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If a mother is affected by an X-linked dominant condition and the father is not, which children can inherit the condition?

only males
neither males nor females
both males and females
only females

1 Answer

3 votes

Answer:

both males and females

Step-by-step explanation:

The sex chromosomes in male and female humans are X and Y chromosomes. X-linked traits are those traits which are associated with the X- chromosome.

According to the question, the trait is passed on a X-linked dominant condition, which means that the possession or not of the condition is dependent on the presence of the dominant X-chromosome. The dominant X-chromosome will always express itself even when in an heterozygous state with a normal X-chromosome i.e Xx. Hence, only a individual recessive for the X-chromosome will be normal.

A mother that is affected by the X-dominant condition will either possess a; XX or Xx genotype while a father that is normal (not affected) will possess a (xY) genotype. Since the mother passes one of her X chromosomes to her sons and the other to her daughters, both male and female children will be affected by the condition.

N.B: If the mother is heterozygous for the affected X-chromosome (Xx), half of her sons and half of her daughters will inherit the condition but if the mother contains two dominant X-chromosomes (XX), all of her sons and daughters will inherit the condition.

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