Assertion : Females, homozygous for genes on the X chromosomes do not express a trait more markedly than do hemizygous males
Reason: Dosage compensation mechanism accounts for effective dosage genes in males and females.

Options

A. If both assertion and reason is true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason is false

Answer

A

Explanation

Female have two X chromosomes and males have only one X chromosome. Thus, a dosage compensation mechanism must be present through which the effective dosage of genes of the two sexes is made equal. This is achieved by inactivation of one X chromosome in females which gets condensed and become heteropyknotic. Since only one X chromosome is required for normal metabolision in cells of females, the other X chromosome has the capability in others, Thereforem dosage compensation regulates the enzyme level of males and females.