Why can the Lyon hypothesis not be tested in a human female

Why can the Lyon hypothesis not be tested in a human female who is homozygous for one allele of the X-linked G6PD gene

Solution

Answer d:One cannot test Lyon\'s hypothesis with homozygous X Linked gene because test require identification of allelic alternative to see difference in X chromosome activity.

Human Glucose 6 phosphate is controlled by X linked gene heterozygous female for four different allelic form of G6PD hence answer d is correct

Note: Lyon\'s hypothesis states inactivation of X chromosome occur during early embryonic development therefore all progeny cell have same X chromosome inactive.