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Abnormalities in the number of X chromosomes tend to be milder than the same abnormalities in autosomes because of ________.

a) X-inactivation
b) Y-linkage
c) Hemizygosity
d) Dosage compensation

User Jcadam
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Final answer:

Abnormalities in the number of X chromosomes tend to result in milder effects than autosomal abnormalities due to a process called X-inactivation, which leads to dosage compensation and generally mild phenotypic effects.

Step-by-step explanation:

Abnormalities in the number of X chromosomes tend to be milder than the same abnormalities in autosomes because of X-inactivation. This molecular process allows females to compensate for their double genetic dose of the X chromosome. During early development, one X chromosome in each cell is inactivated and becomes a Barr body, ensuring that each cell uses the genes from only one X chromosome, preventing an overdose of X-linked gene expression.

An individual with an abnormal number of X chromosomes will inactivate all but one X chromosome in each cell. This inactivation process is associated with mild mental and physical defects and sometimes sterility. The random nature of which X chromosome is inactivated leads to a phenomenon called dosage compensation, allowing for generally mild phenotypic effects compared to similar abnormalities in autosomes.

User Khachik
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