GENETICS AND EVOLUTION
GENETIC BASIS OF INHERITANCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The male needs two copies of the gene but will express the trait regardless of whether the alleles are dominant or recessive.
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The male needs two copies of the gene but will express the trait only if both alleles are dominant.
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The male needs only one copy of the gene and will express the trait regardless of whether the allele is dominant or recessive.
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The male needs only one copy of the gene but will express the trait only if the allele is dominant.
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Detailed explanation-1: -X-linked recessive inheritance refers to genetic conditions associated with mutations in genes on the X chromosome. A male carrying such a mutation will be affected, because he carries only one X chromosome. A female carrying a mutation in one gene, with a normal gene on the other X chromosome, is generally unaffected.
Detailed explanation-2: -The correct option is d. males always inherit these traits from their mothers. Biologically males get their X chromosome from their mother and Y from their father. The sex-linked trait on the X chromosome is recessive due to the presence of another X chromosome in females.
Detailed explanation-3: -X-linked disorders are caused by variants in genes on the X chromosome, one of the two sex chromosomes in each cell. In males (who have only one X chromosome), an alteration in the only copy of the gene in each cell is sufficient to cause the condition.
Detailed explanation-4: -In the case of an X-linked disease, it is usually males that are affected because they have a single copy of the X chromosome that carries the disease-causing mutation. In females, the presence of a second, non-mutated copy may cause different, milder, or no symptoms of a sex-linked disorder.