specifically in mammals. Thus, breeding mice lacking the SRY gene stands as the most definitive approach to confirm the gene's role in male sex determination.