CELL DIVISION
MEIOSIS AND GENETIC VARIATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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mothers always pass the disorders on to their sons.
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it only takes one copy of the gene to affect males.
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it only takes one copy of the gene to affect females.
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it takes two copies of the gene to affect males.
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Detailed explanation-1: -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-2: -Fathers cannot pass X-linked recessive conditions to their sons. When a son inherits a mutated gene on the X chromosome from his mother, the genetic condition is more likely to occur. X-linked recessive conditions most often occur in males.
Detailed explanation-3: -What is X-linked inheritance? There is a 50 percent chance that daughters carry the gene and can pass it to the next generation. There is a 50 percent chance that a daughter will not carry the gene and, therefore, cannot pass it on. There is a 50 percent chance that sons do not have the gene and will be healthy.
Detailed explanation-4: -Diseases caused by mutations in genes on the X chromosome are called X-linked diseases. Remember, males do not experience XCI because they only have one X chromosome. So, if males have a disease-causing gene on their X chromosome, it will be active and more likely to cause disease.
Detailed explanation-5: -The X must come from the heterozygous mother; therefore, each son has a 50% chance of inheriting the recessive allele.