LIFE SCIENCE

OBJECTIVE LIFE SCIENCE

GENETICS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Why is the gene for a disease or disorder more likely to be found on the X chromosome than Y?
A
The X chromosome has many more genes
B
The Y chromosome has many more genes
C
Either A or B
D
None of the above
Explanation: 

Detailed explanation-1: -Not to stir up a battle of the sexes, but the X chromosome (females have two of them, while males have one) is five times larger than the Y chromosome, and has 10 times the number of genes. That means it carries more traits-and diseases-than the Y chromosome.

Detailed explanation-2: -X-linked recessive diseases most often occur in males. Males have only one X chromosome. A single recessive gene on that X chromosome will cause the disease. The Y chromosome is the other half of the XY gene pair in the male.

Detailed explanation-3: -Males are affected more often than females, because the gene is located on the X chromosome.

Detailed explanation-4: -In females (who have two X chromosomes), a variant would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females.

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