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Hemophilia is an X-linked recessive trait. If a girl is a hemophiliac then:Group of answer choicesshe received a hemophilia allele from her motherher father must have hemophiliaall of her sons will have hemophiliaall of the above choices are correct

User Laurance
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Hemophilia is an X-linked recessive trait.

This sickness is presented in males, since they only have one X chromosome, while females are usually carriers and pass on the recessive chromosomes to their children.

It is extremely rare for a female to present hemophilia but not impossible. For a female to have the sickness, she must present the recessive allele in both X chromosomes.

Let "X" represent the normal chromosome and " X' " represent the chromosome with the recessive allele, then a female with hemophilia will have a genotype:


X^(\prime)X^(\prime)

This girl received one recessive allele from her father and one from her mother.

X' from her father → he must be a hemophiliac since males with the recessive allele always present the sickness

X' from her mother → she is a carrier

The X chromosome of males is inherited from the mother, since the mother has two X chromosomes carrying the recessive allele for hemophilia, then all of her children will receive the recessive allele.

This means that all of her daughters will be carriers and all of her sons will have the sickness.

All given options are correct.

User Hnin
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